The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results
Fabien Anthonioz, François Ménard, Christophe Pinte, Jean-Baptiste Le Bouquin, Myriam Benisty, Wing-Fai Thi, Olivier Absil, Gaspard Duchêne, Jean-Charles Augereau, Jean-Phillipe Berger, Simon Casassus, Gilles Duvert, Bernard Lazareff, Fabien Malbet, Rafael Millan-Gabet, Matthias R. Schreiber, Wesley Traub, Gérard Zins
AAstronomy & Astrophysics manuscript no. arxiv c (cid:13)
ESO 2014December 9, 2014
The VLTI / PIONIER near-infrared interferometric survey ofsouthern T Tauri stars. I. First results (cid:63) . F. Anthonioz , F. Ménard , , C. Pinte , J-B. Le Bouquin , M. Benisty , W. -F. Thi , O. Absil , G. Duchêne , , J.-C.Augereau , J. -P. Berger , S. Casassus , G. Duvert , B. Lazare ff , F. Malbet , R. Millan-Gabet , M.R. Schreiber , W.Traub , , and G. Zins UJF-Grenoble 1 / CNRS-INSU, Institut de Planetologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041,France UMI-FCA, CNRS / INSU France (UMI 3386) , and Universidad de Chile, Santiago, Chile European Southern Observatory, D-85748, Garching by München, Germany Département d’Astrophysique, Géophysique et Océanographie, Université de Liège, 17 Allée du Six Août, B-4000 Liège, Belgium Astronomy Department, University of California, Berkeley, CA 94720-3411 USA California Institute of Technology, Pasadena, CA 91125, USA. Jet Propulsion Laboratory, California Institute of Technology,Pasadena, CA, 91109, USA. Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile. Departamento de Fisica y Astronomía, Universidad de Valparaíso, Valparaíso, Chileaccepted December 2014
ABSTRACT
Context.
The properties of the inner disks of bright Herbig AeBe stars have been studied with near infrared (NIR) interferometryand high resolution spectroscopy. The continuum (dust) and a few molecular gas species have been studied close to the central star;however, sensitivity problems limit direct information about the inner disks of the fainter T Tauri stars.
Aims.
Our aim is to measure some of the properties (inner radius, brightness profile, shape) of the inner regions of circumstellar disksurrounding southern T Tauri stars.
Methods.
We performed a survey with the VLTI / PIONIER recombiner instrument at H-band of 21 T Tauri stars. The baselines usedranged from 11 m to 129 m, corresponding to a maximum resolution of ∼ ∼ Results.
Thirteen disks are resolved well and the visibility curves are fullysampled as a function of baseline in the range 45-130 mfor these 13 objects. A simple qualitative examination of visibility profiles allows us to identify a rapid drop-o ff in the visibilities atshort baselines( < λ ) in 8 resolved disks. This is indicative of a significant contribution from an extended (R > ff and the amount of dust thermal emission changes fromsource to source suggesting that each disk is di ff erent. A by-product of the survey is the identification of a new milli-arcsec separationbinary: WW Cha. Spectroscopic and interferometric data of AK Sco have also been fitted with a binary + disk model. Conclusions.
The visibility data are reproduced well when thermal emission and scattering from dust are fully considered. Theinner radii measured are consistent with the expected dust sublimation radii. The modelling of AK Sco suggests a likely coplanaritybetween the disk and the binary’s orbital plane.
Key words.
Techniques: interferometry – Stars: variables: T Tauri – Protoplanetary disks – Stars: binaries
1. Introduction
Gas-rich circumstellar disks around young stars (also known asprotoplanetary disks) are central to the formation process of bothstars and planets. They contain the mass reservoir to fuel accre-tion onto the central star, they are the vector by which angularmomentum is evacuated by bipolar outflows, and they are thesites where planetesimals grow and planets form. Based on di-rect imaging of planetary-mass bodies embedded in debris disks( β Pic, Lagrange et al. (2010); Fomalhaut, Kalas et al. (2008);HR 8799, Marois et al. (2010)) and on the coplanarity in the so-lar system and extrasolar systems (Figueira et al. 2012), there isnow little doubt that planets do form in disks. (cid:63)
Data obtained at the ESO VLTI as part of programmes 086. C-0433,087. C-0703, 088. C-0670, and 089. C-0769.
The inner central regions (R <
10 au) of these protoplane-tary disks are di ffi cult to observe directly because of their smallapparent size. Unfortunately, this is where the density is highenough for rocky terrestrial planets and gas-giant embryos toform within reasonable timescales compared to the disk lifetime.A knowledge of the geometry, temperature, and content of theseregions is critical for understanding how mass is transferred ontothe star and how planets may form, agglomerate, and migrate.Near-infrared long-baseline interferometry has, in principle,the necessary angular resolution to resolve these regions, thoselocated in the range 0.5-10 au from the central star at the distanceof the nearest star forming regions (i.e., d =
140 pc). However, toobtain reliable or detailed information on the disk location andshape, a good two-dimensional spatial frequency (hereafter uv)coverage is needed. This is not easily available, in particular forfaint targets.
Article number, page 1 of 19 a r X i v : . [ a s t r o - ph . S R ] D ec ecause they are relatively bright, Herbig AeBe stars havebeen amply observed by near infrared (NIR) interferometers inthe past, and the dust and gas distributions in the inner regionsof their disk are now reasonably well characterised (see, e.g.,Dullemond & Monnier (2010) and references therein for an ex-haustive review of the inner disks around Herbig stars). Interest-ingly, for these stars, a fairly tight correlation is found betweenthe luminosity of the central star and the characteristic radius thatthe disk emission comes from (Monnier & Millan-Gabet 2002).This radius was rapidly associated to the dust sublimation radius.On the other hand, observations are much less common forthe fainter solar-like counterparts of Herbig stars, the T Tauristars, because interferometers are usually not sensitive enoughor have a limited number of baselines available. Also, becauseof the lower luminosity and temperature of the central T Tauristars, the inner rim of their dust disks, typically 0.1 au in radiuscorresponding to ∼ ff ort, i.e.,using full radiative transfer including light scattering and ther-mal emission rather than dust thermal re-emission alone. Theyshow for that case from a generic model, that T Tauri stars can bep put back on the expected correlation between luminosity anddisk sublimation radius. One goal of this paper is to verify thatsuggestion further. Detailed fitting of individual targets was notdone, however, and these predictions could not be verified owingto the limited sampling of the uv plane. This limited coverageresults in significant ambiguities in the models. These ambigui-ties can be mitigated or solved by a broader coverage in baselinelengths and orientation.PIONIER (Le Bouquin et al. 2011) at the ESO-VLTI of-fers the possibility to recombine the light from four telescopesat once. This recombiner is also more sensitive than previousones, allowing good measurements to be obtained for the fainterT Tauri stars. Interferometric observations with four telescopesprovide six independent baseline measurements at once, as wellas three independent closure phases. This is an improvementover previous interferometric recombiners in terms of sensitivityand rapid uv coverage.In this paper we report observations of 21 T Tauri stars and2 Herbig stars from the southern hemisphere with the interfero-metric instrument PIONIER. In section 2, we give more detailsabout the observations. Sections 3, 4, and 5 are devoted to thestatistical results for non-detection and generic modelling of thevisibilities of our sample. Section 6 is devoted to binaries, andwe conclude in section 7.
