- ID:
- ivo://CDS.VizieR/J/ApJ/773/168
- Title:
- Submm fluxes of very low-mass stars and BDs
- Short Name:
- J/ApJ/773/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present SCUBA-2 850{mu}m observations of seven very low mass stars (VLMS) and brown dwarfs (BDs). Three are in Taurus and four in the TW Hydrae Association (TWA), and all are classical T Tauri (cTT) analogs. We detect two of the three Taurus disks (one only marginally), but none of the TWA ones. For standard grains in cTT disks, our 3{sigma} limits correspond to a dust mass of 1.2M_{Earth}_ in Taurus and a mere 0.2M_{Earth}_ in the TWA (3-10x deeper than previous work). We combine our data with other submillimeter/millimeter (sub-mm/mm) surveys of Taurus, {rho} Oph, and the TWA to investigate the trends in disk mass and grain growth during the cTT phase.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1089
- Title:
- SUNS and DEBRIS surveys target selection
- Short Name:
- J/MNRAS/403/1089
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Debris discs - analogous to the asteroid and Kuiper-Edgeworth belts in the Solar system - have so far mostly been identified and studied in thermal emission shortward of 100um. The Herschel space observatory and the Submillimetre Common-User Bolometer Array-2 (SCUBA-2) camera on the James Clerk Maxwell Telescope will allow efficient photometric surveying at 70 to 850um, which allows for the detection of cooler discs not yet discovered, and the measurement of disc masses and temperatures when combined with shorter wavelength photometry. The SCUBA-2 Unbiased Nearby Stars survey (SUNS) and the Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre (DEBRIS) Herschel Open Time Key Project are complementary legacy surveys observing samples of ~500 nearby stellar systems. To maximize the legacy value of these surveys, great care has gone into the target selection process. This paper describes the target selection process and presents the target lists of these two surveys.
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/1117
- Title:
- SuperWASP exoplanetary transit survey
- Short Name:
- J/MNRAS/372/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric transit surveys promise to complement the currently known sample of extra-solar planets (ESPs) by providing additional information on the planets and especially their radii. Here, we present ESP candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP North located in La Palma during the 2004 April to October observing season. The data cover fields between 23 and 03h in RA at declinations above +12{deg}. This amounts to over >>400000 stars with V magnitudes 8-13.5. For the stars brighter than 12.5, we achieve better than 1% photometric precision. Here, we present 41 sources with low-amplitude variability between >>1 and 10mmag, from which we select 12 with periods between 1.2 and 4.4d as the most promising ESP candidates. We discuss the properties of these ESP candidates, the expected fraction of transits recovered for our sample and implications for the frequency and detection of hot-Jupiters.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/158
- Title:
- Survey of Class II sources in Taurus with ALMA
- Short Name:
- J/ApJ/872/158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a survey of young single and multiple systems in the Taurus-Auriga star-forming region with the Atacama Large Millimeter Array (ALMA), substantially improving both the spatial resolution and sensitivity with which individual protoplanetary disks in these systems have been observed. These ALMA observations can resolve binary separations as small as 25-30au and have an average 3{sigma} detection level of 0.35mJy, equivalent to a disk mass of 4x10^-5^M_{sun}_ for an M3 star. Our sample was constructed from stars that have an infrared excess and/or signs of accretion and have been classified as Class II. For the binary and higher-order multiple systems observed, we detect {lambda}=1.3mm continuum emission from one or more stars in all of our target systems. Combined with previous surveys of Taurus, our 21 new detections increase the fraction of millimeter-detected disks to over 75% in all categories of stars (singles, primaries, and companions) earlier than spectral type M6 in the Class II sample. Given the wealth of other information available for these stars, this has allowed us to study the impact of multiplicity with a much larger sample. While millimeter flux and disk mass are related to stellar mass as seen in previous studies, we find that both primary and secondary stars in binary systems with separations of 30-4200au have lower values of millimeter flux as a function of stellar mass than single stars. We also find that for these systems, the circumstellar disk around the primary star does not dominate the total disk mass in the system and contains on average 62% of the total mass.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/141
- Title:
- T dwarf companions around M, L, T dwarfs in IR
- Short Name:
- J/ApJ/743/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observational techniques, results, and Monte Carlo population analyses from a Spitzer Infrared Array Camera imaging survey for substellar companions to 117 nearby M, L, and T dwarf systems (median distance of 10pc, mass range of 0.6 to ~0.05M_{sun}_). The two-epoch survey achieves typical detection sensitivities to substellar companions of [4.5um]<=17.2mag for angular separations between about 7" and 165". Based on common proper motion analysis, we find no evidence for new substellar companions. Using Monte Carlo orbital simulations (assuming random inclination, random eccentricity, and random longitude of pericenter), we conclude that the observational sensitivities translate to an ability to detect 600-1100K brown dwarf companions at semimajor axes >~35AU and to detect 500-600 K companions at semimajor axes >~60AU. The simulations also estimate a 600-1100K T dwarf companion fraction of <3.4% for 35-1200AU separations and <12.4% for the 500-600K companions for 60-1000AU separations.
