- ID:
- ivo://CDS.VizieR/J/ApJ/808/187
- Title:
- Metallicities of KIC stars without planets
- Short Name:
- J/ApJ/808/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Host star metallicities have been used to infer observational constraints on planet formation throughout the history of the exoplanet field. The giant planet metallicity correlation has now been widely accepted, but questions remain as to whether the metallicity correlation extends to the small terrestrial-sized planets. Here, we report metallicities for a sample of 518 stars in the Kepler field that have no detected transiting planets and compare their metallicity distribution to a sample of stars that hosts small planets (Rp<1.7R_{Earth}_). Importantly, both samples have been analyzed in a homogeneous manner using the same set of tools (Stellar Parameters Classification tool). We find the average metallicity of the sample of stars without detected transiting planets to be [m/H]_SNTP,dwarf_=-0.02+/-0.02dex and the sample of stars hosting small planets to be [m/H]_STP_=-0.02+/-0.02dex. The average metallicities of the two samples are indistinguishable within the uncertainties, and the two-sample Kolmogorov-Smirnov test yields a p-value of 0.68 (0.41{sigma}), indicating a failure to reject the null hypothesis that the two samples are drawn from the same parent population. We conclude that the homogeneous analysis of the data presented here supports the hypothesis that stars hosting small planets have a metallicity similar to stars with no known transiting planets in the same area of the sky.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/RAA/15.1154
- Title:
- M-giant star candidates in LAMOST DR 1
- Short Name:
- J/other/RAA/15.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a discrimination procedure with the spectral index diagram of TiO_5_ and CaH_2_+CaH_3_ to separate M giants from M dwarfs. Using the M giant spectra identified from LAMOST DR1 with high signal-to-noise ratio, we have successfully assembled a set of M giant templates, which show more reliable spectral features. Combining with the M dwarf/subdwarf templates in Zhong et al. (2015AJ....150...42Z, Cat. J/AJ/150/42), we present an extended library of M-type templates which includes not only M dwarfs with a well-defined temperature and metallicity grid but also M giants with subtypes from M0 to M6. Then, the template-fitting algorithm is used to automatically identify and classify M giant stars from LAMOST DR1. The resulting catalog of M giant stars is cross-matched with 2MASS JHKs and WISE W1/W2 infrared photometry. In addition, we calculated the heliocentric radial velocity of all M giant stars by using the cross-correlation method with the template spectrum in a zero-velocity rest frame. Using the relationship between the absolute infrared magnitude MJ and our classified spectroscopic subtype, we derived the spectroscopic distance of M giants with uncertainties of about 40%. A catalog of 8639 M giants is provided. As an additional result of this analysis, we also present a catalog of 101690 M dwarfs/subdwarfs which are processed by our classification pipeline.
- ID:
- ivo://CDS.VizieR/J/AJ/158/75
- Title:
- Mid-type M dwarfs planet occurrence rates
- Short Name:
- J/AJ/158/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies of planet occurrence rates largely relied on photometric stellar characterizations. In this paper, we present planet occurrence rates for mid-type M dwarfs using spectroscopy, parallaxes, and photometry to determine stellar characteristics. Our spectroscopic observations have allowed us to constrain spectral type, temperatures, and, in some cases, metallicities for 337 out of 561 probable mid-type M dwarfs in the primary Kepler field. We use a random forest classifier to assign a spectral type to the remaining 224 stars. Combining our data with Gaia parallaxes, we compute precise (~3%) stellar radii and masses, which we use to update planet parameters and occurrence rates for Kepler mid-type M dwarfs. Within the Kepler field, there are seven M3 V to M5 V stars that host 13 confirmed planets between 0.5 and 2.5 Earth radii and at orbital periods between 0.5 and 10 days. For this population, we compute a planet occurrence rate of 1.19_-0.49_^+0.70^ planets per star. For M3 V, M4 V, and M5 V, we compute planet occurrence rates of 0.86_-0.68_^+1.32^, 1.36_-1.02_^+2.30^, and 3.07_-2.49_^+5.49^ planets per star, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/77
- Title:
- Milky Way L/T/M-dwarfs identified in BoRG survey
- Short Name:
- J/ApJ/788/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a tally of Milky Way late-type dwarf stars in 68 Wide Field Camera 3 (WFC3) pure-parallel fields (227 arcmin^2^) from the Brightest of Reionizing Galaxies survey for high-redshift galaxies. Using spectroscopically identified M-dwarfs in two public surveys, the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey and the Early Release Science mosaics, we identify a morphological selection criterion using the half-light radius (r_50_), a near-infrared J-H, G-J color region where M-dwarfs are found, and a V-J relation with M-dwarf subtype. We apply this morphological selection of stellar objects, color-color selection of M-dwarfs, and optical-near-infrared color subtyping to compile a catalog of 274 M-dwarfs belonging to the disk of the Milky Way with a limiting magnitude of m_F125W_<24(AB). Based on the M-dwarf statistics, we conclude that (1) the previously identified north-south discrepancy in M-dwarf numbers persists in our sample; there are more M-dwarfs in the northern fields on average than in southern ones, (2) the Milky Way's single disk scale-height for M-dwarfs is 0.3-4 kpc, depending on subtype, (3) the scale-height depends on M-dwarf subtype with early types (M0-4) high scale-height (z_0_=3-4 kpc) and later types M5 and above in the thin disk (z_0_=0.3-0.5 kpc), (4) a second component is visible in the vertical distribution, with a different, much higher scale-height in the southern fields compared to the northern ones. We report the M-dwarf component of the Sagittarius stream in one of our fields with 11 confirmed M-dwarfs, seven of which are at the stream's distance. In addition to the M-dwarf catalog, we report the discovery of 1 T-dwarfs and 30 L-dwarfs from their near-infrared colors. The dwarf scale-height and the relative low incidence in our fields of L- and T-dwarfs in these fields makes it unlikely that these stars will be interlopers in great numbers in color-selected samples of high-redshift galaxies. The relative ubiquity of M-dwarfs however will make them ideal tracers of Galactic halo substructure with EUCLID and reference stars for James Webb Space Telescope observations.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1049
- Title:
- Millimetric and sub-mm obs. of solar-type stars
- Short Name:
- J/AJ/129/1049
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present submillimeter (Caltech Submillimeter Observatory 350{mu}m) and millimeter (Swedish-ESO Submillimetre Telescope [SEST] 1.2mm, Owens Valley Radio Observatory [OVRO] 3mm) photometry for 127 solar-type stars from the Formation and Evolution of Planetary Systems Spitzer Legacy program (FEPS, Meyer et al. 2004ApJS..154..422M) that have masses between ~0.5 and 2.0M_Sun_ and ages from ~3Myr to 3Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJ/705/1364
- Title:
- MIR catalog of point sources in M33
- Short Name:
- J/ApJ/705/1364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The progenitors of SN 2008S and the 2008 luminous transient in NGC 300 were deeply dust-enshrouded massive stars, with extremely red mid-infrared (MIR) colors and relatively low bolometric luminosities (~5x10^4^L_{sun}_). Because of the implied frequency of events similar to SN 2008S and NGC 300 and the interesting character of their progenitors, we searched for analogous sources in archival Spitzer imaging of nearby galaxies. Our goal was to identify the underlying subpopulation of massive stars from which these progenitors emerge, to characterize their properties and frequency, and to catalog them for future study. The Triangulum galaxy M33 is a perfect test case. It has an absolute B-band magnitude of M_B_~-19.2, a distance of ~0.96Mpc, and it has extensive optical, H{alpha}, MIR and FIR imaging.