2. Observations, data reduction, and sample
The sample comprises 21 T Tauri stars (spectral type G or later)and 2 Herbig Ae stars (spectral types F and A) brighter than H = ∼ – a significant NIR excess that traces hot dust located close tothe star, – a resolved image from radio interferometry tracing the colderdust located in the outer disk, or – a scattered light image.All the targets are located in southern star forming fegionsand young associations: six are located in the Lupus associa-tions, four in the TW Hya Association (or co-moving group),three in the ρ Oph cloud, three in Upper Scorpius, two in CrA,and one each in the Upper Centaurus Lupus, Argus, ChamaleonI, and β Pic moving groups . The remaining star is located inOrion. The coordinates, spectral type, distance, and magnitudein H for these stars are summarised in Table 1. Five of these stars(AS 205 A, V2129 Oph, V2508 Oph, S CrA, and TW Hya) havebeen previously observed by NIR interferometry (Eisner et al.2005, 2007, 2010; Menu et al. 2014; Vural et al. 2012) In our sample, 12 objects are previously known binaries or mul-tiple systems. For 6 of them the companion lies at a separationlarge enough to not be included in the field of view of PIONIER,which is approximated by the FWHM of the fibre response func-tion, i.e., 250mas. These can be considered as made of two sep-arate single stars. We observed the two members of the TWA 3system separately.For the six other targets, the companion is included in thefield of view. The companion of V4046 Sgr has a separationof 0.56 mas, which is much less than the resolving power ofPIONIER. It is not resolved by our observations. The sameapplies for V380 Ori C. HT Lup has two companions at 2.8"and 0.126". HT Lup C is possibly detected in our short baselineobservations, while there is no indication of its presence on thelong baseline observations. This object will be discussed morein detail in a dedicated paper. Finally, V380 Ori B and HNLup B are not detected in our observations because they wouldproduce large closure phases up to 60 ◦ and ∼ ◦ , respectively,while the observed closure phases are compatible with 0. Asummary of the flux ratio and separation of the multiple systemsstudied here is given in Table 2. Our survey also reveals thebinarity of WW Cha. For this star and the three last knownbinaries (AK Sco, V1000 Sco, and TWA 3A), the companion isclose enough to disrupt the inner part of the disk, meaning thatthese objects do not follow any (simple or not) size-luminosityrelationship. We thus discuss these four targets separately fromthe rest of the sample, in § 6. We take the result with the higher membership probability from Maloet al. (2013) for FK Ser and V4046 Sgr.Article number, page 2 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
Table 1.
Position, spectral type, distance, H magnitude, and binarity of the sample. For the binarity, "
Unresolved " means that the companionis unresolved by PIONIER,"
Yes " means that the star has a detected companion in PIONIER’s half field of view (125 mas), "
Border " that thecompanion lies on the edge of the field of view, stars with "
Outside " have a companion with a separation much larger than the field of view, and" no " indicates that the star is single. Star R. A. Dec SpT dist.(pc) Log( L / L (cid:12) ) Refs H-mag Resolved? binary?V380 Ori 05 36 25 -06 42 57 A1e 510 1.99 1,2,3 6.96 yes Unresolved,BorderTWA 07 10 42 30 -33 40 16 M3.2 34 -0.94 4 7.13 no noTW Hya 11 01 51 -34 42 17 M0.5 56 -0.72 4 7.55 marginally noWW Cha 11 10 00 -76 34 57 K5 160 0.74 5,6 7.21 yes YesTWA 3A 11 10 28 -37 31 52 M4.1 35 -0.92 4 7.53 yes Yes, OutsideTWA 3B 11 10 28 -37 31 52 M4.0 35 -1.10 4 8.15 no OutsideHT Lup 15 45 12 -34 17 30 K2 150 0.74 4 6.87 yes Border, OutsideHN Lup 15 48 05 -35 15 52 M1.5 150 -0.28 7,14 8.1 yes OutsideGQ Lup 15 49 12 -35 39 05 K7 150 0.17 27 7.70 yes OutsideRU Lup 15 56 42 -37 49 15 K7 150 0.16 8,9,22 7.82 yes noV1149 Sco 15 58 36 -22 57 15 G6 145 0.39 10 7.69 yes noRY Lup 15 59 28 -40 21 51 G0V 150 0.41 2,11,12 7.69 yes noMY Lup 16 00 44 -41 55 31 K0 150 -0.20 13,23 8.69 no noV1000 Sco 16 11 08 -19 04 46 K2 145 0.44 14,24 7.98 yes YesAS 205 A 16 11 31 -18 38 24 K5 125 0.60 15 6.75 yes OutsideV2129 Oph 16 27 40 -24 22 04 K5 121 0.15 26 7.67 yes noV2508 Oph 16 48 45 -14 16 35 K6 125 0.46 16,17 7.57 yes noV1121 Oph 16 49 15 -14 22 08 K5 130 0.176 2,12 7.45 yes noAK Sco 16 54 44 -36 53 18 F5V 145 0.61 × × References. (1) Manoj et al. (2006), (2) van Leeuwen (2007), (3) Alecian et al. (2013), (4)Herczeg & Hillenbrand (2014), (5)Luhman (2007),(6) Whittet et al. (1997),(7)Hughes et al. (1994), (8)Lommen et al. (2007), (9)Stempels et al. (2007), (10) Yang et al. (2012), (11) Reipurth et al.(1996), (12) Artemenko et al. (2012), (13) Romero et al. (2012), (14) Sartori et al. (2003), (15)Bast et al. (2011), (16)Andrews et al. (2010), (17)de Geus et al. (1989), (18) Alencar et al. (2003), (19) Donati et al. (2011),(20) Torres et al. (2006), (21) Forbrich & Preibisch (2007), (22) thispaper, (23) Gregorio-Hetem & Hetem (2002), (24) Wahhaj et al. (2010), (25) McDonald et al. (2012), (26) Donati et al. (2011), (27) Dai et al.(2010)
The observations were performed with the PIONIER 4-telescopebeam recombiner instrument (Le Bouquin et al. 2011) usingthe four 1.8 m Auxiliary Telescopes (AT) of the Very LargeTelescope Interferometer (VLTI, Haguenauer et al. (2010)) atthe Paranal Observatory of the European Southern Observatory(ESO) during five di ff erent semesters from period P86 to P90.The observations were obtained in visitor mode. In total, 17.5nights were allocated to the programme with a long-baselineconfiguration distributed in nine sub-runs over four semesters(P86-P89). Seven more nights were allocated with short a base-line configuration during P90. For the long baseline survey,seven full nights (40%) were lost from adverse weather condi-tions, the weather conditions being average for the remaining10.5 nights. For the short baseline run, nearly all the observabletime (6.5 nights out of 7) was lost due to weather, and only 4 starscould be observed. For Period 86, the stations were A0-K0-G1-I1 and for P87, P88, and P89 the stations were A1-K0-G1-I1,providing separations on the ground between telescopes rangingfrom 47 meters to 129 metres, equivalent to a maximum angularresolution of ∼ ff erent interferometric calibrators as muchas possible. A typical observation sequence (5 blocks) was Cal- ibrator 1 — Science Target — Calibrator 2 — Science Tar-get — Calibrator 1. The calibrators were chosen from theJSDC (Lafrasse et al. 2010) and selected to be unresolved sin-gle stars. The calibrators have H-magnitudes that are usuallya little brighter than the science targets (between 0.0 and 0.75H-mag brighter). Each block, either science or calibrator, wascomposed of 5 or 10 exposures, each of which composed of 100fringe scans, followed by the acquisition of the dark frame andthe internal, flat-fielded flux splitting ratio (Le Bouquin et al.2011). Data were reduced and calibrated with the dedicated pn - drs package (Le Bouquin et al. 2011). Typical errors on our mea-surements are ∼
5% for the visibilities and ∼ ◦ on the closurephases. The final, calibrated interferometric data acquired dur-ing this survey are presented in Appendix B. Our observationscan be roughly separated into three distinct groups, dependingon the main signature of interferometric data: unresolved tar-gets, binaries, and stars with a resolved disk.
