- ID:
- ivo://CDS.VizieR/J/AJ/103/983
- Title:
- Stellar occultation candidates of Saturn
- Short Name:
- J/AJ/103/983
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a list of 203 potential occultations by Saturn and its rings of stars from the Hubble Space Telescope Guide Star Catalog (GSC), during the years 1991-1999. Because the GSC is not a complete catalog, this is not an exhaustive list of Saturn occultations. In particular, stars brighter than magnitude 8 are not included. However, this list does include many fainter candidates than do current occultation candidate lists for Saturn; these fainter stars also can provide a high signal-to-noise ratio if observed with a large telescope or in the infrared where Saturn and its rings have absorption bands. We list the occultation circumstances, as well as star information found in the GSC.
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- ID:
- ivo://CDS.VizieR/J/A+A/533/A141
- Title:
- Stellar parameters for 582 HARPS FGK stars
- Short Name:
- J/A+A/533/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand the formation and evolution of solar-type stars and planets in the solar neighborhood, we need to obtain their stellar parameters with high precision. We present a catalog of precise stellar parameters for low-activity FGK single stars in a volume-limited sample followed by the HARPS spectrograph in the quest to identify extra-solar planets. The spectroscopic analysis was completed assuming LTE with a grid of Kurucz atmosphere models and using the ARES code to perform an automatic measurement of the line equivalent widths. The results are compared with different independent methods and also with other values found in the literature for common stars. Both comparisons are consistent and illustrate the homogeneity of the parameters derived by our team. The derived metallicities of this sample reveal a somewhat different distribution for the present planet hosts, but still indicates the already known higher frequency of planets observed for the more metal-rich stars. We combine the results derived in this sample with the one from the CORALIE survey to present the largest homogeneous spectroscopic study of the metallicity-giant-planet relation using a total of 1830 stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/90
- Title:
- Stellar parameters of K5 and later type Kepler stars
- Short Name:
- J/ApJ/753/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the stellar parameters of late K- and early M-type Kepler target stars. We obtain medium-resolution visible spectra of 382 stars with K_P_-J>2 (=~K5 and later spectral type). We determine luminosity class by comparing the strength of gravity-sensitive indices (CaH, K I, Ca II, and Na I) to their strength in a sample of stars of known luminosity class. We find that giants constitute 96%+/-1% of the bright (K_P_<14) Kepler target stars, and 7%+/-3% of dim (K_P_>14) stars, significantly higher than fractions based on the stellar parameters quoted in the Kepler Input Catalog (KIC). The KIC effective temperatures are systematically (110^+15^_-35_K) higher than temperatures we determine from fitting our spectra to PHOENIX stellar models. Through Monte Carlo simulations of the Kepler exoplanet candidate population, we find a planet occurrence of 0.36+/-0.08 when giant stars are properly removed, somewhat higher than when a KIC log g>4 criterion is used (0.27+/-0.05). Last, we show that there is no significant difference in g-r color (a probe of metallicity) between late-type Kepler stars with transiting Earth-to-Neptune-size exoplanet candidates and dwarf stars with no detected transits. We show that a previous claimed offset between these two populations is most likely an artifact of including a large number of misidentified giants.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/L9
- Title:
- Stellar parameters of KIC planet-host stars
- Short Name:
- J/ApJ/788/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations ("flicker") of stars can be used to measure log g to a high accuracy of ~0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag<13) candidate planet-hosting stars with T_eff_=4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/L37
- Title:
- Stellar parameters of low-mass KOIs
- Short Name:
- J/ApJ/750/L37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report stellar parameters for late-K and M-type planet-candidate host stars announced by the Kepler Mission. We obtained medium-resolution, K-band spectra of 84 cool (T_eff_<~4400K) Kepler Objects of Interest (KOIs) from Borucki et al (2011, Cat. J/ApJ/728/117). We identified one object as a giant (KOI 977); for the remaining dwarfs, we measured effective temperatures (T_eff_) and metallicities [M/H] using the K-band spectral indices of Rojas-Ayala et al (2012, Cat. J/ApJ/748/93). We determine the masses (M_*_) and radii (R_*_) of the cool KOIs by interpolation onto the Dartmouth evolutionary isochrones. The resultant stellar radii are significantly less than the values reported in the Kepler Input Catalog and, by construction, correlate better with T_eff_. Applying the published KOI transit parameters to our stellar radius measurements, we report new physical radii for the planet candidates. Recalculating the equilibrium temperatures of the planet-candidates assuming Earth's albedo and re-radiation fraction, we find that three of the planet-candidates are terrestrial sized with orbital semimajor axes that lie within the habitable zones of their host stars (KOI 463.01, KOI 812.03, and KOI 854.01).
