- ID:
- ivo://CDS.VizieR/J/ApJ/779/188
- Title:
- Spectra of nearby late K and M Kepler stars
- Short Name:
- J/ApJ/779/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities. We use these revised values to calibrate spectroscopic techniques to infer the fundamental parameters of more distant late-type dwarf stars. We demonstrate that, after masking out poorly modeled regions, the newest version of the PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. We apply methods to late-type hosts of transiting planet candidates in the Kepler field, and calculate effective temperature, radius, mass, and luminosity with typical errors of 57K, 7%, 11%, and 13%, respectively. We find systematic offsets between our values and those from previous analyses of the same stars, which we attribute to differences in atmospheric models utilized for each study. We investigate which of the planets in this sample are likely to orbit in the circumstellar habitable zone. We determine that four candidate planets (KOI 854.01, 1298.02, 1686.01, and 2992.01) are inside of or within 1{sigma} of a conservative definition of the habitable zone, but that several planets identified by previous analyses are not (e.g., KOI 1422.02 and KOI 2626.01). Only one of the four habitable-zone planets is Earth sized, suggesting a downward revision in the occurrence of such planets around M dwarfs. These findings highlight the importance of measuring accurate stellar parameters when deriving parameters of their orbiting planets.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/557/L6
- Title:
- Spectra of the Titan haze at 1-5 micron
- Short Name:
- J/A+A/557/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We retrieved optical-depth spectra of the Titanian haze in the range 1-5um from solar occultation data obtained by the Cassini/Visual Infrared Mapping Spectrometer (VIMS) at altitudes of 59-502km. Only limited wavelength intervals within this spectral range have been analyzed before. The haze spectra we retrieved are mostly similar to those of alkane particles (or powders), with three major absorption peaks typical of alkane powders at 2.3, 3.4, and 4.3um.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/1145
- Title:
- Spectrophotometry of TrES-3 and TrES-4
- Short Name:
- J/ApJ/691/1145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report new spectroscopic and photometric observations of the parent stars of the recently discovered transiting planets TrES-3 and TrES-4. A detailed abundance analysis based on high-resolution spectra yields [Fe/H]=-0.19+/-0.08, Teff=5650+/-75K, and logg=4.4+/-0.1 for TrES-3, and [Fe/H]=+0.14+/-0.09, Teff=6200+/-75K, and logg=4.0+/-0.1 for TrES-4. The accuracy of the effective temperatures is supported by a number of independent consistency checks. The spectroscopic orbital solution for TrES-3 is improved with our new radial velocity measurements of that system, as are the light-curve parameters for both systems based on newly acquired photometry for TrES-3 and a reanalysis of existing photometry for TrES-4. With these revised stellar parameters, we obtain improved values for the planetary masses and radii. We find M_p_=1.910^+0.075^_-0.080_M_Jup_, R_p_=1.336^+0.031^_-0.036_R_Jup_ for TrES-3, and M_p_=0.925+/-0.082M_Jup_, R_p_=1.783^+0.093^_-0.086_R_Jup_ for TrES-4. We confirm TrES-4 as the planet with the largest radius among the currently known transiting hot Jupiters.
- ID:
- ivo://CDS.VizieR/J/A+A/482/989
- Title:
- Spectropolarimetric model for Earth-like planets
- Short Name:
- J/A+A/482/989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of numerical simulations of flux F and degree of polarization P of light that is reflected by Earth-like extrasolar planets orbiting solar type stars. Our results are presented as functions of the wavelength (from 0.3 to 1.0{mu}m, with 0.001{mu}m spectral resolution) and as functions of the planetary phase angle. We use different surface coverages for our model planets, including vegetation and a Fresnel reflecting ocean, and clear and cloudy atmospheres.
- ID:
- ivo://CDS.VizieR/J/ApJ/770/43
- Title:
- Spectroscopic [Fe/H] of Kepler stars
- Short Name:
- J/ApJ/770/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been shown that F, G, and early K dwarf hosts of Neptune-sized planets are not preferentially metal-rich. However, it is less clear whether the same holds for late K and M dwarf planet hosts. We report metallicities of Kepler targets and candidate transiting planet hosts with effective temperatures below 4500K. We use new metallicity calibrations to determine [Fe/H] from visible and near-infrared spectra. We find that the metallicity distribution of late K and M dwarfs monitored by Kepler is consistent with that of the solar neighborhood. Further, we show that hosts of Earth- to Neptune-sized planets have metallicities consistent with those lacking detected planets and rule out a previously claimed 0.2dex offset between the two distributions at 6{sigma} confidence. We also demonstrate that the metallicities of late K and M dwarfs hosting multiple detected planets are consistent with those lacking detected planets. Our results indicate that multiple terrestrial and Neptune-sized planets can form around late K and M dwarfs with metallicities as low as 0.25 solar. The presence of Neptune-sized planets orbiting such low-metallicity M dwarfs suggests that accreting planets collect most or all of the solids from the disk and that the potential cores of giant planets can readily form around M dwarfs. The paucity of giant planets around M dwarfs compared to solar-type stars must be due to relatively rapid disk evaporation or a slower rate of planet accretion, rather than insufficient solids to form a core.