3. Unresolved targets
Six targets in the survey are unresolved, meaning that theirsquared visibility at the longest baselines are compatible withunity. To set limits on the maximum brightness of their disks,we follow a similar linear fitting procedure, as described in diFolco et al. (2007). The procedure consists of fitting the visi-bility data with a model made of a central star surrounded bya faint, fully resolved uniform disk. Diameters of the stars are
Article number, page 3 of 19 able 2.
Separation, luminosity ratio and references for the observedbinaries.
Star Sep. (mas) L ( comp ) / L ( prim ) Refs.WW Cha 6.31 ± . ± ± ± ∼ ± ± ± < ± + . − . (10)GQ Lup 732 ∼ ±
10 0.4 ± ±
100 0.095 ± ±
60 0.3 ± ± ± ∼ References. (1) this paper; (2) Andersen et al. (1989); (3) Ghez et al.(1997); (4) Leinert et al. (1994); ; (5) Mugrauer & Neuhäuser (2005);(6) Cohen & Kuhi (1979); (7) Dyck et al. (1982); (8) de la Reza et al.(1989); (9) Byrne (1986); (10) Alecian et al. (2009); (11) Herbig (1973);(12) Mathieu et al. (1989) expected to be 0.22 mas or less, so are unresolved even at thelongest baselines. The visibility, V, as a function of baseline, B,can therefore be written as V ( B ) = (cid:32) V (cid:63) + f disk (cid:33) ≈ − disk , (1)where f disk = F disk / F tot . We then calculate the associated prob-ability of each model p ( f disk ) ∝ e − χ ( f disk ) / (2)and define the confidence interval as the range over which thecumulative probability is greater than 99.6%. The results of thisvisibility fitting are displayed Figure 1. The maximum disk frac-tional luminosity and best χ are listed in Table 3. The maxi-mum disk fractional luminosities are the highest allowed by the3 σ lower limit on the visibilities. However, one has to keep inmind that this assumes fully resolved disks, which may not bethe case, and there is a slim possibility that a very compact un-resolved disk remains in the centre.For unresolved sources, the visibilities are compatible with1.0 but can take slightly higher values because of the uncertain-ties. This is unphysical but numerically allowed by the calibra-tion procedure. Because f disk is always positive, this can explainsome higher χ values, such as for V709 CrA and TWA 3B.These results are consistent with SED analysis of these ob-jects. The SED of these stars shows an excess in the mid-infraredand sub-millimetre range, while the optical and near-infraredSED is compatible with a naked star without excess coming fromeither thermal emission or scattered light, suggesting that the in-ner parts of these disk have been cleared (at least down to unde-tectable levels). Table 3.
Upper limits of disk luminosity in H-band for the unresolvedstars.
Star Max F disk / F tot (%) χ / ( nb .v is . )V4046 Sgr 3.16 1.72TWA 07 0.68 0.68V709 CrA 1.09 3.32TWA 3B 2.38 1.91MY Lup 6.31 0.97FK Ser 3.38 0.57 Table 4.
Mean closure phase, mean absolute value of the closure phase,and mean error on the closure phase for each non-binary star with aresolved disk on our sample, in degrees. For all these object, the meanclosure phase and the mean absolute closure phase are compatible with0.
Star CP | CP | σ CP TW Hya -1.54 1.87 2.83HT Lup -1.10 2.13 2.90GQ Lup -1.70 1.70 2.10RU Lup -2.09 2.21 2.11RY Lup -2.58 3.16 3.58V1149 Sco -0.01 1.52 3.08AS 205A -0.98 1.29 1.59V2129 Oph -0.67 2.34 3.25V2508 Oph -4.05 6.87 6.86V1121 Oph -0.27 2.37 5.10S CrA -2.73 2.73 2.51V380 Ori 1.17 4.20 4.88HN Lup 1.02 1.40 4.94
4. Simple models to characterise the visibilityprofiles of resolved disks
In addition to the unresolved sources (see §3) and to the resolvedbinary systems (see §2.2 and §7), there are 13 (e ff ectively) singletargets in the sample that show a clear signature of the surround-ing disk in their visibility profiles. Below we devise two simplemodels of disks in order to interpret and describe the visibilitydata of our sample. For this preliminary modelling, we consid-ered pole-on models only because the closure phase signals areweak (usually compatible with zero as we can see from the clo-sure phase profiles displayed Figure B.1 and Table 4), and wealso neglected the eventual spread in the data caused by di ff er-ent projected baseline PA. The general properties are of interesthere. In-depth model fitting that involves several other data setswill be presented elsewhere. We first fit the visibility profiles with a ring model (hereafter thethermal model) discussed in Eisner et al. (2003). This modelassumes that all the energy coming from the disk and the pu ff ed-up inner rim is due to thermal emission. The model is made ofa ring of constant brightness distribution and of width-to-radiusratio w = .
18. The squared visibility V of the system (the starand the thermal ring) is V = (cid:32) + f therm V rin g + f therm (cid:33) , (3) Article number, page 4 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
V4046 Sgr0.91.01.1 TWA 07 V709 CraTWA 3B 0 20 40 60 800.91.01.1 MY Lup 0 20 40 60 80 FK Ser2f disk
0 20 40 60 80
Baseline (M λ ) Baseline (M λ ) Baseline (M λ ) V V Fig. 1.
