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- ID:
- ivo://CDS.VizieR/J/ApJ/540/1016
- Title:
- K-band & NICMOS photometry of Trapezium Cluster
- Short Name:
- J/ApJ/540/1016
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained images of the Trapezium Cluster (140"x140"; 0.3pc x 0.3pc) with the Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). Combining these data with new ground-based K-band spectra (R=800) and existing spectral types and photometry, we have constructed an H-R diagram and used it and other arguments to infer masses and ages.
- ID:
- ivo://CDS.VizieR/J/MNRAS/452/3561
- Title:
- Kepler eclipsing binary stars. K2 Campaign 0
- Short Name:
- J/MNRAS/452/3561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The original Kepler mission observed and characterized over 2400 eclipsing binaries (EBs) in addition to its prolific exoplanet detections. Despite the mechanical malfunction and subsequent non-recovery of two reaction wheels used to stabilize the instrument, the Kepler satellite continues collecting data in its repurposed K2 mission surveying a series of fields along the ecliptic plane. Here, we present an analysis of the first full baseline K2 data release: the Campaign 0 data set. In the 7761 light curves we have identified a total of 207 EBs. Of these, 97 are new discoveries that were not previously identified. Our pixel-level analysis of these objects has also resulted in identification of several false positives (observed targets contaminated by neighbouring EBs), as well as the serendipitous discovery of two short-period exoplanet candidates. We provide catalogue cross-matched source identifications, orbital periods, morphologies and ephemerides for these eclipsing systems. We also describe the incorporation of the K2 sample into the Kepler Eclipsing Binary Catalog, present spectroscopic follow-up observations for a limited selection of nine systems and discuss prospects for upcoming K2 campaigns.
- ID:
- ivo://CDS.VizieR/J/AJ/142/160
- Title:
- Kepler Mission. II. Eclipsing binaries in DR2
- Short Name:
- J/AJ/142/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler Mission (launched in 2009 March) provides nearly continuous monitoring of ~156000 objects with unprecedented photometric precision. Coincident with the first data release, we presented a catalog of 1879 eclipsing binary systems identified within the 115deg^2^ Kepler field of view (FOV). Here, we provide an updated catalog from paper I (Prsa et al. 2011, Cat. J/AJ/141/83) augmented with the second Kepler data release which increases the baseline nearly fourfold to 125 days. Three hundred and eighty-six new systems have been added, ephemerides and principal parameters have been recomputed. We have removed 42 previously cataloged systems that are now clearly recognized as short-period pulsating variables and another 58 blended systems where we have determined that the Kepler target object is not itself the eclipsing binary. A number of interesting objects are identified. We present several exemplary cases: four eclipsing binaries that exhibit extra (tertiary) eclipse events; and eight systems that show clear eclipse timing variations indicative of the presence of additional bodies bound in the system. We have updated the period and galactic latitude distribution diagrams. With these changes, the total number of identified eclipsing binary systems in the Kepler FOV has increased to 2165, 1.4% of the Kepler target stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/728/117
- Title:
- Kepler planetary candidates. I.
- Short Name:
- J/ApJ/728/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the spring of 2009, the Kepler Mission commenced high-precision photometry on nearly 156000 stars to determine the frequency and characteristics of small exoplanets, conduct a guest observer program, and obtain asteroseismic data on a wide variety of stars. On 2010 June 15, the Kepler Mission released most of the data from the first quarter of observations. At the time of this data release, 705 stars from this first data set have exoplanet candidates with sizes from as small as that of Earth to larger than that of Jupiter. Here we give the identity and characteristics of 305 released stars with planetary candidates. Data for the remaining 400 stars with planetary candidates will be released in 2011 February. More than half the candidates on the released list have radii less than half that of Jupiter. Five candidates are present in and near the habitable zone; two near super-Earth size, and three bracketing the size of Jupiter. The released stars also include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth radius) candidates with near-resonant periods.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/174
- Title:
- Kepler rapid rotators and Ks-band excesses
- Short Name:
- J/ApJ/871/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tens of thousands of rotation periods have been measured in the Kepler fields, including a substantial fraction of rapid rotators. We use Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower main sequence, and compare their distribution of rotation properties to those of single stars both with and without Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectroscopic characterization. We find that 59% of stars with 1.5day<P<7day lie 0.3mag above the main sequence, compared with 28% of the full rotation sample. The fraction of stars in the same period range is 1.7{+/-}0.1% of the total sample analyzed for rotation periods. Both the PB fraction and the fraction of rapid rotators are consistent with a population of non-eclipsing short-period binaries inferred from Kepler eclipsing binary data after correcting for inclination. This suggests that the rapid rotators are dominated by tidally synchronized binaries rather than single stars obeying traditional angular momentum evolution. We caution against interpreting rapid rotation in the Kepler field as a signature of youth. Following up on this new sample of 217 candidate tidally synchronized binaries will help further understand tidal processes in stars.
