The Kepler Target Search interface provides access to a 12.5 million row table created by MAST by joining entries from the Kepler Input catalog (KIC) with the Kepler Characteristics table (CT) and merging these with "associated" entries from the United Kingdom Infrared Telescope (IRT) project, the USNOb catalog, GALEX, the Kepler Isaac Newton Telescope Survey (KIS), and the Everett KPNO (UBV) survey. The search interface allows users to find targets within the Kepler field of view (FOV) and allows searches on magnitudes, colors, and other parameters for both KIC and associated non-KIC targets.
This is the recommended interface for potential guest observers to locate possible targets for observation. GO proposers however should check on the target's position by either (or both) looking to one of our posted FFI images and seeing if it is on a chip, and (2) confirming this with the GO office.
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).
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.
The kinematics of 122 red giant and 124 RR Lyrae stars in the solar neighborhood are studied using accurate measurements of their proper motions obtained by the Hipparcos astrometry satellite, combined with their published photometric distances, metal abundances, and radial velocities. A majority of these sample stars have metal abundances of [Fe/H]<=-1 and thus represent the old stellar populations in the Galaxy. The halo component, with [Fe/H]<=-1.6, is characterized by a lack of systemic rotation [(<U>, <V>, <W>)=(16+/-18, -217+/-21, -10+/-12)km/s] and a radially elongated velocity ellipsoid [(<U>, <V>, <W>)=(161+/-10, 115+/-7, 108+/-7)km/s]. About 16% of such metal-poor stars have low orbital eccentricities (e<0.4), and we see no evidence of a correlation between [Fe/H] and e. Based on the model for the e-distribution of orbits, we show that this fraction of low-e stars for [Fe/H]<=-1.6 is explained by the halo component alone, without introducing the extra disk component claimed by recent workers. This is also supported by the absence of a significant change in the e-distribution with height from the Galactic plane. In the intermediate-metallicity range (-1.6<[Fe/H]<=-1), we find that stars with disklike kinematics have only modest effects on the distributions of rotational velocities and e for the sample at |z|<1kpc. This disk component appears to constitute only 10% for -1.6<[Fe/H]<=-1 and 20% for -1.4<[Fe/H]<=-1. It is also verified that this metal-weak disk has a mean rotation of ~195km/s and a vertical extent of 1 kpc, which is consistent with the thick disk's dominating at [Fe/H]=-0.6 to -1. We find no metallicity gradient in the halo, whereas there is an indication of a metallicity gradient in the metal-weak tail of the thick disk. The implications of these results for the early evolution of the Galaxy are also presented.
Radial velocities and proper motions (derived from the GSC-II data base) are given for 38 RR Lyrae (RRL) stars and 79 blue horizontal branch (BHB) stars in a ~200deg^2^ area around the North Galactic Pole (NGP). Both heliocentric (UVW) and galactocentric (VR, Vphi, Vz) space motions are derived for these stars using a homogeneous distance scale consistent with (m-M)0=18.52 for the Large Magellanic Cloud (LMC).
A list of known Galactic field stars exhibiting Blazhko effect containing 242 stars is presented. All the entries including their designations, positions, pulsation, and Blazhko periods were collected from the available literature. The actual values of parameters are given.
We present a catalog of 1143 periodic variables, compiled from our image-subtracted photometric analysis of the K2 Campaign-0 super stamp. This super stamp is centered on the open clusters M35 and NGC2158. Approximately 46% of our periodic variables were previously unreported. Of the catalog variables, we find that 331 are members of M35 and 56 are members of NGC 2158 (P_m_>0.5). Our catalog contains two new transiting exoplanet candidates, both of which orbit field stars. The smaller planet candidate has a radius of 0.35+/-0.04R_J_ and orbits a K dwarf (Kp=15.4mag) with a transit depth of 2.9mmag. The larger planet candidate has a radius of 0.72+/-0.02R_J_ and orbits a late G-type star (Kp=15.7mag) with a transit depth of 2.2mmag. The larger planet candidate may be an unresolved binary or a false alarm. Our catalog includes 44 eclipsing binaries (EBs), including ten new detections. Of the EBs, one is an M35 member and five are NGC 2158 members. Our catalog contains a total of 1097 nontransiting variable stars, including a field {delta} Cepheid exhibiting double mode pulsations, 561 rotational variables, and 251 pulsating variables (primarily {gamma} Doradus and {delta} Scuti types). The periods of our catalog sources range between 43 minutes to 24 days. The known ages of our reported cluster variables will facilitate investigations of a variety of stellar evolutionary processes.
We present K_s_-band light curves for 299 Cepheids in the Small Magellanic Cloud (SMC) of which 288 are new discoveries that we have identified using multi-epoch near-infrared photometry obtained by the VISTA survey of the Magellanic Clouds system (VMC). The new Cepheids have periods in the range from 0.34 to 9.1d and cover the magnitude interval 12.9<=<K_s_><=17.6mag. Our method was developed using variable stars previously identified by the optical microlensing survey OGLE. We focus on searching new Cepheids in external regions of the SMC for which complete VMC K_s_-band observations are available and no comprehensive identification of different types of variable stars from other surveys exists yet.
RR Lyrae variable stars are the primary Population II distance indicator. Likewise, the LMC constitutes a key step in the extragalactic distance scale. By combining near-IR photometry and spectroscopically measured metallicities for a homogeneous sample of 50 RR Lyr stars in the Large Magellanic Cloud (LMC), we investigate the metallicity dependence of the period-luminosity relation in the near-infrared (IR), use the newly derived relations to re-derive the distance to the LMC, and compare the distance moduli obtained from RR Lyr and red clump stars.
K2 ugri & H{alpha} photometry in the Lagoon Nebula
Short Name:
J/AJ/162/101
Date:
14 Mar 2022 06:42:13
Publisher:
CDS
Description:
Space observatories have provided unprecedented depictions of the many variability behaviors typical of low-mass, young stars. However, those studies have so far largely omitted more massive objects (~2M{sun} to 4-5M{sun}) and were limited by the absence of simultaneous, multiwavelength information. We present a new study of young star variability in the ~1-2Myr old, massive Lagoon Nebula region. Our sample encompasses 278 young, late B to K-type stars, monitored with Kepler/K2. Auxiliary u, g, r, i, H{alpha} time-series photometry, simultaneous with K2, was acquired at the Paranal Observatory. We employed this comprehensive data set and archival infrared photometry to determine individual stellar parameters, assess the presence of circumstellar disks, and tie the variability behaviors to inner disk dynamics. We found significant mass-dependent trends in variability properties, with B/A stars displaying substantially reduced levels of variability compared to G/K stars for any light-curve morphology. These properties suggest different magnetic field structures at the surface of early-type and later-type stars. We also detected a dearth of some disk-driven variability behaviors, particularly dippers, among stars earlier than G. This indicates that their higher surface temperatures and more chaotic magnetic fields prevent the formation and survival of inner disk dust structures corotating with the star. Finally, we examined the characteristic variability timescales within each light curve and determined that the day-to-week timescales are predominant over the K2 time series. These reflect distinct processes and locations in the inner disk environment, from intense accretion triggered by instabilities in the innermost disk regions to variable accretion efficiency in the outer magnetosphere.