Visibility profile modelling of the unresolved stars of our survey. The visibility data correspond to the black crosses and error bars, whilethe best visibility fit and lower limit are plotted in dashed black and red lines respectively. The di ff erence between unity and the lower limit can beapproximated to two time the maximal fractional luminosity of the disk. where V rin g is the visibility of the ring written as V rin g = πθ in q (2 w + w ) × [(1 + w ) J (2 π (1 + w ) θ in q ) − J (2 πθ in q )] . (4)The visibility of the star is set to one and is unresolved. Here, J is the Bessel function of the first kind, θ in the opening angle ofthe inner rim (radius), q = √ u + v is the uv-distance, and f therm is the ratio of the thermal ring flux over the stellar flux: f therm . = F disk / F star = F tot . / F star − . (5)This model depends on two parameters, θ in and f therm . Here, f therm can be estimated if one knows the total and the stellarfluxes at H-band. The second model is a refinement of the one presented above. Itis motivated by the PIONIER data obtained in compact configu-ration and the previous predictions made by Pinte et al. (2008).Unfortunately, only three single targets could be observed atshort baselines (HT Lup, RU Lup, and RY Lup), but they allshow a rapid decrease in the visibility profiles at short baselines( < λ ), indicating that an extended component is resolved, atleast partially, and thus larger than R ∼ ff ed-up inner rim. For a10 L (cid:12) star (brighter than all the stars in our survey except forV380 Ori), the emission region (where 99% of the disk emis-sion comes from) is only ∼ ff ed-up rim makes this size smaller because it concentrates an important partof the thermal emission closer to the centre, thus reducing thesize of the emission region This upper limit is half the size ofthe extended component. Lower luminosity values would leadto a correspondingly smaller zone. It seems reasonable to as-sume that the extended component is not due to thermal emis-sion alone. Scattered light appears as a natural candidate. Thisassumption is also motivated by the high albedo of typical diskgrains that can be up to 0.9 for small silicate particles.To check the ability of scattered light to match the data, webuild a composite model where thermal emission (see § 4.1) iscombined with a scattered light component. For simplicity weonly consider isotropic scattering. To determine the radial de-pendence of the scattered flux, we determine the surface bright-ness of a power-law disk characterised by a flaring of its surfacewith exponent β = . τ = H o , and an outerradius set equal to half of PIONIER’s field of view .The surface of a ring of width dr at a radius r of this disk canbe written as dS ( r ) = π r × √ dr + dH = π r × (cid:112) + ( α r β − ) dr (6)where H = H ( r / r ) β is the height of the disk at the radius r , r the reference radius, and α = H β/ r β . This ring is illuminatedby the star with an angle ρ = θ − φ = tan − ( dH / dr ) − tan − ( H / r ) (7) = tan − ( α r β − ) − tan − ( α r β − /β ) (8) This flaring exponent is not the true flaring exponent of the disk,since the optical depth will decrease with the radius (owing to the radialdecrease of the surface density), but calculations with di ff erent flaringvalues (from 1 to 1.25) lead to little di ff erences in the results. In asimilar way, H is not the true scale height of the disk but the verticaldistance up to τ =
1. However, the value of H has no influence on thecalculations. Article number, page 5 of 19 here θ is the slope of the ring, and φ the angle between thering, the star, and the midplane of the disk. Finally, the fluxilluminating the ring is proportional to 1 / ( r + H ) , and the ringhas an albedo A . Combining these terms with equations 6 and 8,the flux scattered by the disk at the radius r is dF ( r ) = π r (cid:112) + ( α r β − ) × A ( r + H ) × sin ( ρ ) dr . (9)This ring flux is finally normalised to 1 and multiplied by theratio f scat = F scat / F (cid:63) between the scattered light flux and thestellar flux, d f scat ( r ) = dF ( r ) ∗ f scat (cid:82) dF ( r ) . (10)This normalisation has the advantage of being independentof the albedo and H (as long as α << V = + f therm V rin g + (cid:82) θ out θ in (cid:16) d f scat V rin g (cid:17) + f therm + f scat . (11)Each emission component shares the same inner radius, so thismodel has three free parameters ( θ in , f therm , and f scat ).Similar to the thermal model, the number of parameters canbe reduced if one knows the disk-to-stellar flux ratio in H band f exc . , which can derived using equation 5 and replacing f therm by f exc . . In this case, and considering now that the excess flux iscoming from both thermal emission and scattering, then f therm can be written f exc . − f scat so the final free parameters of thismodel are θ in and f scat . In the section below we use these twomodels to fit the PIONIER data.
5. Simple fits of the PIONIER data.
For each target, we list in Table 6 the results from both models.The corresponding visibility profile plots are presented Figure2. Two stars have a published excess, f exc . , at H-band: TW Hya(Menu et al. 2014) and S CrA (Vural et al. 2012). To estimatethis excess for the rest of the targets, we performed a spectral de-composition by fitting the visible part of the SED with a Kuruczmodel, with the e ff ective temperature and luminosity fixed to thevalues found in the literature (see Table 1). Then f exc . is derivedusing eq. 5. The resulting excesses are presented Table 5.The range of validity for R in and f therm was derived by com-puting the χ map of the model results, then deriving the associ-ated marginalised probabilities p composite ( f therm ) ∝ ∞ (cid:88) R in = e ( − χ ( R in , f therm ) / (12)and p composite ( R in ) ∝ f tot (cid:88) f therm = e − ( χ ( R in , f therm ) / (13)and defining a 68% confidence interval around the best modelalong each axis (i.e, for R in and f therm ). Equations 12 and 13 arevalid because f therm and R in are sampled uniformly in the models.The validity range of the thermal model was derived similarly, Table 5.
Derived values of f exc for the 13 resolved disks of our survey. f exc is defined as f disk / f star and has been either taken from the literature(TW Hya and S CrA) or estimated by spectral deconvolution. Star f exc TW Hya 1.03 ± . ± . ± . ± . ± . ± . ± . ± .
05S CrA 2.50 ± . ± . ± . ± . χ of each model as a function of R in , then theassociated probability p therm ( R in ) ∝ e − χ ( R in ) / , (14)and finally defining a 68% confidence interval around the bestmodel.We caution that the thermal model provides poorer fits toseveral of the data sets (see Fig. 2). The average value for thethermal models’ reduced χ is 9.2 and is 3.1 for the compositemodel. The median value of the thermal model’s χ red is 4.9 (withvalues up to 25 as presented Table 6, here we neglect V380 Oriand HN Lup that may be associated with envelopes, see below).In this case, meaning with poor models, and although error barsand the validity range can be formally calculated, the exerciceleads to validity ranges for R in that are not representative. Welist them for completeness in Table 6 but caution that these errorsare not reliable for the thermal model.For 5 of the 13 resolved stars, both models lead to similarinner radii estimations. Several explanations are possible: – These disks may be flat or made of grains with low albedo,resulting in less scattering. V2508 Oph and AS 205A mightfall into this category, because the thermal model can fit thevisibility data of their well-resolved, luminous disks. – The uv coverage may be too poor (as for V1149 Sco) or mayshow a large dispersion in the visibility measurements (as forV1121 Oph), resulting in poorly constrained models, – The disk surface brightness may be low (as for TW Hya). Asa consequence, the visibility drop-o ff is small enough that,even with short baselines measurements, both models leadto similar results.For the remaining eight stars – V380 Ori, HT Lup, HN Lup,GQ Lup, RU Lup, RY Lup, V2129 Oph, and S CrA – apply-ing the thermal model results in poorer fits of the visibility pro-files, while the composite model provides a better match (seeFigure 2). Interestingly, we note that the composite model (withscattering) does much better for RU Lup, HT Lup, and RY Lup,the only three disk targets for which short baseline measure-ments are available. Because scattered light is expected to pro-duce clear signatures at short baselines, it will be important toverify the solidity of this trend with more data obtained in com-pact VLTI configurations.We also note that the values of f scat listed in Table 6 varyfrom 0.0 (dominated by pure thermal emission) to above f therm Article number, page 6 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
Table 6.