- ID:
- ivo://CDS.VizieR/J/AJ/112/171
- Title:
- K Giants in Baade's Window. II
- Short Name:
- J/AJ/112/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second in a series of papers in which we analyze spectra of over 400 K and M giants in Baade's Window, including most of the stars with proper motions measured by Spaenhauer et al. (1992AJ....103..297S). In our first paper, we measured line-strength indices of Fe, Mg, CN, and HBeta and calibrated them on the system of Faber et al. (1985ApJS...57..711F). Here, we use the <Fe> index to derive an abundance distribution of [Fe/H] for 322 stars with effective temperatures between 3900K and 5160K. Our derived values of [Fe/H] agree well with those measured from high-resolution echelle spectra (e.g., McWilliam & Rich, 1994ApJS...91..749M) for the small number of stars in common. We find a mean abundance <[Fe/H]>=-0.11+/-0.04 for our sample of Baade's Window K giants. More than half the sample lie in the range -0.4<[Fe/H]<+0.3. We estimate line-of-sight distances for individual stars in our sample and confirm that, in Baade's Window, most K giants with V<15.5 are foreground disk stars, but the great majority (more than 80%) with V>16 belong to the bulge. We also compare the metallicities derived from the CN and Mg2 indices to those from iron. Most of the metal-rich stars in our sample appear to be CN-weak, in contrast to the situation in metal-rich globular clusters and elliptical galaxies. The metal-poor half of our sample ([Fe/H]<0) shows evidence for a mild Mg overenhancement ([Mg/Fe]~+0.2); but this is not seen in the more metal-rich stars ([Fe/H]>=0). The K giants in Baade's Window therefore share some, but not all, of the characteristics of stars in elliptical galaxies as inferred from their integrated light.
- ID:
- ivo://CDS.VizieR/J/A+A/610/A21
- Title:
- KiDS Survey for solar system objects mining
- Short Name:
- J/A+A/610/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The search for minor bodies in the Solar System promises insights into its formation history. Wide imaging surveys offer the opportunity to serendipitously discover and identify these traces of planetary formation and evolution. We present a method to acquire position, photometry, and proper motion measurements of Solar System objects in surveys using dithered image sequences. The application of this method on the Kilo-Degree Survey is demonstrated. Optical images of 346deg^2^ fields of the sky are searched in up to four filters using the AstrOmatic software suite to reduce the pixel to catalog data. The Solar System objects within the acquired sources are selected based on a set of criteria depending on their number of observation, motion, and size. The Virtual Observatory SkyBoT tool is used to identify known objects. We observed 20,221 SSO candidates, with an estimated false-positive content of less than 0.05%. Of these SSO candidates, 53.4% are identified by SkyBoT. KiDS can detect previously unknown SSOs because of its depth and coverage at high ecliptic latitude, including parts of the Southern Hemisphere. Thus we expect the large fraction of the 46.6% of unidentified objects to be truly new SSOs. Our method is applicable to a variety of dithered surveys such as DES, LSST, and Euclid. It offers a quick and easy-to-implement search for Solar System objects. SkyBoT can then be used to estimate the completeness of the recovered sample.
- ID:
- ivo://CDS.VizieR/J/MNRAS/317/460
- Title:
- Kinematics of Mira stars
- Short Name:
- J/MNRAS/317/460
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The space motions of Mira variables are derived from radial velocities, Hipparcos (<I/239>) proper motions and a period-luminosity relation. The previously known dependence of Mira kinematics on the period of pulsation is confirmed and refined. In addition, it is found that Miras with periods in the range 145-200d in the general Solar neighbourhood have a net radial outward motion from the Galactic Centre of 75+/-18km/s. This, together with a lag behind the circular velocity of Galactic rotation of 98+/-19km/s, is interpreted as evidence for an elongation of their orbits, with their major axes aligned at an angle of ~17{deg} with the Sun-Galactic Centre line, towards positive Galactic longitudes. This concentration seems to be a continuation to the Solar circle and beyond of the bar-like structure of the Galactic bulge, with the orbits of some local Miras probably penetrating into the bulge. These conclusions are not sensitive to the distance scale adopted. A further analysis is given of the short-period (SP) red group of Miras discussed in companion papers in this series. In Appendix A the mean radial velocities and other data for 842 oxygen-rich Mira-like variables are tabulated. These velocities were derived from published optical and radio observations.
- ID:
- ivo://CDS.VizieR/J/PAZh/33/643
- Title:
- Kinematics of Sco-Cen OB Association
- Short Name:
- J/PAZh/33/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A fine structure related to the kinematic peculiarities of three components of the Scorpius-Centaurus association (LCC = Lower Centaurus-Crux, UCL = Upper Centaurus-Lupus, and US = Upper Scorpius) has been revealed in the UV-velocity distribution of Gould Belt stars. We have been able to identify the most likely members of these groups by applying the method of analyzing the two-dimensional probability density function of stellar UV velocities that we developed. A kinematic analysis of the identified structural components has shown that, in general, the center-of-mass motion of the LCC, UCL, and US groups follows the motion characteristic of the Gould Belt, notably its expansion. The entire Scorpius-Centaurus complex is shown to possess a proper expansion with an angular velocity parameter of 46+/-8km/s/kpc for the kinematic center with l_0_=-40{deg} and R_0_=110pc found. Based on this velocity, we have estimated the characteristic expansion time of the complex to be 21+/-4Myr. The proper rotation velocity of the Scorpius-Centaurus complex is lower in magnitude, is determined less reliably, and depends markedly on the data quality.