- ID:
- ivo://CDS.VizieR/J/A+A/487/373
- Title:
- Spectroscopic parameters of 451 HARPS-GTO stars
- Short Name:
- J/A+A/487/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand the formation and evolution of solar-type stars in the solar neighborhood, we need to measure their stellar parameters to high accuracy. We present a catalogue of accurate stellar parameters for 451 stars that represent the HARPS Guaranteed Time Observations (GTO) "high precision" sample. Spectroscopic stellar parameters were measured using high signal-to-noise (S/N) spectra acquired with the HARPS spectrograph. The spectroscopic analysis was completed assuming LTE with a grid of Kurucz atmosphere models and the recent ARES code for measuring line equivalent widths. We show that our results agree well with those ones presented in the literature (for stars in common). We present a useful calibration for the effective temperature as a function of the index color B-V and [Fe/H]. We use our results to study the metallicity-planet correlation, namely for very low mass planets. The results presented here suggest that in contrast to their jovian counterparts, Neptune-like planets do not form preferentially around metal-rich stars. The ratio of Jupiter-to-Neptune is also an increasing function of stellar metallicity. These results are discussed in the context of the core-accretion model for planet formation.
- ID:
- ivo://CDS.VizieR/J/AJ/148/29
- Title:
- Spectroscopy and differential photometry of HATS-4
- Short Name:
- J/AJ/148/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by the HATSouth survey of HATS-4b, an extrasolar planet transiting a V=13.46mag G star. HATS-4b has a period of P{approx}2.5167days, mass of M_p_{approx}1.32M_Jup_, radius of R_p_{approx}1.02R_Jup_, and density of {rho}_p_=1.55+/-0.16g/cm3{approx}1.24{rho}_Jup_. The host star has a mass of 1.00 M_{sun}_, a radius of 0.92 R_{sun}_, and a very high metallicity [Fe/H]=0.43+/-0.08. HATS-4b is among the densest known planets with masses between 1 and 2M_J_ and is thus likely to have a significant content of heavy elements of the order of 75M_{oplus}_. In this paper we present the data reduction, radial velocity measurements, and stellar classification techniques adopted by the HATSouth survey for the CORALIE spectrograph. We also detail a technique for simultaneously estimating vsini and macroturbulence using high resolution spectra.
- ID:
- ivo://CDS.VizieR/J/AJ/150/168
- Title:
- Spectroscopy and photometry for HAT-P-50--HAT-P-53
- Short Name:
- J/AJ/150/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35M_J_ and radius of 1.29R_J_, and orbits a bright (V=11.8mag) M=1.27M_{sun}_, R=1.70R_{sun}_ star every P=3.1220days. The planet HAT-P-51b has a mass of 0.31M_J_ and radius of 1.29R_J_, and orbits a V=13.4mag, M=0.98M_{sun}_, R=1.04R_{sun}_ star with a period of P=4.2180days. The planet HAT-P-52b has a mass of 0.82M_J_ and radius of 1.01R_J_, and orbits a V=14.1mag, M=0.89M_{sun}_, R=0.89R_{sun}_ star with a period of P=2.7536days. The planet HAT-P-53b has a mass of 1.48M_J_ and radius of 1.32R_J_, and orbits a V=13.7mag, M=1.09M_{sun}_, R=1.21R_{sun}_ star with a period of P=1.9616days. All four planets are consistent with having circular orbits and have masses and radii measured to better than 10% precision. The low stellar jitter and favorable R_p_/R_{star}_ ratio for HAT-P-51 make it a promising target for measuring the Rossiter-McLaughlin effect for a Saturn-mass planet.
- ID:
- ivo://CDS.VizieR/J/AJ/151/89
- Title:
- Spectroscopy and photometry of HATS-17
- Short Name:
- J/AJ/151/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-17b, the first transiting warm Jupiter of the HATSouth network. HATS-17b transits its bright (V=12.4) G-type (M_{star}_=1.131+/-0.030M_{sun}_, R_{star}_=1.090_-0.046_^+0.070^) metal-rich ([Fe/H]=+0.3dex) host star in a circular orbit with a period of P=16.2546days. HATS-17b has a very compact radius of 0.777+/-0.056R_J_ given its Jupiter-like mass of 1.338+/-0.065M_J_. Up to 50% of the mass of HATS-17b may be composed of heavy elements in order to explain its high density with current models of planetary structure. HATS-17b is the longest period transiting planet discovered to date by a ground-based photometric survey, and is one of the brightest transiting warm Jupiter systems known. The brightness of HATS-17 will allow detailed follow-up observations to characterize the orbital geometry of the system and the atmosphere of the planet.
- ID:
- ivo://CDS.VizieR/J/AJ/152/88
- Title:
- Spectroscopy and photometry of HATS-11 and HATS-12
- Short Name:
- J/AJ/152/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V=14.1 G0-star shows a periodic 12.9mmag dip in its light curve every 3.6192days and a radial velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of 1.000+/-0.060M_{Sun}_, a radius of 1.444+/-0.057R_{Sun}_ and an effective temperature of 6060+/-150K, while its companion is a 0.85+/-0.12M_J_, 1.510+/-0.078R_J_ planet in a circular orbit. HATS-12 shows a periodic 5.1mmag flux decrease every 3.1428days and Keplerian radial velocities variations around a V=12.8 F-star. HATS-12 has a mass of 1.489+/-0.071M_{Sun}_, a radius of 2.21+/-0.21R_{Sun}_, and an effective temperature of 6408+/-75K. For HATS-12b, our measurements indicate that this is a 2.38+/-0.11M_J_, 1.35+/-0.17R_J_ planet in a circular orbit. Both host stars show subsolar metallicities of -0.390+/-0.060dex and -0.100+/-0.040dex, respectively, and are (slightly) evolved stars. In fact, HATS-11 is among the most metal-poor and, HATS-12, with a logg_*_ of 3.923+/-0.065, is among the most evolved stars hosting a hot-Jupiter planet. Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively).