- ID:
- ivo://CDS.VizieR/J/ApJ/724/866
- Title:
- Follow-up observations of HAT-P-15
- Short Name:
- J/ApJ/724/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-15b, a transiting extrasolar planet in the "period valley," a relatively sparsely populated period regime of the known extrasolar planets. The host star, GSC 2883-01687, is a G5 dwarf with V=12.16. It has a mass of 1.01+/-0.04M_{sun}_, radius of 1.08+/-0.04R_{sun}_, effective temperature 5568+/-90K, and metallicity [Fe/H]=+0.22+/-0.08. The planetary companion orbits the star with a period P=10.863502+/-0.000027 days, transit epoch T_c_=2454638.56019+/-0.00048(BJD), and transit duration 0.2285+/-0.0015days. It has a mass of 1.946+/-0.066M_J_ and radius of 1.072+/-0.043R_J_ yielding a mean density of 1.96+/-0.22g/cm^3^. At an age of 6.8^+2.5^_-1.6_Gyr, the planet is H/He-dominated and theoretical models require about 2% (10M_{earth}_) worth of heavy elements to reproduce its measured radius. With an estimated equilibrium temperature of ~820K during transit, and ~1000K at occultation, HAT-P-15b is a potential candidate to study moderately cool planetary atmospheres by transmission and occultation spectroscopy.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/152/136
- Title:
- Follow-up photometry and spectroscopy of KELT-17
- Short Name:
- J/AJ/152/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of a hot Jupiter transiting the V=9.23mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a 1.31_-0.29_^+0.28^M_J_, 1.525_-0.060_^+0.065^R_J_ hot-Jupiter in a 3.08-day period orbit misaligned at -115.9{deg}+/-4.1{deg} to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet during two transits. The nature of the spin-orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with both rigid-body rotation and solar differential rotation rates ({alpha}<0.30 at 2{sigma} significance). KELT-17 is only the fourth A-star with a confirmed transiting planet, and with a mass of 1.635_-0.061_^+0.066^M_{Sun}_, an effective temperature of 7454+/-49K, and a projected rotational velocity of vsinI_*_=44.2_-1.3_^+1.5^km/s; it is among the most massive, hottest, and most rapidly rotating of known planet hosts.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/84
- Title:
- Follow-up photometry and velocity of Qatar 2
- Short Name:
- J/ApJ/750/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short period, P_b_= 1.34 days. The mass and radius of Qatar-2b are M_P_ = 2.49 M_J_ and R_P_= 1.14 R_J_, respectively. Radial-velocity monitoring of Qatar-2 over a span of 153 days revealed the presence of a second companion in an outer orbit. The Systemic Console yielded plausible orbits for the outer companion, with periods on the order of a year and a companion mass of at least several M_J_. Thus, Qatar-2 joins the short but growing list of systems with a transiting hot Jupiter and an outer companion with a much longer period. This system architecture is in sharp contrast to that found by Kepler for multi-transiting systems, which are dominated by objects smaller than Neptune, usually with tightly spaced orbits that must be nearly coplanar.
- ID:
- ivo://CDS.VizieR/J/ApJ/710/1724
- Title:
- Follow-up photometry for HAT-P-11
- Short Name:
- J/ApJ/710/1724
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the discovery of HAT-P-11b, the smallest radius transiting extrasolar planet (TEP) discovered from the ground, and the first hot Neptune discovered to date by transit searches. HAT-P-11b orbits the bright (V=9.587) and metal rich ([Fe/H]=+0.31+/-0.05) K4 dwarf star GSC 03561-02092 with P=4.8878162+/-0.0000071 days and produces a transit signal with depth of 4.2mmag, the shallowest found by transit searches that is due to a confirmed planet. We present a global analysis of the available photometric and radial velocity (RV) data that result in stellar and planetary parameters, with simultaneous treatment of systematic variations. HAT-P-11b orbits in an eccentric orbit with e=0.198+/-0.046 and {omega}=355.2{deg}+/-17.3{deg}, causing a reflex motion of its parent star with amplitude 11.6+/-1.2m/s, a challenging detection due to the high level of chromospheric activity of the parent star. Our ephemeris for the transit events is T_c_=2454605.89132+/-0.00032 (BJD), with duration 0.0957+/-0.0012 days, and secondary eclipse epoch of 2454608.96+/-0.15 days (BJD).