- ID:
- ivo://CDS.VizieR/J/AJ/157/231
- Title:
- MLSDSS-GaiaDR2 sample of M and L dwarfs
- Short Name:
- J/AJ/157/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 74216 M and L dwarfs constructed from two existing catalogs of cool dwarfs spectroscopically identified in the Sloan Digital Sky Survey (SDSS). We cross-matched the SDSS catalog with Gaia DR2 (Cat. I/345) to obtain parallaxes and proper motions and modified the quality cuts suggested by the Gaia Collaboration to make them suitable for late-M and L dwarfs. We also provide relations between Gaia colors and absolute magnitudes with spectral type and conclude that (G-G_RP_) has the tightest relation to spectral type for M and L dwarfs. In addition, we study magnetic activity as a function of position on the color-magnitude diagram, finding that H{alpha} magnetically active stars have, on average, redder colors and/or brighter magnitudes than inactive stars. This effect cannot be explained by youth alone and might indicate that active stars are magnetically inflated, binaries, and/or high metallicity. Moreover, we find that vertical velocity and vertical action dispersion are correlated with H{alpha} emission, confirming that these two parameters are age indicators. We also find that stars below the main sequence have high tangential velocity, which is consistent with a low metallicity and old population of stars that belong to the halo or thick disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/158
- Title:
- M,L,T dwarfs fundamental parameters and SEDs
- Short Name:
- J/ApJ/810/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine optical, near-infrared, and mid-infrared spectra and photometry to construct expanded spectral energy distributions for 145 field age (>500 Myr) and 53 young (lower age estimate <500 Myr) ultracool dwarfs (M6-T9). This range of spectral types includes very low mass stars, brown dwarfs, and planetary mass objects, providing fundamental parameters across both the hydrogen and deuterium burning minimum masses for the largest sample assembled to date. A subsample of 29 objects have well constrained ages as probable members of a nearby young moving group. We use 182 parallaxes and 16 kinematic distances to determine precise bolometric luminosities (L_bol_) and radius estimates from evolutionary models give semi-empirical effective temperatures (T_eff_) for the full range of young and field age late-M, L, and T dwarfs. We construct age-sensitive relationships of luminosity, temperature, and absolute magnitude as functions of spectral type and absolute magnitude to disentangle the effects of degenerate physical parameters such as T_eff_, surface gravity, and clouds on spectral morphology. We report bolometric corrections in J for both field age and young objects and find differences of up to a magnitude for late-L dwarfs. Our correction in Ks shows a larger dispersion but not necessarily a different relationship for young and field age sequences. We also characterize the NIR-MIR reddening of low gravity L dwarfs and identify a systematically cooler T_eff_ of up to 300 K from field age objects of the same spectral type and 400 K cooler from field age objects of the same M_H_ magnitude.
- ID:
- ivo://CDS.VizieR/J/AJ/151/41
- Title:
- Motion Verified Red Stars (MoVeRS)
- Short Name:
- J/AJ/151/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric catalog of 8,735,004 proper motion selected low-mass stars (KML-spectral types) within the Sloan Digital Sky Survey (SDSS) footprint, from the combined SDSS-DR10, Two-Micron All-Sky Survey (2MASS) Point Source Catalog (PSC), and Wide-field Infrared Survey Explorer (WISE) AllWISE catalog. Stars were selected using r-i, i-z, r-z, z-J, and z-W1 colors, and SDSS, WISE, and 2MASS astrometry was combined to compute proper motions. The resulting 3,518,150 stars were augmented with proper motions for 5,216,854 earlier type stars from the combined SDSS and United States Naval Observatory B1.0 catalog (USNO-B). We used SDSS+USNO-B proper motions to determine the best criteria for selecting a clean sample of stars. Only stars whose proper motions were greater than their 2-sigma uncertainty were included. Our Motion Verified Red Stars (MoVeRS) catalog is available through SDSS CasJobs and VizieR.
- ID:
- ivo://CDS.VizieR/J/A+A/483/903
- Title:
- Mount Wilson index for main sequence F-K stars
- Short Name:
- J/A+A/483/903
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The largest dataset of stellar activity measurements available at present is the one obtained at the Mount Wilson Observatory, where high-precision CaII H+K fluxes have been measured from 1966 for about 2200 stars. Since the MgII H and K lines at {lambda}2800{AA} are formed in a similar way to the CaII H+K emission lines, they are also good indicators of chromospheric structure. The International Ultraviolet Explorer (IUE) provides a large database of UV spectra in the band 1150-3350{AA} from 1978 to 1995, which can also be used to study stellar activity. The main purpose of this study is to use the IUE spectra in the analysis of magnetic activity of main sequence F-K stars. Combining IUE observations of MgII and optical spectroscopy of CaII, the registry of activity of stars can be extended in time.