Inner rim size, thermal excess, scattered excess, and χ red for the composite model (left part), and the thermal model (right part). f scat isthe di ff erence between the total excess flux (estimated from SED analysis) and f therm . . Star Composite model Thermal model R in [au] f therm f scat χ red R in [au] f therm χ red TW Hya 0.111 + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . − . + . −− . + . − . scat , but envelopes may contaminate the re-sults. Excluding them for safety, the values range from 0 to ∼
40% of the total disk flux. This is a wide range that indicatesthat disks are likely to be di ff erent from one another, either inshape or content. The current data does not allow detailed imagereconstruction. However, more interferometric data and detailedmodelling of individual sources, to be performed elsewhere andadding information from several other data sets, will be usefulfor exploring the shape and content of the inner disks around TTauri stars further.A few disk targets are worth a special note, in particular be-cause an extended envelope may a ff ect the interferometric mea-surements, as mentioned above. V380 Ori is associated with amassive (7.6 + . − . M (cid:12) ) envelope (Liu et al. 2011). The envelopeis resolved with the shortest baselines in our observations. It isresponsible for the large visibility decrease at short baselines. Inthis case, both disk models are inappropriate, since incompletebecause of the envelope. The data for HN Lup are scarcer, butSED-fitting permits estimating the excess flux in the H band toroughly about 1.5 times the photospheric flux. This is a huge ex-cess flux that hints at the presence of a possible envelope aroundHN Lup as well. There is a hint, from extended CO line emis-sion, that an envelope may also be associated with V1149 Sco(Dent et al. 2005).A comparison of our values of R in with previous estimatesfrom the literature is also interesting. We find that the inferredinner radius for S CrA with the thermal model is compatiblewith the previous estimates from Vural et al. (2012). The radiiof AS 205 A are also consistent with values found by Eisneret al. (2005) with a pu ff ed-up rim, flared-disk model. However,our inferred radii of TW Hya are slightly smaller than the onefound in Menu et al. (2014) (0.11 au versus 0.3 au). All othersare new estimations.We note that our thermal model leads to similar inner rimradii regardless of whether we fit the whole visibility profile oronly the data between 80 and 90 meters (i.e., the Keck Interfer-ometer and the baseline range used in previous studies by Ake-son et al. (2005) and Eisner et al. (2007)). This is serendipitous,because having ∼
80 m baselines is close to the average base-line range in our coverage. Nevertheless, a comparison remainsuseful with previous studies made with thermal models and with data for this specific restricted range of baselines (see Pinte et al.(2008) and references therein).
We present in Fig. 3 a comparison of the inner radii derived fromthe two models with the sublimation radius estimated for an op-tically thin disk. See the straight and dashed lines in the figure 3,which are calculated with the following prescription: R sublim = (cid:115) (1 + H in / R in ) L star + L acc πσ T sub , (15)where we adopted H in / R in (0.1) and T sub (1500 and 2000 K) fordirect comparison with Eisner et al. (2007). In addition, we plotthe radii calculated by Pinte et al. (2008) using only a thernalring and archival data from Keck and PTI.The radii from the thermal model are compatible with thedust sublimation radius, except for TW Hya. Not surprisinglyperhaps (see Pinte et al. (2008)), the radii calculated with thecomposite model are smaller than their thermal model equiva-lent. They are also consistent with an inner rim at the sublima-tion radius, assuming a 1500-2000K dust sublimation tempera-ture.Two stars have an inferred radius that is small and belowthe 2000K dust sublimation curve: RY Lup and HT Lup. Theirsmall inner rims can be accounted for by large projection e ff ectsof high inclinations. These e ff ects have to be taken into accountproperly to extract better parameters.As presented in this section, geometrical models are su ffi -cient to highlight the general properties of T Tauri disks and, inparticular, here the presence (or absence) of a significant con-tribution from (extended) scattered light. These simple mod-els also highlight the possibility that the inner regions of eachdisk is di ff erent from target to target and that envelopes may alsocontaminate the interferometric signal if not taken into accountproperly. Full radiative transfer modelling is required to derivemore precise parameters about the structure and composition ofthe inner disks. Such modelling is currently underway for all thestars with disks discussed above. These models will be presentedelsewhere. Article number, page 7 of 19 ig. 2.
Plots of the results form the visibility modelling with the thermal and composite models. For each star the black circles and vertical barsare the data points and error bars, and the dotted line represents V =
1. The red lines are the fits with the composite model, and the blue lines arethe fits with the thermal model. Fitting only the visibility point between ∼
47 and ∼
54 M λ (roughly the baseline of the Keck Interferometer, seethe red points and error bars) with the thermal model leads to similar results (green dashed line) for the majority of the stars as fitting the wholevisibility profile.
6. Binaries detected in the survey
The companions to four stars were detected during this survey,three of which were already known from spectroscopy. This isthe first time the binary is resolved spatially for all four objects.Table 7 contains results for WW Cha, V1000 Sco, and TWA 3A:the date of observation, the separation and position angle of eachcompanion, and the flux ratio between companion and primary.AK Sco is discussed in detail below, and its orbital parametersare presented in Table 8.
AK Sco is a double-line spectroscopic binary. We observed itduring seven nights between August 2011 and July 2013 (Ta-ble B.1) with the VLTI configured with long (6 nights) and short(one night in July 2013) baselines. Data were spectrally dis-persed over one or three spectral channels across the H band.The dataset reveals the presence of the central binary plus anextended surrounding environment.A first fit of interferometric data and radial velocities (fromAlencar et al. (2003)) with a model consisting of a binary with-out circumstellar material leads to poor results, with the reduced χ of the fit being χ r =
18 and the residuals showing the signa-
Article number, page 8 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
Table 7.
Date of observation, separation, position angle, astrometric errors, and flux ratio of the observed binaries. The astrometric errors are thesemi major axis a , the semi minor axis b, and the orientation of the error ellipse, θ , around the best fit position of the companion. The flux ratio ofTWA 3A is poorly constrained by the observations. Star Date of observation Sep.(mas) P.A. ( ◦ ) a(mas) b(mas) θ ( ◦ ) F ( comp ) / F (cid:63) WW Cha 2012-07-02 4.73 -140 0.57 0.35 22 0.622012-03-06 6.18 -48.8 0.98 0.40 117 0.622011-02-10 6.44 173.4 0.50 0.18 150 0.62V1000 Sco 2012-07-17 4.33 105.7 0.40 0.19 164 0.342012-08-19 - - - - - - - - - - multiple local minima - - - - - - - - - -TWA 3A 2011-02-09 3.51 108.1 0.57 0.43 1 0.76
Lum (L sol ) R i n ( au ) Fig. 3.
Calculated inner rim for all the single, resolved stars of oursurvey (except V380 Ori and HN Lup) with the composite model (bluetriangles and error bars) and the thermal model (red crosses and errorbars). Radii calculated with thermal models from the literature (Pinte etal. 2008) are also presented by green circles. The blue lines representthe sublimation radius as a function of the stellar luminosity for grainssublimating at 1500 K (straight line) and 2000 K (dashed line). Allestimations assume a pole-on configuration. ture of an extended environment. A second model consisting ofa binary surrounded by a narrow ring (to mimic the inner edgeof the disk) is able to fit radial velocities, visibilities, and closurephase more successfully ( χ r ≈ P , T , e , ω , K a , K b , and γ very well. The addition of the interferomet-ric observations constrained the position angle of the ascendingnode and inclination, Ω and i , respectively, as well as the size ofthe apparent orbit.The inclination of the binary, hence the stellar masses, arecompatible with those found in Alencar et al. (2003). The diam-eter of both stars is less than 0.15 mas and cannot be resolved with the longest baseline of the VLTI, so we consider the star tobe unresolved in the fitting process. The distance is constrainedwith the period, masses, and apparent size of the orbit of thebinary. It is consistent at 1.5 σ level with the value from vanLeeuwen (2007) (d = + − pc), while being more precise.Interferometric observations also constrain the parameters ofthe circumbinary disk (major axis w disk , inclination i disk , posi-tion angle Ω disk , and the fractional flux of the disk f disk ). In-terestingly, at one observation epoch, the binary was at closestapparent separation and was nearly unresolved. At that time, theinterferometric signal was coming mostly from the disk.The number of interferometric data points and the spatial res-olution are not enough to disentangle the exact nature of the en-vironment. A model of a binary plus an extended environment isable to reproduce the signature of the environment. This environ-ment can be either an inclined ring, a uniform disk, or a Gaussiandisk. Depending on the model considered, its diameter variesbetween 3 . disk = .
