- ID:
- ivo://CDS.VizieR/J/ApJ/801/3
- Title:
- Rotation periods for Q3-Q14 KOIs
- Short Name:
- J/ApJ/801/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed amplitude of the rotational photometric modulation of a star with spots should depend on the inclination of its rotational axis relative to our line of sight. Therefore, the distribution of observed rotational amplitudes of a large sample of stars depends on the distribution of their projected axes of rotation. Thus, comparison of the stellar rotational amplitudes of the Kepler objects of interest (KOIs) with those of Kepler single stars can provide a measure to indirectly infer the properties of the spin-orbit obliquity of Kepler planets. We apply this technique to the large samples of 993 KOIs and 33614 single Kepler stars in temperature range of 3500-6500K. We find with high significance that the amplitudes of cool KOIs are larger, on the order of 10%, than those of the single stars. In contrast, the amplitudes of hot KOIs are systematically lower. After correcting for an observational bias, we estimate that the amplitudes of the hot KOIs are smaller than the single stars by about the same factor of 10%. The border line between the relatively larger and smaller amplitudes, relative to the amplitudes of the single stars, occurs at about 6000K. Our results suggest that the cool stars have their planets aligned with their stellar rotation, while the planets around hot stars have large obliquities, consistent with the findings of Winn et al. (2010ApJ...718L.145W) and Albrecht et al. (2012, J/ApJ/757/18). We show that the low obliquity of the planets around cool stars extends up to at least 50 days, a feature that is not expected in the framework of a model that assumes the low obliquity is due to planet-star tidal realignment.
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- ID:
- ivo://CDS.VizieR/J/AJ/151/117
- Title:
- R photometry of (225088) 2007 OR_10_
- Short Name:
- J/AJ/151/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first comprehensive thermal and rotational analysis of the second most distant trans-Neptunian object (TNOs) (225088)2007OR_10_. We combined optical light curves provided by the Kepler Space Telescope-K2 extended mission and thermal infrared data provided by the Herschel Space Observatory. We found that (225088)2007OR_10_ is likely to be larger and darker than derived by earlier studies: we obtained a diameter of d=1535_-225_^+75^km which places (225088) 2007OR_10_ in the biggest top three TNOs. The corresponding visual geometric albedo is p_V_=0.089_-0.009_^+0.031^. The light-curve analysis revealed a slow rotation rate of P_rot_=44.81+/-0.37hr, superseded by very few objects. The most likely light-curve solution is double-peaked with a slight asymmetry; however, we cannot safely rule out the possibility of having a rotation period of P_rot_=22.40+/-0.18hr, which corresponds to a single-peaked solution. Due to the size and slow rotation, the shape of the object should be a MacLaurin ellipsoid, so the light variation should be caused by surface inhomogeneities. Its newly derived larger diameter also implies larger surface gravity and a more likely retention of volatiles--CH_4_, CO, and N_2_--on the surface.
- ID:
- ivo://CDS.VizieR/J/A+A/567/A14
- Title:
- RV and g'z' transits of KOI-1089b/Kepler-418b
- Short Name:
- J/A+A/567/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1M_jup_ on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~40% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110+/-0.0025, more than 25% more than the 0.087 measured by Kepler, leading to a radius of 1.20+/-0.16R_jup_ instead of the 0.94R_jup_ measured by the Kepler team. This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors and binary companions that do not affect the classification of the transiting object but can have a very significant effect on the perceived planetary radius.
- ID:
- ivo://CDS.VizieR/J/A+A/499/935
- Title:
- RV curves of 42 Dra and HD 139357
- Short Name:
- J/A+A/499/935
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the past 3 years we have been monitoring 62 K giant stars using precise stellar radial velocity (RV) measurements with the 2m Alfred Jensch Telescope of the Thuringer Landessternwarte Tautenburg (TLS). To probe the dependence of planet formation on stellar mass by finding planets around intermediate-mass giant stars. We present high accuracy RV measurements of the K1.5 III star 42 Dra and the K4 III star HD 139357. The wavelength reference for the RV measurements was provided by an iodine absorption cell placed in the optical path of the spectrograph.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/1503
- Title:
- RV curves of WASP-16, 25 and 31
- Short Name:
- J/MNRAS/423/1503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new measurements of the Rossiter-McLaughlin (RM) effect for three Wide Angle Search for transiting Planets (WASP) planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of their complete sets of photometric and spectroscopic data.
