W. Bhatti

HATS-4b: A dense hot Jupiter transiting a super metal-rich G star

Development of the HATSouth project was funded by NSFMRI grant NSF/AST-0723074, operations have been supported by NASA grants NNX09AB29G and NNX12AH91H, and followup observations receive partial support from grant NSF/AST- 1108686. A.J. acknowledges support from FONDECYT project 1130857, BASAL CATA PFB-06, and projects IC120009 “Millennium Institute of Astrophysics (MAS)” and P10-022-F of the Millennium Science Initiative, Chilean Ministry of Economy. R.B. and N.E. are supported by CONICYT-PCHA/Doctorado Nacional. R.B. acknowledges additional support from Nucleus P10-022-F of the Millennium Science Initiative, Chilean Ministry of Economy. V.S. acknowledges support form BASAL CATA PFB-06. M.R. acknowledges support from FONDECYT postdoctoral fellowship 3120097. Australian access to the Magellan Telescopeswas supported through the National Collaborative Research Infrastructure Strategy of the Australian Federal Government. Work at the Australian National University is supported by ARC Laureate Fellowship Grant FL0992131. We acknowledge the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the RobertMartin Ayers Sciences Fund, NASA’s Astrophysics Data System Bibliographic Services, and the SIMBADdatabase, operated at CDS, Strasbourg, France. Operations at the MPG/ESO 2.2 m Telescope are jointly performed by the Max Planck Gesellschaft and the European Southern Observatory.

The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-sized Halos

We provide a new observational test for a key prediction of the ΛCDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-sized halo growth. We perform this test by dynamically analyzing 7 galaxy clusters, spanning the redshift range 0.13 < z_c < 0.45 and caustic mass range 0.4-1.5 10^(15)h_(0.73)^(-1) M_☉, with an average of 293 spectroscopically confirmed bound galaxies to each cluster. The large radial coverage (a few virial radii), which covers the whole infall region, with a high number of spectroscopically identified galaxies enables this new study. For each cluster, we identify bound galaxies. Out of these galaxies, we identify infalling and accreted halos and estimate their masses and their dynamical states. Using the estimated masses, we derive the contribution of different mass ratios to cluster-sized halo growth. For mass ratios between ~0.2 and ~0.7, we find a ~1σ agreement with ΛCDM expectations based on the Millennium simulations I and II. At low mass ratios, ≾ 0.2, our derived contribution is underestimated since the detection efficiency decreases at low masses, ~2 × 10^(14) h_(0.73)^(-1) M_☉. At large mass ratios, ≳ 0.7, we do not detect halos probably because our sample, which was chosen to be quite X-ray relaxed, is biased against large mass ratios. Therefore, at large mass ratios, the derived contribution is also underestimated.

HATS-6b: A warm saturn transiting an early m dwarf star, and a set of empirical relations for characterizing k and m dwarf planet hosts

We report the discovery by the HATSouth survey of HATS-6b, an extrasolar planet transiting a V=15.2 mag, i=13.7 mag M1V star with a mass of 0.57 Msun and a radius of 0.57 Rsun. HATS-6b has a period of P = 3.3253 d, mass of Mp=0.32 Mjup, radius of Rp=1.00 Rjup, and zero-albedo equilibrium temperature of Teq=712.8+-5.1 K. HATS-6 is one of the lowest mass stars known to host a close-in gas giant planet, and its transits are among the deepest of any known transiting planet system. We discuss the follow-up opportunities afforded by this system, noting that despite the faintness of the host star, it is expected to have the highest K-band S/N transmission spectrum among known gas giant planets with Teq < 750 K. In order to characterize the star we present a new set of empirical relations between the density, radius, mass, bolometric magnitude, and V, J, H and K-band bolometric corrections for main sequence stars with M < 0.80 Msun, or spectral types later than K5. These relations are calibrated using eclipsing binary components as well as members of resolved binary systems. We account for intrinsic scatter in the relations in a self-consistent manner. We show that from the transit-based stellar density alone it is possible to measure the mass and radius of a ~0.6 Msun star to ~7% and ~2% precision, respectively. Incorporating additional information, such as the V-K color, or an absolute magnitude, allows the precision to be improved by up to a factor of two.