2) iscompatible with the excess flux in H band.Our data set cannot distinguish between i disk =
60 deg and i disk = −
60 deg, no information on the disk rotation sense isavailable. However, the position angle of the disk is compatiblewith the binary one, and one of the two values of i disk matches theinclination of the orbital plane. Based on that, it seems reason-able to conclude that the two are coplanar, although we acknowl-edge that only a spectro-astrometric measurements of a sense ofrotation of the disk would confirm this definitively. V1000 Sco is a spectroscopic binary, some of its parameters ( P , e , ω , K a , and γ ) have been previously measured by Mathieuet al. (1989). V1000 Sco has been observed twice during ourcampaigns. The first observation set is of good quality, and theobject was observed twice during that night. The companionposition and flux can be modelled without ambiguity. The re-sulting separation and flux ratio are listed Table 2. This binarywas observed again 33 days later. The data is of lower quality,and the modelling of the companion parameters led to numerouslocal minima. Further observations are being collected to fullyconstrain the orbital parameters.Because of the possible presence of excess, uncertain systemage, and systematic uncertainties with evolutionary models, it is Article number, page 9 of 19 ig. 4.
Best fit of AK Sco’s radial velocities and interferometric datawith the binary + ring model. From top left to bottom right: upper left : Apparent trace of the best-fit orbit of the binary (primaryat 0, 0) with the time of observation; upper right : radial velocity fromAlencar with the best-fit orbit; middle left : comparison between model and PIONIER observation forV2; middle right : comparison between model and PIONIER observa-tions for closure phases; lower left : full model of disk + binary as projected on the sky; lowerright : full model of disk + binary as seen pole-on. not possible to reliably convert the H-band flux of the companioninto a mass. More multi-wavelength and / or spectroscopic infor-mation on the companion is needed to assess the binary massratio. This also applies to TWA 3A and WW Cha below. TWA 3A was observed once on February 2011, and the interfer-ometric data are in good agreement with a binary model, witha binary separation of 3.51 mas and flux ratio of 0.76. As forV1000 Sco and WW Cha, further observations will be needed toconstrain this system.
WW Cha has been observed three times between February 2011and July 2012. Each observation shows evidence for binarity
Table 8.
Best fit orbital elements and related physical parameters of AKSco
Parameter Value Uncertainty Unit / definition γ − .
97 0 . − K a . . − K b . . − t p .
410 0 . JD-2400000 P .
609 0 .
001 days e .
47 0 . i
115 3 deg Ω
48 3 deg ω
186 2 deg a app .
11 0 .
04 mas f .
81 0 .
06 H-band flux ratiof disk .
18 0 .
03 flux.env i disk
121 8 deg w disk . . Ω disk
47 10 deg d
141 7 pc M a .
41 0 .
08 M (cid:12) M b .
39 0 .
08 M (cid:12) (high visibility and closure phases variations, see Appendix B).We performed interferometric fitting on these data with a modelconsisting of a binary and a fully resolved component (a disk orenvelope). The amount of data is not su ffi cient to constrain theorbital parameters. While the data of March 2012 is of lowerquality than the two others (giving multiple local minima for theposition of the companion), the fitting of all three data sets givessimilar results for the companion’s flux (0.6 time the flux of theprimary) and the extended component (accounting for 12% ofthe total emission). Figure 5 shows the apparent movement ofthe companion. This motion is not compatible with that of abackground star, and it suggests that the two objects are bound.
7. Summary and conclusion
We observed 23 young stars with PIONIER at the VLTI, 21 TTauri stars, and 2 Herbig Ae stars. Thirteen of these stars havea visibility profile showing the clear signature of a circumstellardisk. We fitted the data with two simple models: a thermal ringmodel and a more complex composite model consisting of thethermal ring model and an additional large scale component. Thecomposite model significantly improves the quality of the fits ineight cases, especially the shape of the visibility curves at shortbaselines. These results strongly support the previous suggestionby Pinte et al. (2008) that the extended component is producedby scattered light. For the five other cases, the fits from the twomodels are of similar quality .All in all, the model results indicate that the amount of scat-tered flux di ff ers from disk to disk, as does the amount of ther-mal emission from the inner rim. This indicates that each diskis probably di ff erent from all others in its fine details. Clearlymore advanced modelling is needed, including more constraintsfrom other data sets, to derive the exact shape and content ofeach inner disks. This will be presented elsewhere.The size of the inner disks (or the inner rims) were also es-timated for disk sources. All the inner disk radii derived fromthe composite model are smaller than their counterparts fromthe thermal model. These radii are consistent with the radii ex- Article number, page 10 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
Fig. 5. χ map for the binary model fitting of WW Cha for the ob-servations of February 2011 (blue), March 2012 (red), and July 2012(green) (for each colour, darker tones mean better χ ). The primaryis represented by the central black star, while the best fit position ofWW Cha companion (i.e., the minimum χ ) is denoted by a cross. Ob-servations of March 2012 produced data of lower quality, leading tonumerous local minima in this map. pected for a dust sublimation temperature of ∼ ffi cult. We stress that, ide-ally, future observations should include better uv coverage andsimultaneous photometry.Another result of this survey is the discovery of a new bi-nary: WW Cha. Its interferometric data can be modelled witha binary system and resolved emission. The companion is seenat a di ff erent position during each observation, but further obser-vations will be needed to fully constrain the orbital parametersof this milli-arcsecond binary. We also re-observed and spatiallyresolved the known binaries V1000 Sco, TWA 3A, and AK Sco.For V1000 Sco and TWA 3A, the separations, position angles,and flux ratios of the systems were derived. For AK Sco, boththe binary system and the inner edge of the circumbinary disk areresolved. The orbital parameters and the distance to the systemwere derived. This model reproduces both the radial velocitymeasurements and the interferometric data. However, the exactshape of the circumbinary environment cannot be constrainedyet from our observations. More data points and longer base-lines are needed. Acknowledgements.
