K. Penev

CONSTRAINING TIDAL DISSIPATION IN STARS FROM THE DESTRUCTION RATES OF EXOPLANETS

We use the distribution of extrasolar planets in circular orbits around stars with surface convective zones detected by ground-based transit searches to constrain how efficiently tides raised by the planet are dissipated on the parent star. We parameterize this efficiency as a tidal quality factor (Q *). We conclude that the population of currently known planets is inconsistent with Q * < 107 at the 99% level. Previous studies show that values of Q * between 105 and 107 are required in order to explain the orbital circularization of main-sequence low-mass binary stars in clusters, suggesting that different dissipation mechanisms might be acting in the two cases, most likely due to the very different tidal forcing frequencies relative to the stellar rotation frequency occurring for star-star versus planet-star systems.

HAT-P-39b–HAT-P-41b: Three Highly Inflated Transiting Hot Jupiters

We report the discovery of three new transiting extrasolar planets orbiting moderately bright (V = 11.1, 11.7, and 12.4) F stars. The planets HAT-P-39b through HAT-P-41b have periods of P = 3.5439 days, 4.4572 days, and 2.6940 days, masses of 0.60 M_J, 0.62 M_J, and 0.80 M_J, and radii of 1.57 R_J, 1.73 R_J, and 1.68 R_J, respectively. They orbit stars with masses of 1.40 M_☉, 1.51 M_☉, and 1.51 M_☉, respectively. The three planets are members of an emerging population of highly inflated Jupiters with 0.4 M_J 1.5 R_J.

On Dissipation inside Turbulent Convection Zones from Three-dimensional Simulations of Solar Convection

The development of two-dimensional and three-dimensional simulations of solar convection has lead to a picture of convection quite unlike the usually assumed Kolmogorov spectrum turbulent flow. We investigate the impact of this changed structure on the dissipation properties of the convection zone, parameterized by an effective viscosity coefficient. We use an expansion treatment developed by Goodman & Oh, applied to a numerical model of solar convection, to calculate effective viscosity as a function of frequency and compare this to currently existing prescriptions based on the assumption of Kolmogorov turbulence. The results quite closely match a linear scaling with period, even though this same formalism applied to a Kolmogorov spectrum of eddies gives a scaling with a power-law index of 5/3.

HAT-P-34b-HAT-P-37b: FOUR TRANSITING PLANETS MORE MASSIVE THAN JUPITER ORBITING MODERATELY BRIGHT STARS*

We report the discovery of four transiting extrasolar planets (HAT-P-34b–HAT-P-37b) with masses ranging from 1.05 to 3.33 M_J and periods from 1.33 to 5.45 days. These planets orbit relatively bright F and G dwarf stars (from V = 10.16 to V = 13.2). Of particular interest is HAT-P-34b which is moderately massive (3.33 M_J), has a high eccentricity of e = 0.441 ± 0.032 at a period of P = 5.452654 ± 0.000016 days, and shows hints of an outer component. The other three planets have properties that are typical of hot Jupiters.

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.

HATS-3b: An inflated hot Jupiter transiting an F-type star

We report the discovery by the HATSouth survey of HATS-3b, a transiting extrasolar planet orbiting a V=12.4 F dwarf star. HATS-3b has a period of P = 3.5479d, mass of Mp = 1.07MJ, and radius of Rp = 1.38RJ. Given the radius of the planet, the brightness of the host star, and the stellar rotational velocity (v sini = 9.0kms −1 ), this system will make an interesting target for future observations to measure the Rossiter-McLaughlin effect and determine its spin-orbit alignment. We detail the low/medium-resolution reconnaissance spectroscopy that we are now using to deal with large numbers of transiting planet candidates produced by the HATSouth survey. We show that this important step in discovering planets produces logg and Teff parameters at a precision suitable for efficient candidate vetting, as well as efficiently identifying stellar mass eclipsing binaries with radial velocity semi-amplitudes as low as 1kms −1 . Subject headings: planetary systems — stars: individual (HATS-3, GSC 6926-00454) techniques: spectroscopic, photometric

The mass-radius relationship for very low mass stars: Four new discoveries from the HATSouth Survey

Development of the HATSouth project was funded by NSF MRI grant NSF/AST-0723074, operations are supported by NASA grant NNX09AB29G and follow-up observations receive partial support from grant NSF/AST-1108686. Work at the Australian National University is supported by ARC Laureate Fellowship Grant FL0992131. Follow-up observations with the ESO 2.2 m/FEROS instrument were performed under MPI guaranteed time [P087.A9014(A), P088.A-9008(A), P089.A-9008(A)]. AJ acknowledges support from FONDECYT project 1130857, BASAL CATA PFB06 and the Millenium Science Initiative, Chilean Ministry of Economy (Nuclei: P10-022-F, P07-021-F). RB and NE are supported by CONICYT-PCHA/Doctorado Nacional and MR is supported by FONDECYT postdoctoral fellowship 3120097. We acknowledge the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund, and the SIMBAD data base, 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.

KELT-3b: A HOT JUPITER TRANSITING A V = 9.8 LATE-F STAR

We report the discovery of KELT-3b, a moderately inflated transiting hot Jupiter with a mass of 1.477 +0.066 −0.067 MJ, radius of 1.345 ± 0.072 RJ, and an orbital period of 2.7033904 ± 0.000010 days. The host star, KELT-3, is a V = 9.8 late F star with M∗ = 1.278 +0.063 −0.061 M� , R∗ = 1.472 +0.065 −0.067 R� , Teff = 6306 +5049 K, log(g) = 4.209 +0.033 −0.031, and [Fe/H] = 0.044 +0.080 −0.082 , and has a likely proper motion companion. KELT-3b is the third transiting exoplanet discovered by the KELT survey, and is orbiting one of the 20 brightest known transiting planet host stars, making it a promising candidate for detailed characterization studies. Although we infer that KELT-3 is significantly evolved, a preliminary analysis of the stellar and orbital evolution of the system suggests that the planet has likely always received a level of incident flux above the empirically identified threshold for radius inflation suggested by Demory & Seager.

Long-Term Solar Variability and the Solar Cycle in the 21st Century

We have examined the long-term trends in the solar variability that can be deduced from some indirect data and from optical records. We analyzed the radiocarbon measurements for the last 4500 years, based on dendrochronology, the Schove series for the last 1700 years, based on auroral records, and the Hoyt-Schatten series of group sunspot numbers. Focusing on periodicities near one and two centuries, which most likely have a solar origin, we conclude that the present epoch is at the onset of an upcoming local minimum in the long-term solar variability. There are some clues that the next minimum will be less deep than the Maunder minimum, but ultimately the relative depth between these two minima will be indicative of the amplitude change of the quasi-two-century solar cycle.

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.