- ID:
- ivo://CDS.VizieR/J/A+A/458/873
- Title:
- Stellar parameters of metal-rich solar-type stars
- Short Name:
- J/A+A/458/873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To date, metallicity is the only parameter of a star that appears to clearly correlate with the presence of planets and their properties. To check for new correlations between stars and the existence of an orbiting planet, we determine accurate stellar parameters for several metal-rich solar-type stars. The purpose is to fill the gap of the comparison sample presented in previous works in the high metal-content regime.
- ID:
- ivo://CDS.VizieR/J/ApJS/168/297
- Title:
- Stellar parameters of nearby cool stars
- Short Name:
- J/ApJS/168/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. We provide a catalog of physical parameters for 1074 stars that are based on a uniform set of high-quality spectral observations, a uniform spectral reduction procedure, and a uniform set of stellar evolutionary models.
- ID:
- ivo://CDS.VizieR/J/ApJ/775/L11
- Title:
- Stellar rotation periods for KOIs
- Short Name:
- J/ApJ/775/L11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large sample of stellar rotation periods for Kepler Objects of Interest, based on three years of public Kepler data. These were measured by detecting periodic photometric modulation caused by star spots, using an algorithm based on the autocorrelation function of the light curve, developed recently by McQuillan, Aigrain & Mazeh (2013). Of the 1919 main-sequence exoplanet hosts analyzed, robust rotation periods were detected for 737. Comparing the detected stellar periods to the orbital periods of the innermost planet in each system reveals a notable lack of close-in planets around rapid rotators. It appears that only slowly spinning stars with rotation periods longer than 5-10 days host planets on orbits shorter than 2 or 3 days, although the mechanism(s) that lead(s) to this is not clear.
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/1117
- Title:
- SuperWASP exoplanetary transit survey
- Short Name:
- J/MNRAS/372/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric transit surveys promise to complement the currently known sample of extra-solar planets (ESPs) by providing additional information on the planets and especially their radii. Here, we present ESP candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP North located in La Palma during the 2004 April to October observing season. The data cover fields between 23 and 03h in RA at declinations above +12{deg}. This amounts to over >>400000 stars with V magnitudes 8-13.5. For the stars brighter than 12.5, we achieve better than 1% photometric precision. Here, we present 41 sources with low-amplitude variability between >>1 and 10mmag, from which we select 12 with periods between 1.2 and 4.4d as the most promising ESP candidates. We discuss the properties of these ESP candidates, the expected fraction of transits recovered for our sample and implications for the frequency and detection of hot-Jupiters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/647
- Title:
- SuperWASP-North extrasolar planet candidates
- Short Name:
- J/MNRAS/379/647
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed photometric observations of nearly seven million stars with 8<V<15 with the SuperWASP-North instrument from La Palma between 2004 May to September. Fields in the right ascension range 17-18h, yielding over 185000 stars with sufficient quality data, have been searched for transits using a modified box least-squares (BLS) algorithm. We find a total of 58 initial transiting candidates which have high signal-to-noise ratio in the BLS, show multiple transit-like dips and have passed visual inspection. Analysis of the blending and the inferred planetary radii for these candidates leave, a total of seven transiting planet candidates which pass all the tests plus four which pass the majority. We discuss the derived parameters for these candidates and their properties and comment on the implications for future transit searches.