- ID:
- ivo://CDS.VizieR/J/AJ/144/19
- Title:
- Follow-up photometry for HAT-P-34 through HAT-P-37
- Short Name:
- J/AJ/144/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four transiting extrasolar planets (HAT-P-34b-HAT-P-37b) with masses ranging from 1.05 to 3.33M_J_ and periods from 1.33 to 5.45days. 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 (3.33M_J_), has a high eccentricity of e=0.441+/-0.032 at a period of P=5.452654+/-0.000016days, and shows hints of an outer component. The other three planets have properties that are typical of hot Jupiters.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/138
- Title:
- Follow-up photometry of HAT-P-26
- Short Name:
- J/ApJ/728/138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-26b, a transiting extrasolar planet orbiting the moderately bright V=11.744 K1 dwarf star GSC 0320-01027, with a period P=4.234516+/-0.000015 days, transit epoch T_c_=2455304.65122+/-0.00035 (BJD; Barycentric Julian dates throughout the paper are calculated from Coordinated Universal Time (UTC)), and transit duration 0.1023+/-0.0010 days. The host star has a mass of 0.82+/-0.03M_{sun}_, radius of 0.79^+0.10^_-0.04_R_{sun}_, effective temperature 5079+/-88K, and metallicity [Fe/H]=-0.04+/-0.08. The planetary companion has a mass of 0.059+/-0.007M_J_, and radius of 0.565^+0.072^_-0.032_R_J_ yielding a mean density of 0.40+/-0.10g/cm^3^. HAT-P-26b is the fourth Neptune-mass transiting planet discovered to date. It has a mass that is comparable to those of Neptune and Uranus, and slightly smaller than those of the other transiting Super-Neptunes, but a radius that is ~65% larger than those of Neptune and Uranus, and also larger than those of the other transiting Super-Neptunes. HAT-P-26b is consistent with theoretical models of an irradiated Neptune-mass planet with a 10M_{earth}_ heavy element core that comprises >~50% of its mass with the remainder contained in a significant hydrogen-helium envelope, though the exact composition is uncertain as there are significant differences between various theoretical models at the Neptune-mass regime. The equatorial declination of the star makes it easily accessible to both Northern and Southern ground-based facilities for follow-up observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/734/109
- Title:
- Follow-up photometry of HAT-P-27
- Short Name:
- J/ApJ/734/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-27b, an exoplanet transiting the moderately bright G8 dwarf star GSC 0333-00351 (V=12.214). The orbital period is 3.039586+/-0.000012 days, the reference epoch of transit is 2455186.01879+/-0.00054 (BJD), and the transit duration is 0.0705+/-0.0019 days. The host star with its effective temperature 5300+/-90K is somewhat cooler than the Sun and is more metal-rich with a metallicity of +0.29+/-0.10. Its mass is 0.94+/-0.04M_{sun}_ and radius is 0.90^+0.05^_-0.04_R_{sun}_. For the planetary companion we determine a mass of 0.660+/-0.033M_J_ and radius of 1.038^+0.077^_-0.058_R_J_. For the 30 known transiting exoplanets between 0.3M_J_ and 0.8M_J_, a negative correlation between host star metallicity and planetary radius and an additional dependence of planetary radius on equilibrium temperature are confirmed at a high level of statistical significance.
- ID:
- ivo://CDS.VizieR/J/AJ/145/5
- Title:
- Follow-up photometry of HATS-1
- Short Name:
- J/AJ/145/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-1b, a transiting extrasolar planet orbiting the moderately bright V=12.05 G dwarf star GSC 6652-00186, and the first planet discovered by HATSouth, a global network of autonomous wide-field telescopes. HATS-1b has a period of P{approx}3.4465days, mass of M_p_{approx}1.86M_J_, and radius of R_p_{approx}1.30R_J_. The host star has a mass of 0.99M_{sun}_ and radius of 1.04R_{sun}_. The discovery light curve of HATS-1b has near-continuous coverage over several multi-day timespans, demonstrating the power of using a global network of telescopes to discover transiting planets.
- ID:
- ivo://CDS.VizieR/J/A+A/596/A47
- Title:
- FORS2 transmission spectroscopy of WASP-17b
- Short Name:
- J/A+A/596/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present FORS2 (attached to ESO's Very Large Telescope) observations of the exoplanet WASP-17b during its primary transit, for the purpose of differential spectrophotometry analysis. We use the instrument in its Mask eXchange Unit (MXU) mode to simultaneously obtain low resolution spectra of the planet hosting star, as well as several reference stars in the field of view. The integration of these spectra within broadband and smaller 100{AA} bins provides us with 'white' and spectrophotometric light curves, from 5700 to 8000{AA}. Through modelling the white light curve, we obtain refined bulk and transit parameters of the planet, as well as wavelength-dependent variations of the planetary radius from smaller spectral bins through which the transmission spectrum is obtained. The inference of transit parameters, as well as the noise statistics, is performed using a Gaussian Process model. We achieve a typical precision in the transit depth of a few hundred parts per million from various transit light curves. From the transmission spectra we rule out a flat spectrum at >3{sigma} and detect marginal presence of the pressure-broadened sodium wings. Furthermore, we detect the wing of the potassium absorption line in the upper atmosphere of the planet with 3-{sigma} confidence, both facts pointing to a relatively shallow temperature gradient in the atmosphere. These conclusions are mostly consistent with previous studies of this exo-atmosphere, although previous potassium measurements have been inconclusive.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A131
- Title:
- Four Jovian planets RV and activity indexes
- Short Name:
- J/A+A/646/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of planetary companions orbiting four low-luminosity giant stars with M* between 1.04 and 1.39M_{sun}_. All four host stars have been independently observed by the EXoPlanets aRound Evolved StarS (EXPRESS) program and the Pan-Pacific Planet Search (PPPS). The companion signals were revealed by multi-epoch precision radial velocities obtained in nearly a decade. The planetary companions exhibit orbital periods between ~1.2 and 7.1 years, minimum masses of m_p_*sini~1.8-3.7M_Jup_, and eccentricities between 0.08 and 0.42. With these four new systems, we have detected planetary companions to 11 out of the 37 giant stars that are common targets in the EXPRESS and PPPS. After excluding four compact binaries from the common sample, we obtained a fraction of giant planets (m_p_~1-2M_Jup_) orbiting within 5AU from their parent star of f=33.3^+9.0^_-7.1_%. This fraction is slightly higher than but consistent at the 1{sigma} level with previous results obtained by different radial velocity surveys. Finally, this value is substantially higher than the fraction predicted by planet formation models of gas giants around stars more massive than the Sun.
