- ID:
- ivo://CDS.VizieR/J/ApJS/237/38
- Title:
- Extended abundance analysis of KOIs
- Short Name:
- J/ApJS/237/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate stellar parameters and precise elemental abundances are vital pieces to correctly characterize discovered planetary systems, better understand planet formation, and trace galactic chemical evolution. We have performed a uniform spectroscopic analysis for 1127 stars, yielding accurate gravity, temperature, and projected rotational velocity in addition to precise abundances for 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, and Y). Most of the stars in this sample are Kepler Objects of Interest, observed by the California-Kepler Survey, and include 1003 stars hosting 1562 confirmed planets. This catalog extends the uniform analysis of our previous catalog, bringing the total number of homogeneously analyzed stars to almost 2700 F, G, and K dwarfs. To ensure consistency between the catalogs, we performed an analysis of our ability to recover parameters as a function of signal-to-noise ratio (S/N) and present individual uncertainties as well as functions to calculate uncertainties for parameters derived from lower S/N spectra. With the updated parameters, we used isochrone fitting to derive new radii, masses, and ages for the stars. We use our abundance analysis to support the finding that the radius gap is likely a result of evolution rather than the result of primordial compositional differences between the two populations.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/498/5720
- Title:
- Extended Breakthrough Listen sample
- Short Name:
- J/MNRAS/498/5720
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend the source sample recently observed by the Breakthrough Listen Initiative by including additional stars (with parallaxes measured by Gaia) that also reside within the FWHM of the GBT and Parkes radio telescope target fields. These stars have estimated distances as listed in the extensions of the Gaia DR2 catalogue. Enlarging the sample from 1327 to 288315 stellar objects permits us to achieve substantially better Continuous Waveform Transmitter Rate Figures of Merit (CWTFM) than any previous analysis, and allows us to place the tightest limits yet on the prevalence of nearby high-duty-cycle extraterrestrial transmitters. The results suggest <~0.0660(+0.0004,-0.0003)% of stellar systems within 50 pc host such transmitters (assuming an EIRP>~10^13^W) and <~0.039(+0.004,-0.008)% within 200pc (assuming an EIRP>~2.5*10^14^W). We further extend our analysis to much greater distances, though we caution that the detection of narrow-band signals beyond a few hundred pc may be affected by interstellar scintillation. The extended sample also permits us to place new constraints on the prevalence of extraterrestrial transmitters by stellar type and spectral class. Our results suggest targeted analyses of SETI radio data can benefit from taking into account the fact that in addition to the target at the field centre, many other cosmic objects reside within the primary beam response of a parabolic radio telescope. These include foreground and background galactic stars, but also extragalactic systems. With distances measured by Gaia, these additional sources can be used to place improved limits on the prevalence of extraterrestrial transmitters, and extend the analysis to a wide range of cosmic objects.
- ID:
- ivo://CDS.VizieR/V/137D
- Title:
- Extended Hipparcos Compilation (XHIP)
- Short Name:
- V/137D
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Extended Hipparcos Compilation (XHIP) cross-references the New Hipparcos Reduction (HIP2, Cat. I/311) with relatable data from a broad survey of presently available sources. The resulting collection uniquely assigns 116,096 spectral classifications, 46,392 radial velocities, and 19,097 iron abundances [Fe/H] to Hipparcos stars. Stellar classifications from SIMBAD and indications of multiplicity from either CCDM (Cat. I/274) or WDS (Cat. B/wds) are provided. Parameters for solar encounters and Galactic orbits are calculated for a subset of stars that can be made kinematically complete. Memberships in open clusters and stellar associations are assigned. We also provide stellar ages from The Geneva-Copenhagen survey of the Solar neighbourhood III (Cat. V/130), identifications of exoplanet host stars, and supplemental photometry from 2MASS (Cat. II/246) and SIMBAD.
- ID:
- ivo://CDS.VizieR/J/ApJ/678/96
- Title:
- Extragalactic H2O masers
- Short Name:
- J/ApJ/678/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Green Bank Telescope, we conducted a "snapshot" survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted of nearby (v<5000km/s) and luminous (M_B_<-19.5) galaxies, some with known nuclear activity but most not previously known to host AGNs. Our detections include both megamasers associated with AGNs and relatively low luminosity masers probably associated with star formation. The detection in UGC 3789 is particularly intriguing because the spectrum shows both systemic and high-velocity lines indicative of emission from an AGN accretion disk seen edge-on. Based on 6 months of monitoring, we detected accelerations among the systemic features ranging from 2 to 8km/s/yr, the larger values belonging to the most redshifted systemic components. High-velocity maser lines in UGC 3789 show no detectable drift over the same period. Although UGC 3789 was not known to be an AGN prior to this survey, the presence of a disk maser is strong evidence for nuclear activity, and an optical spectrum obtained later has confirmed it. With follow-up observations, it may be possible to measure a geometric distance to UGC 3789.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A113
- Title:
- Extrasolar planets. Radial velocities of eight stars
- Short Name:
- J/A+A/538/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass domain where massive extrasolar planets and brown dwarfs lie is still poorly understood. Indeed, not even a clear dividing line between massive planets and brown dwarfs has been established yet. This is partly because these objects are very scarce in close orbits around solar-type stars, the so-called brown dwarf desert. Owing to this, it has proven difficult to set up a strong observational base with which to compare models and theories of formation and evolution. We search to increase the current sample of massive sub-stellar objects with precise orbital parameters, and to constrain the true mass of detected sub-stellar candidates
- ID:
- ivo://CDS.VizieR/J/A+A/545/A55
- Title:
- Extrasolar planets. Radial velocities of 5 stars
- Short Name:
