- ID:
- ivo://CDS.VizieR/J/AJ/161/160
- Title:
- BINOCS: NEWFIRM & IRAC IR photometry of clusters
- Short Name:
- J/AJ/161/160
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We introduce a new binary detection technique, Binary INformation from Open Clusters using SEDs (binocs), which we show is able to determine reliable stellar multiplicity and masses over a much larger mass range than current approaches. This new technique determines accurate component masses of binary and single systems of the open clusters' main sequence by comparing observed magnitudes from multiple photometric filters to synthetic star spectral energy distributions (SEDs), allowing us to systematically probe the binary population for low-mass stars in clusters for eight well-studied open clusters. We provide new deep, infrared photometric catalogs (1.2-8.0 {mu}m) for the key open clusters NGC 1960 (M36), NGC 2099 (M37), NGC 2420, and NGC 2682 (M67), using observations from NOAO/NEWFIRM and Spitzer/IRAC. Using these deep multiwavelength catalogs, the binocs method is applied to these clusters to determine accurate component masses for unresolved cluster binaries. We explore binary fractions as a function of cluster age, Galactic location, and metallicity.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4173
- Title:
- Bright white dwarfs for high-speed photometry
- Short Name:
- J/MNRAS/472/4173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for asteroseismological studies and the search for transits from planetary debris. We have compiled an all-sky catalogue of ultraviolet, optical and infrared photometry as well as proper motions, which we propose as an essential tool for the preliminary identification and characterization of potential targets. We present data for 1864 known white dwarfs and 305 high-probability white dwarf candidates brighter than 17mag. We describe the spectroscopic follow-up of 135 stars, of which 82 are white dwarfs and 25 are hot subdwarfs. The new confirmed stars include six pulsating white dwarf candidates (ZZ Cetis), and nine white dwarf binaries with a cool main- sequence companion. We identify one star with a spectroscopic distance of only 25pc from the Sun. Around the time TESS is launched, we foresee that all white dwarfs in this sample will have trigonometric parallaxes measured by the ESA Gaia mission next year.
- ID:
- ivo://CDS.VizieR/J/A+A/356/141
- Title:
- BV photometry for components of HIP doubles
- Short Name:
- J/A+A/356/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using observations obtained with the Tycho instrument of the ESA Hipparcos satellite, a two-colour photometry is produced for components of more than 7000 Hipparcos double and multiple stars with angular separations 0.1 to 2.5 arcsec. We publish 9473 components of 5173 systems with separations above 0.3 arcsec. The majority of them did not have Tycho photometry in the Hipparcos catalogue. The magnitudes are derived in the Tycho B_T and V_T passbands, similar to the Johnson passbands. Photometrically resolved components of the binaries with statistically significant trigonometric parallaxes can be put on an HR diagram, the majority of them for the first time.
- ID:
- ivo://CDS.VizieR/J/A+A/419/167
- Title:
- BVRI photometry in metal-poor binaries
- Short Name:
- J/A+A/419/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explored the regions within a radius of 25 arcsec around 473 nearby, low-metallicity G- to M-type stars using (VR)I optical filters and small-aperture telescopes. About 10% of the sample was searched up to angular separations of 90 arcsec. We applied photometric and astrometric techniques to detect true physical companions to the targets. The great majority of the sample stars was drawn from the Carney-Latham surveys; their metallicities range from roughly solar to [Fe/H]=-3.5dex. Our I-band photometric survey detected objects that are between 0 and 5mag fainter (completeness) than the target stars; the maximum dynamical range of our exploration is 9mag.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/108
- Title:
- Calibrator of exoplanet-host stars
- Short Name:
- J/MNRAS/414/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Phase-referenced interferometric astrometry offers the possibility to look for exoplanets around bright stars. Instruments like PRIMA (Phase-Referenced Imaging and Micro-arcsecond Astrometry) will measure the astrometric wobble of a candidate star due to an exoplanet relative to a close-by 'calibrator' star, located within the instrument's observing field (1-arcmin in the PRIMA case). Stars with already known exoplanets will constitute the first targets for this technique, as it will provide a way to further specify the characteristics of the known exoplanets, such as the inclinations. The main requirement is to have a calibrator in the vicinity of the star. We provide here a list of calibrators for all stars with known exoplanets obtained using data mining and Virtual Observatory techniques. This list is available online and revised regularly. The calibrators are found from catalogues available at Centre de Donnees astronomiques de Strasbourg (CDS) using the SearchCal software developed at Jean-Marie Mariotti Center (JMMC). In our test case, the calibrators are found within 1 arcmin angular distance for approximately 50 per cent of the stars tested, and often closer. They are all faint objects from the Two Micron All Sky Survey (2MASS) with K magnitudes between 13 and 15. A list of the most promising targets is also given.
- ID:
- ivo://CDS.VizieR/J/AJ/156/264
- Title:
- California-Kepler Survey. VII. Planet radius gap
- Short Name:
- J/AJ/156/264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of planet sizes encodes details of planet formation and evolution. We present the most precise planet size distribution to date based on Gaia parallaxes, Kepler photometry, and spectroscopic temperatures from the California-Kepler Survey. Previously, we measured stellar radii to 11% precision using high-resolution spectroscopy; by adding Gaia astrometry, the errors are now 3%. Planet radius measurements are, in turn, improved to 5% precision. With a catalog of ~1000 planets with precise properties, we probed in fine detail the gap in the planet size distribution that separates two classes of small planets, rocky super-Earths and gas-dominated sub-Neptunes. Our previous study and others suggested that the gap may be observationally under-resolved and inherently flat-bottomed, with a band of forbidden planet sizes. Analysis based on our new catalog refutes this; the gap is partially filled in. Two other important factors that sculpt the distribution are a planet's orbital distance and its host-star mass, both of which are related to a planet's X-ray/UV irradiation history. For lower-mass stars, the bimodal planet distribution shifts to smaller sizes, consistent with smaller stars producing smaller planet cores. Details of the size distribution including the extent of the "sub-Neptune desert" and the width and slope of the gap support the view that photoevaporation of low-density atmospheres is the dominant evolutionary determinant of the planet size distribution.