- ID:
- ivo://CDS.VizieR/J/A+A/496/513
- Title:
- RV of 6 stars with long-period giant planets
- Short Name:
- J/A+A/496/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of six new substellar companions of main-sequence stars, detected by multiple Doppler measurements with the instrument HARPS installed on the ESO 3.6m telescope, La Silla, Chile. These extrasolar planets orbit the stars BD-17 0063, HD 20868, HD 73267, HD 131664, HD 145377, and HD 153950. The orbital characteristics that reproduce the observed data are presented, as well as the stellar and planetary parameters. Masses of the companions range from 2 to 18 Jupiter masses, and periods range from 100 to 2000 days. The observational data are carefully analysed for activity-induced effects, and we conclude that the observed radial velocity variations are of exoplanetary origin. Of particular interest is the very massive planet (or brown-dwarf companion) orbiting the metal-rich HD 131664 with m_2_sini=18.15M_{Jup}_ and a 5.34-year orbital period. These new discoveries are consistent with the observed statistical properties of exoplanet samples known so far.
- ID:
- ivo://CDS.VizieR/J/ApJ/746/36
- Title:
- RV standard deviation in the M2K survey
- Short Name:
- J/ApJ/746/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We constrain the densities of Earth- to Neptune-size planets around very cool (T_e_=3660-4660K) Kepler stars by comparing 1202 Keck/HIRES radial velocity measurements of 150 nearby stars to a model based on Kepler candidate planet radii and a power-law mass-radius relation. Our analysis is based on the presumption that the planet populations around the two sets of stars are the same. The model can reproduce the observed distribution of radial velocity variation over a range of parameter values, but, for the expected level of Doppler systematic error, the highest Kolmogorov-Smirnov probabilities occur for a power-law index {alpha}{approx}4, indicating that rocky-metal planets dominate the planet population in this size range. A single population of gas-rich, low-density planets with {alpha}=2 is ruled out unless our Doppler errors are >=5m/s, i.e., much larger than expected based on observations and stellar chromospheric emission. If small planets are a mix of {gamma} rocky planets ({alpha}=3.85) and 1-{gamma} gas-rich planets ({alpha}=2), then {gamma}>0.5 unless Doppler errors are >=4m/s. Our comparison also suggests that Kepler's detection efficiency relative to ideal calculations is less than unity. One possible source of incompleteness is target stars that are misclassified subgiants or giants, for which the transits of small planets would be impossible to detect. Our results are robust to systematic effects, and plausible errors in the estimated radii of Kepler stars have only moderate impact.
- ID:
- ivo://CDS.VizieR/J/A+A/380/727
- Title:
- 1995 Saturnian satellite observations
- Short Name:
- J/A+A/380/727
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper provides an analysis of astrometric measurements of the main Saturnian satellites made thanks to CCD observations performed in 1995 at the Laboratorio Nacional de Astrofisica at Itajuba in Brazil. The astrometric reduction is discussed, especially the small corrections done here, but most of time neglected elsewhere. A catalog of 6006 differential positions has been obtained. They have been compared to different ephemerides, the Vienne & Duriez ephemerides (TASS 1.7, 1995A&A...297..588V, 1997 Cat. <J/A+A/324/366>), the Harper & Taylor (1994A&A...284..619H) ephemerides and the Dourneau (1993A&A...267..292D) ephemerides. These observations provide a large set of modern observations, and appear to be of good precision. This accuracy is needed for future use of these data to improve the dynamical models. These positions are included in the data base NSDC dedicated to the natural satellites (ftp://ftp.bdl.fr/pub/NSDC/saturn/raw_data/position/).
- ID:
- ivo://CDS.VizieR/J/A+A/610/A2
- Title:
- Saturnian satellites Cassini ISS astrometry
- Short Name:
- J/A+A/610/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Caviar is a software package designed for the astrometric measurement of natural satellite positions in images taken using the Imaging Science Subsystem (ISS) of the Cassini spacecraft. We provide new astrometric positions for selected major satellites of Saturn, 2013-2016.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A76
- Title:
- Saturnian satellites in the Gaia ref. frame
- Short Name:
- J/A+A/645/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a remeasurement of old photographic plates, providing important raw data for dynamical studies of the Saturnian satellite system. The unprecedentedly accurate realization of the Gaia reference frame allows us to make a precise calibration of digitized astronegatives of the Saturnian satellite images. We reprocessed 357 astronegatives taken with the 26-inch refractor and the normal astrograph of the Pulkovo Observatory between 1972 and 2007 to obtain the positions of the main Saturnian moons in the second Gaia data release (Gaia DR2) system. Photographic plates were digitized with the Pulkovo Mobile Digitizing Device (MDD) scanner. The New Astrometric Reduction of Old Observations (NAROO) digitizer at the Paris Observatory was used to calibrate the scanned images. Satellite image centering and astrometric reduction were performed. In total, 6487 positions (equatorial coordinates) have been determined with an accuracy of 50mas. This is confirmed by a comparison of our data with modern ephemerides. The verification of the results was performed using data from past close approaches by Saturnian satellites to Gaia reference stars, showing the adequacy of the current residual analysis. A joint review of the Pulkovo and the United States Naval Observatory (USNO) intersatellite positions allows us to conclude about the existence of faint systematic effects in the satellite theories of motions at the 10mas level.