- ID:
- ivo://CDS.VizieR/J/MNRAS/412/1210
- Title:
- Kepler asteroseismic targets
- Short Name:
- J/MNRAS/412/1210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar structure and evolution can be studied in great detail by asteroseismic methods, provided data of high precision are available. We determine the effective temperature (Teff), surface gravity (logg), metallicity, and the projected rotational velocity (vsini) of 44 Kepler asteroseismic targets using our high-resolution (R>20000) spectroscopic observations; these parameters will then be used to compute asteroseismic models of these stars and to interpret the Kepler light curves.We use the method of cross correlation to measure the radial velocity (RV) of our targets, while atmospheric parameters are derived using the ROTFIT code and spectral synthesis method.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/829/34
- Title:
- Kepler heartbeat star radial velocities
- Short Name:
- J/ApJ/829/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Heartbeat stars (HB stars) are a class of eccentric binary stars with close periastron passages. The characteristic photometric HB signal evident in their light curves is produced by a combination of tidal distortion, heating, and Doppler boosting near orbital periastron. Many HB stars continue to oscillate after periastron and along the entire orbit, indicative of the tidal excitation of oscillation modes within one or both stars. These systems are among the most eccentric binaries known, and they constitute astrophysical laboratories for the study of tidal effects. We have undertaken a radial velocity (RV) monitoring campaign of Kepler HB stars in order to measure their orbits. We present our first results here, including a sample of 22 Kepler HB systems, where for 19 of them we obtained the Keplerian orbit and for 3 other systems we did not detect a statistically significant RV variability. Results presented here are based on 218 spectra obtained with the Keck/HIRES spectrograph during the 2015 Kepler observing season, and they have allowed us to obtain the largest sample of HB stars with orbits measured using a single instrument, which roughly doubles the number of HB stars with an RV measured orbit. The 19 systems measured here have orbital periods from 7 to 90 days and eccentricities from 0.2 to 0.9. We show that HB stars draw the upper envelope of the eccentricity-period distribution. Therefore, HB stars likely represent a population of stars currently undergoing high eccentricity migration via tidal orbital circularization, and they will allow for new tests of high eccentricity migration theories.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A113
- Title:
- Kepler red giants in eclipsing binaries RVs
- Short Name:
- J/A+A/648/A113
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Eclipsing binaries (EBs) are unique targets for measuring accurate stellar properties and constraining stellar evolution models. In particular, it is possible to measure masses and radii at the few percent level for both components of a double-lined spectroscopic EB (SB2-EB). On the one hand, detached EBs hosting at least one star with detectable solar-like oscillations constitute ideal test objects to verify the ability of ensemble asteroseismology to derive stellar properties. On the other hand, the oscillations and surface activity of stars that belong to EBs offer unique information about the evolution of binary systems. This paper builds upon previous works dedicated to red giant stars (RG) in EBs; so far 20 known systems have been discovered by the NASA Kepler mission. We report the discovery of 16 RGs in EBs, which are also from the Kepler data, leading to a total of 36 confirmed RG stars in EBs from the original Kepler mission. This new sample includes three SB2-EBs with oscillations, resulting in a total of 14 known SB2-EBs with an oscillating RG component. This sample also includes six close systems in which the RG display a clear surface activity and complete oscillation suppression. Based on dedicated high-resolution spectroscopic observations (Apache Point Observatory, Observatoire de Haute Provence), we focus on three main aspects. Firstly, from the extended sample of 14 SB2-EBs, we confirm that the simple application of the asteroseismic scaling relations to RGs overestimates masses and radii of RGs by about 15% and 5 %. This bias can be reduced by employing either new asteroseismic reference values for RGs or model-based corrections of the asteroseismic parameters. Secondly, we confirm that close binarity leads to a high level of photometric modulation (up to 10%) and a suppression of solar-like oscillations. In particular, we show that it reduces the lifetime of radial modes by a factor of up to 10. Thirdly, we use our 16 new systems to complement previous observational studies that aimed to constrain tidal dissipation in interacting binaries. We confirm the important role of the equilibrium tide in binary evolution, but we also identify systems with circular orbits despite relatively young ages, which suggests the need to explore complementary tidal dissipation mechanisms in the future. Finally, as a by-product, we report the measurements of mass, radius, and age of three M-dwarf companion stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/97/835