- J/A+A/545/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial-velocity measurements obtained in one of a number of programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Haute-Provence Observatory. Targets were selected from catalogs observed with ELODIE, which had been mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A46
- Title:
- Extrasolar planets. Radial velocities of 5 stars
- Short Name:
- J/A+A/585/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Long-period brown dwarf companions detected in radial velocity surveys are important targets for direct imaging and astrometry to calibrate the mass-luminosity relation of substellar objects. Through a 20-year radial velocity monitoring of solar-type stars that began with ELODIE and was extended with SOPHIE spectrographs, giant exoplanets and brown dwarfs with orbital periods longer than ten years are discovered. We report the detection of five new potential brown dwarfs with minimum masses between 32 and 83M_Jup_ orbiting solar-type stars with periods longer than ten years. An upper mass limit of these companions is provided using astrometric Hipparcos data, high-angular resolution imaging made with PUEO, and a deep analysis of the cross-correlation function of the main stellar spectra to search for blend effects or faint secondary components. These objects double the number of known brown dwarf companions with orbital periods longer than ten years and reinforce the conclusion that the occurrence of such objects increases with orbital separation. With a projected separation larger than 100mas, all these brown dwarf candidates are appropriate targets for high-contrast and high angular resolution imaging.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/1681
- Title:
- Extremely metal-poor stars CaII triplet
- Short Name:
- J/MNRAS/434/1681
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend our previous calibration of the infrared CaII triplet (CaT) as a metallicity indicator to the metal-poor regime by including observations of 55 field stars with [Fe/H] down to -4.0dex. While we previously solved the saturation at high metallicity using a combination of a Lorentzian and a Gaussian to reproduce the line profiles, in this paper we address the non-linearity at low metallicity following the suggestion of Starkenburg et al. of adding two non-linear terms to the relation among the [Fe/H], luminosity and strength of the calcium triplet lines. Our calibration thus extends from -4.0 to +0.5 in metallicity and is presented using four different luminosity indicators: V-V_HB_, M_V_, M_I_ and M_K_. The calibration obtained in this paper results in a tight correlation between [Fe/H] abundances measured from high-resolution spectra and [Fe/H] values derived from the CaT, over the whole metallicity range covered.
- ID:
- ivo://CDS.VizieR/J/A+A/501/519
- Title:
- Extremely metal-poor turnoff stars abundances
- Short Name:
- J/A+A/501/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detailed chemical abundances of extremely metal-poor (EMP) stars are key guides to understanding the early chemical evolution of the Galaxy. Most existing data, however, treat giant stars that may have experienced internal mixing later. We aim to compare the results for giants with new, accurate abundances for all observable elements in 18 EMP turnoff stars. VLT/UVES spectra at ~45000 and S/N ~130 per pixel (330-1000nm) are analysed with OSMARCS model atmospheres and the TURBOSPECTRUM code to derive abundances for C, Mg, Si, Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, and Ba. For Ca, Ni, Sr, and Ba, we find excellent consistency with our earlier sample of EMP giants, at all metallicities. However, our abundances of C, Sc, Ti, Cr, Mn and Co are ~0.2dex larger than in giants of similar metallicity. Mg and Si abundances are ~0.2dex lower (the giant [Mg/Fe] values are slightly revised), while Zn is again ~0.4dex higher than in giants of similar [Fe/H] (6 stars only). For C, the dwarf/giant discrepancy could possibly have an astrophysical cause, but for the other elements it must arise from shortcomings in the analysis. Approximate computations of granulation (3D) effects yield smaller corrections for giants than for dwarfs, but suggest that this is an unlikely explanation, except perhaps for C, Cr, and Mn. NLTE computations for Na and Al provide consistent abundances between dwarfs and giants, unlike the LTE results, and would be highly desirable for the other discrepant elements as well. Meanwhile, we recommend using the giant abundances as reference data for Galactic chemical evolution models.
- ID:
- ivo://CDS.VizieR/J/AJ/113/1026
- Title:
- Fabry-Perot Observations of M15
- Short Name:
- J/AJ/113/1026
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used an Imaging Fabry-Perot Spectrophotometer with the Sub-arcsecond Imaging Spectrograph on the Canada-France-Hawaii Telescope to measure velocities for 1534 stars in the globular cluster M15 (NGC 7078) with uncertainties between 0.5 and 10km/s. Combined with previous velocity samples, the total number of stars with measured velocities in M15 is 1597. An average seeing of 0.8" allowed us to obtain velocities for 144 stars within 10" of the center of M15, including 12 stars within 2". The velocity dispersion profile for M15 remains flat at a value of 11km/s from a radius of 0.4 into our innermost reliable point at 0.02 (0.06pc). Assuming an isotropic velocity dispersion tensor, this profile and the previously-published surface brightness profile can be equally well represented either by a stellar population whose M/L varies with radius from 1.7 in solar units at large radii to 3 in the central region, or by a population with a constant M/L of 1.7 and a central black hole of 1000M_{sun}_. A non-parametric mass model that assumes no black hole, no rotation, and isotropy constrains the mass density of M15 to better than 30% at a radius of 0.07 parsecs. The mass-density profile of this model is well represented by a power law with an exponent of -2.2, the value predicted by models of cluster core-collapse. Using the assumption of local thermodynamic equilibrium, we estimate the present-day mass function and infer a significant number of 0.6-0.7 M_{sun}_ objects in the central few parsecs, 85% of which may be in the form of stellar remnants. Not only do we detect rotation; we find that the position angle of the projected rotation axis in the central 10" is 100deg different from that of the whole sample. We also detect an increase in the amplitude of the rotation at small radii. Although this increase needs to be confirmed with better-seeing data, it may be the result of a central mass concentration. (Copyright) 1997 American Astronomical Society.