PIONIER is funded by the Université Joseph Fourier (UJF,Grenoble) through its Poles TUNES and SMING, the Institut de Planétologie et d’Astrophysique de Grenoble, the “Agence Nationale pour la Recherche”with the programme ANR EXOZODI, and the Institut National des Science del’Univers (INSU) via the “Programme National de Physique Stellaire” and “Pro-gramme National de Planétologie”. The authors want to warmly thank all thepeople involved in the VLTI project. This work is based on observations madewith the ESO telescopes. It made use of the Smithsonian / NASA AstrophysicsData System (ADS) and of the Centre de Données astronomiques de Strasbourg(CDS). All calculations and graphics were performed with the open source soft-ware
Yorick . We acknowledge funding from the European Commission’s 7 th framework programme (EC FP7) under grant agreement No. 284405 (DIANA)and contract PERG06-GA-2009-256513 and also from Agence Nationale pourla Recherche (ANR) of France under contract ANR-2010-JCJC-0504-01. FM,SC and MS acknowledge support from Millennium Science Initiative, ChileanMinistry of Economy: Nucleus P10-022-F. This research has made use of theSimbad database operated at the CDS, Strasbourg, France, and the Jean-MarieMariotti Center ASPRO and
LITpro services co-developed by CRAL, IPAG,and FIZEAU. We thank the anonymous referee for her / his suggestions forimprovement. References
Akeson, R. L., Boden, A. F., Monnier, J. D., et al. 2005, ApJ, 635, 1173Alecian, E., Wade, G. A., Catala, C., et al. 2009, MNRAS, 400, 354Alecian, E., Wade, G. A., Catala, C., et al. 2013, MNRAS, 429, 1001Alencar, S. H. P., Melo, C. H. F., Dullemond, C. P., et al. 2003, A&A, 409, 1037Andersen, J., Lindgren, H., Hazen, M. L., & Mayor, M. 1989, The Messenger,55, 45Andrews, S. M., Wilner, D. J., Hughes, A. M., Qi, C., & Dullemond, C. P. 2010,ApJ, 723, 1241Artemenko, S. A., Grankin, K. N., & Petrov, P. P. 2012, Astronomy Letters, 38,783Bast, J. E., Brown, J. M., Herczeg, G. J., van Dishoeck, E. F., & Pontoppidan,K. M. 2011, A&A, 527, A119Byrne, P. B. 1986, Irish Astronomical Journal, 17, 294Cohen, M. & Kuhi, L. V. 1979, ApJS, 41, 743Dai, Y., Wilner, D. J., Andrews, S. M., & Ohashi, N. 2010, AJ, 139, 626de Geus, E. J., de Zeeuw, P. T., & Lub, J. 1989, A&A, 216, 44de la Reza, R., Torres, C. A. O., Quast, G., Castilho, B. V., & Vieira, G. L. 1989,ApJ, 343, L61Dent, W. R. F., Greaves, J. S., & Coulson, I. M. 2005, MNRAS, 359, 663di Folco, E., Absil, O., Augereau, J.-C., et al. 2007, A&A, 475, 243Donati, J.-F., Gregory, S. G., Montmerle, T., et al. 2011, MNRAS, 417, 1747Dullemond, C. P. & Monnier, J. D. 2010, ARA&A, 48, 205Dyck, H. M., Simon, T., & Zuckerman, B. 1982, ApJ, 255, L103Eisner, J. A., Hillenbrand, L. A., & Stone, J. M. 2014, mnras, 443, 1916Eisner, J. A., Hillenbrand, L. A., White, R. J., Akeson, R. L., & Sargent, A. I.2005, ApJ, 623, 952Eisner, J. A., Hillenbrand, L. A., White, R. J., et al. 2007, ApJ, 669, 1072Eisner, J. A., Lane, B. F., Akeson, R. L., Hillenbrand, L. A., & Sargent, A. I.2003, ApJ, 588, 360Eisner, J. A., Lane, B. F., Hillenbrand, L. A., Akeson, R. L., & Sargent, A. I.2004, ApJ, 613, 1049Eisner, J. A., Monnier, J. D., Woillez, J., et al. 2010, apj, 718, 774Figueira, P., Marmier, M., Boué, G., et al. 2012, A&A, 541, A139Forbrich, J. & Preibisch, T. 2007, A&A, 475, 959Ghez, A. M., White, R. J., & Simon, M. 1997, ApJ, 490, 353Gregorio-Hetem, J. & Hetem, A. 2002, MNRAS, 336, 197Haguenauer, P., Alonso, J., Bourget, P., et al. 2010, in Society of Photo-OpticalInstrumentation Engineers (SPIE) Conference Series, Vol. 7734, Society ofPhoto-Optical Instrumentation Engineers (SPIE) Conference SeriesHerbig, G. H. 1973, ApJ, 182, 129Herczeg, G. J. & Hillenbrand, L. A. 2014, ApJ, 786, 97Hughes, J., Hartigan, P., Krautter, J., & Kelemen, J. 1994, AJ, 108, 1071Kalas, P., Graham, J. R., Chiang, E., et al. 2008, Science, 322, 1345Lafrasse, S., Mella, G., Bonneau, D., et al. 2010, in Society of Photo-OpticalInstrumentation Engineers (SPIE) Conference Series, Vol. 7734, Society ofPhoto-Optical Instrumentation Engineers (SPIE) Conference SeriesLagrange, A.-M., Bonnefoy, M., Chauvin, G., et al. 2010, Science, 329, 57Le Bouquin, J.-B., Berger, J.-P., Lazare ff , B., et al. 2011, A&A, 535, A67Leinert, C., Richichi, A., Weitzel, N., & Haas, M. 1994, in Astronomical Societyof the Pacific Conference Series, Vol. 62, The Nature and Evolutionary Statusof Herbig Ae / Be Stars, ed. P. S. The, M. R. Perez, & E. P. J. van den Heuvel,155Liu, T., Zhang, H., Wu, Y., Qin, S.-L., & Miller, M. 2011, ApJ, 734, 22Lommen, D., Wright, C. M., Maddison, S. T., et al. 2007, A&A, 462, 211Luhman, K. L. 2007, ApJS, 173, 104
Article number, page 11 of 19 alo, L., Doyon, R., Lafrenière, D., et al. 2013, ApJ, 762, 88Manoj, P., Bhatt, H. C., Maheswar, G., & Muneer, S. 2006, ApJ, 653, 657Marois, C., Zuckerman, B., Konopacky, Q. M., Macintosh, B., & Barman, T.2010, Nature, 468, 1080Mathieu, R. D., Walter, F. M., & Myers, P. C. 1989, AJ, 98, 987McDonald, I., Zijlstra, A. A., & Boyer, M. L. 2012, MNRAS, 427, 343Menu, J., van Boekel, R., Henning, T., et al. 2014, A&A, 564, A93Monnier, J. D. & Millan-Gabet, R. 2002, ApJ, 579, 694Mugrauer, M. & Neuhäuser, R. 2005, Astronomische Nachrichten, 326, 701Pinte, C., Ménard, F., Berger, J. P., Benisty, M., & Malbet, F. 2008, ApJ, 673,L63Reipurth, B., Pedrosa, A., & Lago, M. T. V. T. 1996, A&AS, 120, 229Romero, G. A., Schreiber, M. R., Cieza, L. A., et al. 2012, ApJ, 749, 79Sartori, M. J., Lepine, J. R. D., & Dias, W. S. 2003, VizieR Online Data Catalog,340, 40913Stempels, H. C., Gahm, G. F., & Petrov, P. P. 2007, A&A, 461, 253Torres, C. A. O., Quast, G. R., da Silva, L., et al. 2006, A&A, 460, 695van Leeuwen, F. 2007, A&A, 474, 653Vural, J., Kreplin, A., Kraus, S., et al. 2012, A&A, 543, A162Wahhaj, Z., Cieza, L., Koerner, D. W., et al. 2010, ApJ, 724, 835Whittet, D. C. B., Prusti, T., Franco, G. A. P., et al. 1997, A&A, 327, 1194Yang, H., Herczeg, G. J., Linsky, J. L., et al. 2012, ApJ, 744, 121
Appendix A: Observations log.
Article number, page 12 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results.
Table A.1.