- Title:
- K giants at the South Galactic Pole
- Short Name:
- J/A+AS/97/835
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/644/A1
- Title:
- 4 K giants velocity curves
- Short Name:
- J/A+A/644/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial-velocity (RV) measurements for the K giant stars HD 25723, 17 Sco, 3 Cnc and 44 UMa, taken at the Lick Observatory between 2000 and 2011. The best Keplerian fits to the data yield minimum masses of 2.5MJup and 4.3M_Jup_ for the planets orbiting HD 25723 and 17 Sco, respectively. The minimum masses of an additional candidate around HD 25723, and of planet candidates around 3 Cnc and 44 UMa, would be 1.3M_Jup_, 20.7M_Jup_ and 12.1M_Jup_, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/11
- Title:
- KIC 9777062 RVs & asteroseismology in NGC6811
- Short Name:
- J/ApJ/831/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of an eccentric, partially eclipsing long-period (P=19.23 days) binary system KIC 9777062 that contains main-sequence stars near the turnoff of the intermediate-age open cluster NGC 6811. The primary is a metal-lined Am star with a possible convective blueshift to its radial velocities, and one star (probably the secondary) is likely to be a {gamma} Dor pulsator. The component masses are 1.603+/-0.006(stat.)+/-0.016(sys.) and 1.419+/-0.003+/-0.008M_{sun}_, and the radii are 1.744+/-0.004+/-0.002 and 1.544+/-0.002+/-0.002R_{sun}_. The isochrone ages of the stars are mildly inconsistent: the age from the mass-radius combination for the primary (1.05+/-0.05+/-0.09Gyr, where the last quote was systematic uncertainty from models and metallicity) is smaller than that from the secondary (1.21+/-0.05+/-0.15Gyr) and is consistent with the inference from the color-magnitude diagram (1.00+/-0.05Gyr). We have improved the measurements of the asteroseismic parameters {Delta}{nu} and {nu}_max_ for helium-burning stars in the cluster. The masses of the stars appear to be larger (or alternately, the radii appear to be smaller) than predicted from isochrones using the ages derived from the eclipsing stars. The majority of stars near the cluster turnoff are pulsating stars: we identify a sample of 28 {delta} Sct, 15 {gamma} Dor, and 5 hybrid types. We used the period-luminosity relation for high-amplitude {delta} Sct stars to fit the ensemble of the strongest frequencies for the cluster members, finding (m-M)_V_=10.37+/-0.03. This is larger than most previous determinations, but smaller than values derived from the eclipsing binary (10.47+/-0.05).
- ID:
- ivo://CDS.VizieR/J/A+AS/122/521
- Title:
- Kinematical data on early-type galaxies. I.
- Short Name:
- J/A+AS/122/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of an ongoing program on the main parameters of early-type galaxies, we have performed long-slit absorption spectroscopy on a sample of 21 ellipticals and S0s. We present determinations of the central velocity dispersion and, for 18 objects, velocity-dispersion profiles and rotation curves.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/15
- Title:
- Kinematical data on early-type galaxies. II.
- Short Name:
- J/A+AS/126/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new kinematical data for a sample of 38 early-type galaxies. Rotation curves and velocity-dispersion profiles are determined for 32 objects, while the central velocity dispersions are given for the whole sample. This is our second paper in a series devoted to the presentation of kinematical data on elliptical and S0 galaxies, derived from long-slit absorption spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/519
- Title:
- Kinematical data on early-type galaxies. III.
- Short Name:
- J/A+AS/126/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new kinematical data for a sample of 24 early-type galaxies. Rotation curves and velocity-dispersion profiles are determined for 21 objects, while the central velocity dispersions are given for the whole sample. This is our third paper in a series devoted to the presentation of kinematical data on elliptical and S0 galaxies, derived from long-slit absorption spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/287
- Title:
- Kinematical data on early-type galaxies. IV.
- Short Name:
- J/A+AS/131/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present kinematical data for a sample of 25 galaxies. Rotation curves and velocity-dispersion profiles are determined for 16 objects, while the central velocity dispersions are given for the whole sample. This is our fourth paper in a series devoted to the presentation of kinematical data on elliptical and S0 galaxies, derived from long-slit absorption spectroscopy.