69 research outputs found
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 (vsini = 9.0km/s), 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
1 km/s.Comment: 11 pages, 10 figures, submitted to A
HATS-5b: A Transiting hot-Saturn from the HATSouth Survey
We report the discovery of HATS-5b, a transiting hot-Saturn orbiting a G type
star, by the HAT-South survey. HATS-5b has a mass of Mp=0.24 Mj, radius of
Rp=0.91 Rj, and transits its host star with a period of P=4.7634d. The radius
of HATS-5b is consistent with both theoretical and empirical models. The host
star has a V band magnitude of 12.6, mass of 0.94 Msun, and radius of 0.87
Rsun. The relatively high scale height of HATS-5b, and the bright,
photometrically quiet host star, make this planet a favourable target for
future transmission spectroscopy follow-up observations. We reexamine the
correlations in radius, equilibrium temperature, and metallicity of the
close-in gas-giants, and find hot Jupiter-mass planets to exhibit the strongest
dependence between radius and equilibrium temperature. We find no significant
dependence in radius and metallicity for the close-in gas-giant population.Comment: 10 pages, submitted to A
Planets from the HATNet project
We summarize the contribution of the HATNet project to extrasolar planet
science, highlighting published planets (HAT-P-1b through HAT-P-26b). We also
briefly discuss the operations, data analysis, candidate selection and
confirmation procedures, and we summarize what HATNet provides to the exoplanet
community with each discovery.Comment: Conference proceedings at the "Detection and dynamics of transiting
exoplanets", Observatoire de Haute-Provence, 2010 August 23-2
HAT-P-47b AND HAT-P-48b: Two Low Density Sub-Saturn-Mass Transiting Planets on the Edge of the Period--Mass Desert
We report the discovery of two new transiting extrasolar planets orbiting
moderately bright (V = 10.7 and 12.2 mag) F stars (masses of 1.39 Msun and 1.10
Msun, respectively). The planets have periods of P = 4.7322 d and 4.4087 d, and
masses of 0.21 MJ and 0.17 MJ which are almost half-way between those of
Neptune and Saturn. With radii of 1.31 RJ and 1.13 RJ, these very low density
planets are the two lowest mass planets with radii in excess that of Jupiter.
Comparing with other recent planet discoveries, we find that sub-Saturns
(0.18MJ < Mp < 0.3MJ) and super-Neptunes (0.05MJ < Mp < 0.18MJ) exhibit a wide
range of radii, and their radii exhibit a weaker correlation with irradiation
than higher mass planets. The two planets are both suitable for measuring the
Rossiter-McLaughlin effect and for atmospheric characterization. Measuring the
former effect would allow an interesting test of the theory that star-planet
tidal interactions are responsible for the tendency of close-in giant planets
around convective envelope stars to be on low obliquity orbits. Both planets
fall on the edge of the short period Neptunian desert in the semi-major
axis-mass plane.Comment: Submitted to AAS Journal
HAT-P-56b: An inflated massive Hot Jupiter transiting a bright F star followed up with K2 Campaign 0 observations
We report the discovery of HAT-P-56b by the HATNet survey, an inflated hot
Jupiter transiting a bright F type star in Field 0 of NASA's K2 mission. We
combine ground-based discovery and follow-up light curves with high precision
photometry from K2, as well as ground-based radial velocities from TRES on the
FLWO 1.5m telescope to determine the physical properties of this system.
HAT-P-56b has a mass of , radius of , and transits its host
star on a near-grazing orbit with a period of 2.7908 d. The radius of HAT-P-56b
is among the largest known for a planet with . The host star has a
V-band magnitude of 10.9, mass of 1.30 , and radius of 1.43 .
The periodogram of the K2 light curve suggests the star is a Dor
variable. HAT-P-56b is an example of a ground-based discovery of a transiting
planet, where space-based observations greatly improve the confidence in the
confirmation of its planetary nature, and also improve the accuracy of the
planetary parameters.Comment: 13 pages, 11 figures, accepted by A
HAT-P-18b and HAT-P-19b: Two Low-Density Saturn-Mass Planets Transiting Metal-Rich K Stars
We report the discovery of two new transiting extrasolar planets. HAT-P-18b
orbits the V=12.759 K2 dwarf star GSC 2594-00646, with a period
P=5.508023+-0.000006 d, transit epoch Tc=2454715.02174+-0.00020 (BJD), and
transit duration 0.1131+-0.0009 d. The host star has a mass of 0.77+-0.03 Msun,
radius of 0.75+-0.04 Rsun, effective temperature 4803+-80 K, and metallicity
[Fe/H]=+0.10+-0.08. The planetary companion has a mass of 0.197+-0.013 Mjup,
and radius of 0.995+-0.052 Rjup yielding a mean density of 0.25+-0.04 g cm-3.
HAT-P-19b orbits the V=12.901 K1 dwarf star GSC 2283-00589, with a period
P=4.008778+-0.000006 d, transit epoch Tc=2455091.53417+-0.00034 (BJD), and
transit duration 0.1182+-0.0014 d. The host star has a mass of 0.84+-0.04 Msun,
radius of 0.82+-0.05 Rsun, effective temperature 4990+-130 K, and metallicity
[Fe/H]=+0.23+-0.08. The planetary companion has a mass of 0.292+-0.018 Mjup,
and radius of 1.132+-0.072 Rjup yielding a mean density of 0.25+-0.04 g cm-3.
The radial velocity residuals for HAT-P-19 exhibit a linear trend in time,
which indicates the presence of a third body in the system. Comparing these
observations with theoretical models, we find that HAT-P-18b and HAT-P-19b are
each consistent with a hydrogen-helium dominated gas giant planet with
negligible core mass. HAT-P-18b and HAT-P-19b join HAT-P-12b and WASP-21b in an
emerging group of low-density Saturn-mass planets, with negligible inferred
core masses. However, unlike HAT-P-12b and WASP-21b, both HAT-P-18b and
HAT-P-19b orbit stars with super-solar metallicity. This calls into question
the heretofore suggestive correlation between the inferred core mass and host
star metallicity for Saturn-mass planets.Comment: 18 pages, 11 figures, 9 tables. Replaced with version accepted for
publication in Ap
HAT-P-17b,c: A Transiting, Eccentric, Hot Saturn and a Long-period, Cold Jupiter
We report the discovery of HAT-P-17b,c, a multi-planet system with an inner
transiting planet in a short-period, eccentric orbit and an outer planet in a
4.8 yr, nearly circular orbit. The inner planet, HAT-P-17b, transits the bright
V = 10.54 early K dwarf star GSC 2717-00417, with an orbital period P =
10.338523 +/- 0.000009 d, orbital eccentricity e = 0.346 +/- 0.007, transit
epoch T_c = 2454801.16945 +/- 0.00020, and transit duration 0.1691 +/- 0.0009
d. HAT-P-17b has a mass of 0.530 +/- 0.018 M_J and radius of 1.010 +/- 0.029
R_J yielding a mean density of 0.64 +/- 0.05 g cm^-3. This planet has a
relatively low equilibrium temperature in the range 780-927 K, making it an
attractive target for follow-up spectroscopic studies. The outer planet,
HAT-P-17c, has a significantly longer orbital period P_2 = 1797^+58_-89 d and a
minimum mass m_2 sin i_2 = 1.4^+1.1_-0.4 M_J. The orbital inclination of
HAT-P-17c is unknown as transits have not been observed and may not be present.
The host star has a mass of 0.86 +/- 0.04 M_Sun, radius of 0.84 +/- 0.02,
effective temperature 5246 +/- 80 K, and metallicity [Fe/H] = 0.00 +/- 0.08.
HAT-P-17 is the second multi-planet system detected from ground-based transit
surveys.Comment: Submitted to ApJ, 13 pages, 6 figures, 6 table
HAT-P31bc:A Transiting, Eccentric, Hot Jupiter and a Long-Period, Massive Third Body
We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V = 11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first planet discovered with the Hungarian-made Automated Telescope (HAT) without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the HATNet project. The 2.17 M_J , 1.1 R_J planet has a period of P_b = 5.0054 days and maintains an unusually high eccentricity of e_b = 0.2450 ± 0.0045, determined through Keck, FIbr-fed Échelle Spectrograph, and Subaru high-precision radial velocities (RVs). Detailed modeling of the RVs indicates an additional quadratic residual trend in the data detected to very high confidence. We interpret this trend as a long-period outer companion, HAT-P-31c, of minimum mass 3.4 M_J and period ≥2.8 years. Since current RVs span less than half an orbital period, we are unable to determine the properties of HAT-P-31c to high confidence. However, dynamical simulations of two possible configurations show that orbital stability is to be expected. Further, if HAT-P-31c has non-zero eccentricity, our simulations show that the eccentricity of HAT-P-31b is actively driven by the presence of c, making HAT-P-31 a potentially intriguing dynamical laboratory
HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-jitter Stars
We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V = 11.289 late-F-early-G dwarf star GSC 3281-00800, with a period P = 2.150008 ± 0.000001 d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter (~80 m s^(–1)). Assuming a circular orbit, the star has a mass of 1.16 ± 0.04 M_☉ and radius of 1.22 ± 0.02 R_☉, while the planet has a mass of 0.860 ± 0.164 M_J and a radius of 1.789 ± 0.025 R_J. The second planet, HAT-P-33b, orbits the bright V = 11.188 late-F dwarf star GSC 2461-00988, with a period P = 3.474474 ± 0.000001 d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50 m s^(–1)). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ~35 m s^(–1). We find that the star has a mass of 1.38 ± 0.04 M_☉ and a radius of 1.64 ± 0.03 R_☉ while the planet has a mass of 0.762 ± 0.101 M_J and a radius of 1.686 ± 0.045 R_J for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date
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