Stellar rotational periods in the planet hosting open cluster Praesepe

By using the dense coverage of the extrasolar planet survey project HATNet, we Fourier analyze 381 high-probability members of the nearby open cluster Praesepe (Beehive/M44/NGC 2632). In addition to the detection of 10 variables (of \delta Scuti and other types), we identify 180 rotational variables (including the two known planet hosts). This sample increases the number of known rotational variables in this cluster for spectral classes earlier than M by more than a factor of three. These stars closely follow a color/magnitude -- period relation from early F to late K stars. We approximate this relation by polynomials for an easier reference to the rotational characteristics in different colors. The total (peak-to-peak) amplitudes of the large majority (94%) of these variables span the range of 0.005 to 0.04 mag. The periods cover a range from 2.5 to 15 days. These data strongly confirm that Praesepe and the Hyades have the same gyrochronological ages. Regarding the two planet hosts, Pr0211 (the one with the shorter orbital period) has a rotational period that is ~2 days shorter than the one expected from the main rotational pattern in this cluster. This, together with other examples discussed in the paper, may hint that star-planet interaction via tidal dissipation can be significant in some cases in the rotational evolution of stars hosting Hot Jupiters.

HAT-P-44b, HAT-P-45b, and HAT-P-46b: Three transiting hot jupiters in possible multi-planet systems

We report the discovery by the HATNet survey of three new transiting extrasolar planets orbiting moderately bright (V = 13.2, 12.8, and 11.9) stars. The planets have orbital periods of 4.3012, 3.1290, and 4.4631 days, masses of 0.35, 0.89, and 0.49 M J, and radii of 1.24, 1.43, and 1.28 R J. The stellar hosts have masses of 0.94, 1.26, and 1.28 M ☉. Each system shows significant systematic variations in its residual radial velocities, indicating the possible presence of additional components. Based on its Bayesian evidence, the preferred model for HAT-P-44 consists of two planets, including the transiting component, with the outer planet having a period of 872 days, eccentricity of 0.494 ± 0.081, and a minimum mass of 4.0 M J. Due to aliasing we cannot rule out alternative solutions for the outer planet having a period of 220 days or 438 days. For HAT-P-45, at present there is not enough data to justify the additional free parameters included in a multi-planet model; in this case a single-planet solution is preferred, but the required jitter of 22.5 ± 6.3 m s–1 is relatively high for a star of this type. For HAT-P-46 the preferred solution includes a second planet having a period of 78 days and a minimum mass of 2.0 M J, however the preference for this model over a single-planet model is not very strong. While substantial uncertainties remain as to the presence and/or properties of the outer planetary companions in these systems, the inner transiting planets are well characterized with measured properties that are fairly robust against changes in the assumed models for the outer planets. Continued radial velocity monitoring is necessary to fully characterize these three planetary systems, the properties of which may have important implications for understanding the formation of hot Jupiters.

HATS-8b: A LOW-DENSITY TRANSITING SUPER-NEPTUNE*

HATS-8b is a low density transiting super-Neptune discovered as part of the HATSouth project. The planet orbits its solar-like G dwarf host (V=14.03

HATS9-b and HATS10-b: TWO COMPACT HOT JUPITERS in FIELD 7 of the K2 MISSION

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HATS-7b: A Hot Super Neptune Transiting a Quiet K Dwarf Star

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No Conclusive Evidence for Transits of Proxima b in MOST Photometry

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HAT-P-56b: AN INFLATED MASSIVE HOT JUPITER TRANSITING A BRIGHT F STAR FOLLOWED UP with K2 CAMPAIGN 0 OBSERVATIONS

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