Log of the observations. The di ff erent columns display the name, date of observation, telescopes, configuration number of spectralchannels, and calibrators for each target Star Obs. date Config. Nspec Calibrators Star Obs. date Configuration Nspec CalibratorsGQ Lup 2011-08-06 A1 G1 I1 K0 1 HIP 83779 HN Lup 2012-07-18 A1 G1 I1 K0 1 HIP 78754HIP 77295 HIP 76997HIP 78118 HT Lup 2011-05-21 A1 G1 I1 K0 1 HIP 793552012-07-16 A1 G1 I1 K0 1 HIP 79355 HIP 77672HIP 78754 2011-05-22 A1 G1 I1 K0 1 HIP 776722012-07-17 A1 G1 I1 K0 1 HIP 78754 HIP 79355HIP 78014 2012-07-16 A1 G1 I1 K0 1 HIP 79355MY Lup 2012-04-16 D0 G1 H0 I1 1 HIP 77962 HIP 77672HIP 78716 2013-05-12 A1 B2 C1 D0 1 HIP 77731RU Lup 2011-08-07 A1 G1 I1 K0 1 HIP 77295 HIP 78359HD 135549 RY Lup 2011-08-07 A1 G1 I1 K0 1 HIP 77964HIP 77964 HIP 772952012-07-17 A1 G1 I1 K0 1 HIP 78754 2013-05-12 A1 B2 C1 D0 1 HIP 78456HIP 78014 HIP 782382012-07-18 A1 G1 I1 K0 1 HIP 78754 V1000 Sco 2012-07-17 A1 G1 I1 K0 1 HIP 78551HIP 78014 HIP 796902013-05-12 A1 B2 C1 D0 1 HIP 77388 2012-08-19 A1 G1 I1 K0 1 HIP 82722HIP 77108 HIP 80171V1149 Sco 2011-05-23 A1 G1 I1 K0 1 HIP 78551 WW Cha 2011-02-09 A0 G1 I1 K0 1 HIP 552372012-07-18 A1 G1 I1 K0 1 HIP 78551 2012-03-05 A1 G1 I1 K0 1 HIP 54452HIP 79690 HIP 56876AS 205A 2011-05-22 A1 G1 I1 K0 1 HIP 79377 2012-07-01 A1 G1 I1 K0 1 HD 99015HIP 77338 V4046 Sgr 2011-08-06 A1 G1 I1 K0 1 HIP 899222012-06-10 A1 G1 I1 K0 3 HIP 82515 HIP 899222012-07-19 A1 G1 I1 K0 1 HIP 77338 V2508 Oph 2012-07-17 A1 G1 I1 K0 1 HIP 82525HIP 79377 2012-07-19 A1 G1 I1 K0 1 HIP 82722FK Ser 2011-05-22 A1 G1 I1 K0 1 HIP 91530 HIP 82384TWA 3A 2011-02-09 A0 G1 I1 K0 1 HIP 53487 2012-08-19 A1 G1 I1 K0 1 HIP 82384HIP 54547 HIP 82722TWA 3B 2011-02-09 A0 G1 I1 K0 1 HIP 53487 V2129 Oph 2012-04-16 D0 G1 H0 I1 1 HIP 80784HIP 54547 HIP 77962TWA 07 2011-05-22 A1 G1 I1 K0 1 HIP 51920 2012-07-19 A1 G1 I1 K0 1 HIP 79346HIP 53631 HIP 803552012-07-18 A1 G1 I1 K0 1 HIP 51920 V1121 Oph 2011-08-07 A1 G1 I1 K0 1 HIP 79884HIP 53631 HIP 84459TW Hya 2011-02-09 A0 G1 I1 K0 1 HIP 53487 AK Sco 2011-08-06 A1 G1 I1 K0 1 HIP 82046HIP 54547 HIP 837792011-05-25 A1 G1 I1 K0 1 HIP 51920 HIP 82046HIP 53631 HIP 82046S Cra 2011-08-06 A1 G1 I1 K0 1 HIP 93470 2012-06-10 A1 G1 I1 K0 3 HIP 82515HIP 92639 2012-07-02 A1 G1 I1 K0 1 HD 1524332012-07-17 A1 G1 I1 K0 1 HIP 93611 HD 1543122012-08-19 A1 G1 I1 K0 1 HIP 92858 HD 148841HIP 93611 2013-06-05 A1 G1 J3 K0 3 HD 152884V 709 Cra 2012-07-18 A1 G1 I1 K0 1 HIP 92639 HD 155736HIP 92910 2013-06-09 A1 G1 J3 K0 3 HD 1528842011-08-07 A1 G1 I1 K0 1 HIP 93470 HD 155736V380 Ori 2010-12-22 A0 G1 I1 K0 1 HD 36134 2013-06-16 D0 G1 H0 I1 3 HD 149691HD 34863 HD 152884HIP 32076 2013-07-02 A1 B2 C1 D0 3 HD 1528842010-12-23 A0 G1 I1 K0 7 HD 220986 HD 155736HD 34863
Appendix B: PIONIER data
Article number, page 13 of 19 ig. B.1. uv plane, visibilities and closure phases for all the targets observed in this survey. For each target, the di ff erent colours representdi ff erent observing dates. The closure phase panels have di ff erent ranges, as the closure phases of each target di ff er greatly from one another. Thebaseline of the closure phases is defined at the largest baseline of the triangle. −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−50 0 50 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) AK_SCO 2011−08−06 2012−06−10 2012−07−02 2013−06−05 2013−06−09 2013−06−16 2013−07−02 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) AS_205A 2011−05−22 2012−06−10 2012−07−19 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−10−5 0 5 10 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) FK_SER 2011−05−22 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−2 0 2 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) GQ_LUP 2011−08−06 2012−07−17 . Article number, page 14 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results. −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) HN_LUP 2012−07−18 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) HT_LUP 2011−05−21 2011−05−22 2012−07−16 2013−05−12 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) MY_LUP 2012−04−16 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) RU_LUP 2011−08−07 2012−07−18 2013−05−12 . Article number, page 15 of 19
50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) RY_LUP 2011−08−07 2013−05−12 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) S_CRA 2011−08−06 2012−07−17 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−2 0 2 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) TWA_3a 2011−02−09 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−4−2 0 2 4 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) TWA_3b 2011−02−09 . Article number, page 16 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results. −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−4−2 0 2 4 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) TWA_07 2011−05−22 2012−07−18 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) TW_HYA 2011−02−09 2011−05−25 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−10−5 0 5 10 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V380_ORI 2010−12−22 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−4−2 0 2 4 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V709_CRA 2011−08−07 . Article number, page 17 of 19
50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−20 0 20 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V1000_SCO 2012−07−17 2012−08−19 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V1121_OPH 2011−08−07 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−2 0 2 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V1149_SCO 2012−07−18 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−5 0 5 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V2129_OPH 2012−04−16 2012−07−19 . Article number, page 18 of 19. Anthonioz et al.: The VLTI / PIONIER near-infrared interferometric survey of southern T Tauri stars. I. First results. −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−40−20 0 20 40 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V2508_OPH 2012−07−17 2012−07−19 2012−08−19 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−2 0 2 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) V4046_SGR 2011−08−06 . −50 0 50−50 0 50 0 20 40 60 800.00.51.0 0 20 40 60 80−100−50 0 50 100 u (M λ ) v ( M λ ) B (M λ ) V B (M λ ) T P h i ( deg ) WW_CHA 2011−02−09 2012−03−05 2012−07−01 ..