- ID:
- ivo://CDS.VizieR/J/ApJ/790/158
- Title:
- Candidate halo wide binaries
- Short Name:
- J/ApJ/790/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an improved catalog of halo wide binaries compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. (2000, J/A+A/356/529) and Chaname & Gould (2004ApJ...601..289C), but we have also included binaries from the lists of Ryan (1992AJ....104.1144R) and Zapatero-Osorio & Martin (2004, J/A+A/419/167). All binaries were carefully checked and their distances and systemic radial velocities are included when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries, we ended up with 211 probable halo binaries, 150 of which have radial velocities available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law f(a) ~ a.^-1^ (Oepik's relation) up to different limits. For the 50 most disk-like binaries, those that spend their entire lives within z = +/-500 pc, this limit is found to be 19,000 AU (0.09 pc), while for the 50 most halo-like binaries, those that spend on average only 18% of their lives within z = +/-500 pc, the limit is 63,000 AU (0.31 pc). In a companion paper, we employ this catalog to establish limits on the masses of the halo massive perturbers (massive compact halo objects).
- ID:
- ivo://CDS.VizieR/J/AJ/143/134
- Title:
- Candidate members of {beta} Pic / AB Dor groups
- Short Name:
- J/AJ/143/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present moderate resolution (R~3575) optical spectra of 19 known or suspected members of the AB Doradus and {beta} Pictoris Moving Groups, obtained with the DeVeny Spectrograph on the 72inch Perkins telescope at Lowell Observatory. For four of five recently proposed members, signatures of youth such as LiI 6708{AA} absorption and H{alpha} emission further strengthen the case for youth and membership. The lack of detected lithium in the proposed {beta} Pic member TYC 2211-1309-1 implies that it is older than all other K-type members and weakens the case for membership. Effective temperatures are determined via line ratio analyses for the 11 F, G, and early-K stars observed, and via spectral comparisons for the eight late-K and M stars observed. We assemble updated candidate membership lists for these moving groups that account for known binarity. Currently, the AB Dor Moving Group contains 127 proposed members and the {beta} Pic Moving Group holds 77 proposed members. We then use temperature, luminosity, and distance estimates to predict angular diameters for these stars; the motivation is to identify stars that can be spatially resolved with long-baseline optical/infrared interferometers in order to improve age estimates for these groups and to constrain evolutionary models at young ages. Considering the portion of the sky accessible to northern hemisphere facilities (DE>-30), six stars have diameters large enough to be spatially resolved ({theta}>0.4mas) with the CHARA Array, which currently has the world's longest baseline of 331m; this subsample includes the low-mass M2.5 member of AB Dor, GJ 393, which is likely to still be pre-main sequence. For southern hemisphere facilities (DE<+30), 18 stars have diameters larger than this limiting size, including the low-mass debris disk star AU Mic (0.72mas). However, the longest baselines of southern hemisphere interferometers (160m) are only able to resolve the largest of these, the B6 star {alpha} Gru (1.17mas); proposed long-baseline stations may alleviate the current limitations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/3133
- Title:
- Candidate Neptunes around late-type dwarfs
- Short Name:
- J/MNRAS/437/3133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of transiting Neptune-size planets orbiting close to nearby bright stars can inform theories of planet formation because mass and radius and therefore mean density can be accurately estimated and compared with interior models. The distribution of such planets with stellar mass and orbital period relative to their Jovian-mass counterparts can test scenarios of orbital migration, and whether "hot" (period <10d) Neptunes evolved from "hot" Jupiters as a result of mass loss. We searched 1763 late K and early M dwarf stars for transiting Neptunes by analyzing photometry from the Wide Angle Search for Planets and obtaining high-precision (<=10^-3^) follow-up photometry of stars with candidate transit signals. We identified 92 candidate signals among 80 other stars and carried out 148 observations of predicted candidate transits with 1-2m telescopes.
- ID:
- ivo://CDS.VizieR/J/ApJ/770/90
- Title:
- Candidate planets in the habitable zones
- Short Name:
- J/ApJ/770/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A key goal of the Kepler mission is the discovery of Earth-size transiting planets in "habitable zones" where stellar irradiance maintains a temperate climate on an Earth-like planet. Robust estimates of planet radius and irradiance require accurate stellar parameters, but most Kepler systems are faint, making spectroscopy difficult and prioritization of targets desirable. The parameters of 2035 host stars were estimated by Bayesian analysis and the probabilities p_HZ_ that 2738 candidate or confirmed planets orbit in the habitable zone were calculated. Dartmouth Stellar Evolution Program models were compared to photometry from the Kepler Input Catalog, priors for stellar mass, age, metallicity and distance, and planet transit duration. The analysis yielded probability density functions for calculating confidence intervals of planet radius and stellar irradiance, as well as p_HZ_. Sixty-two planets have p_HZ_>0.5 and a most probable stellar irradiance within habitable zone limits. Fourteen of these have radii less than twice the Earth; the objects most resembling Earth in terms of radius and irradiance are KOIs 2626.01 and 3010.01, which orbit late K/M-type dwarf stars. The fraction of Kepler dwarf stars with Earth-size planets in the habitable zone ({eta}_{Earth}_) is 0.46, with a 95% confidence interval of 0.31-0.64. Parallaxes from the Gaia mission will reduce uncertainties by more than a factor of five and permit definitive assignments of transiting planets to the habitable zones of Kepler stars.