- ID:
- ivo://CDS.VizieR/IV/39
- Title:
- TESS Input Catalog version 8.2 (TIC v8.2)
- Short Name:
- IV/39
- Date:
- 03 Mar 2022 07:19:26
- Publisher:
- CDS
- Description:
- We define various types of "phantom" stars that may appear in the TESS Input Catalog (TIC), and provide examples and lists of currently known cases. We present a methodology that can be used to check for phantoms around any object of interest in the TIC, and we present an approach for correcting the TIC-reported flux contamination factors accordingly. We checked all 2077 TESS Objects of Interest (TOIs) known as of July 21st 2020 (Sectors 1 to 24) and sent corrections for 291 stars to MAST where they are integrated into the publicly available TIC-8, updating it to TIC 8.1. We used the experience gained to construct an all-sky algorithm searching for "phantoms" which led to 34 million updates integrated into TIC 8.2.
- ID:
- ivo://CDS.VizieR/IV/38
- Title:
- TESS Input Catalog - v8.0 (TIC-8)
- Short Name:
- IV/38
- Date:
- 11 Feb 2022 14:26:27
- Publisher:
- CDS
- Description:
- The TIC is used to help identify two-minute cadence target selection for the Transiting Exoplanet Survey Satellite (TESS) mission, and to calculate physical and observational properties of planet candidates. It is for use by both the TESS science team and the public, and it is periodically updated - the current version is TIC-8. TIC-8 uses the GAIA DR2 catalog as a base and merges a large number of other photometric catalogs, including 2MASS, UCAC4, APASS, SDSS, WISE, etc. There are roughly 1.5 billion stellar and extended sources in TIC-8, containing compiled magnitudes including B, V, u, g, r, i, z, J, H, K, W1-W4, and G. This version was released in May 2019, and is expected to be the last official version of the TIC produced by the TESS mission, although future, independent development of the TIC is possible. The TIC is the responsibility of the SAO Arm of the TESS Science Office under the leadership of David Latham. The TESS Target Selection Working Group (TSWG) is co-chaired by Keivan Stassun (Vanderbilt) & Joshua Pepper (Lehigh).
- ID:
- ivo://CDS.VizieR/J/AJ/157/113
- Title:
- TESS M-dwarf exoplanetary systems
- Short Name:
- J/AJ/157/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the M-dwarf exoplanetary systems forthcoming from NASA's TESS mission. While the mission's footprint is too complex to be characterized by a single detection completeness, we extract ensemble completeness functions that recover the planet detections from previous work for stars between 3200 and 4000 K. We employ these completeness functions, together with a dual- population planet occurrence model that includes compact multiple planetary systems, to infer anew the planet yield. We predict both the number of M-dwarf planets likely from TESS and their system architectures. We report four main findings. First, TESS will likely detect more planets orbiting M dwarfs that previously predicted. Around stars with effective temperatures between 3200 and 4000 K, we predict that TESS will find 1274+/-241 planets orbiting 1026+/-182 stars, a 1.2-fold increase over previous predictions. Second, TESS will find two or more transiting planets around 20% of these host stars, a number similar to the multiplicity yield of NASA's Kepler mission. Third, TESS light curves in which one or more planets are detected will often contain transits of additional planets below the detection threshold of TESS. Among a typical set of 200 TESS hosts to one or more detected planets, 93+/-17 transiting planets will be missed. Transit follow-up efforts with the photometric sensitivity to detect an Earth or larger around a mid-M dwarf, even with very modest period completeness, will readily result in additional planet discoveries. Fourth, the strong preference of TESS for systems of compact multiples indicates that TESS planets will be dynamically cooler on average than Kepler planets, with 90% of TESS planets residing in orbits with e<0.15. We include both (1) a predicted sample of planets detected by TESS orbiting stars between 3200 and 4000 K, including additional nontransiting planets, or transiting and undetected planets orbiting the same star and (2) sample completeness functions for use by the community.
389. TGAS distances
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/3809
- Title:
- TGAS distances
- Short Name:
- J/MNRAS/478/3809
- Date:
- 10 Dec 2021 00:51:19
- Publisher:
- CDS
- Description:
- We derive unbiased distance estimates for the Gaia-TGAS data set by correcting for the bias due to the distance dependence of the selection function, which we measure directly from the data. From these distances and proper motions, we estimate the vertical and azimuthal velocities, W and V_{phi}_, and angular momentum L_z_ for stars in the Galactic centre and anticentre directions. The resulting mean vertical motion W^-^ hows a linear increase with both V_{phi}_ and L_z_ at 10{sigma} significance. Such a trend is expected from and consistent with the known Galactic warp. This signal extends to stars with guiding centre radii R_g_<R_0_, placing the onset of the warp at R<=7kpc. At equally high significance, we detect a previously unknown wave-like pattern of W^-^ over guiding centre R_g_ with an amplitude ~1km/s and a wavelength ~2.5kpc. This pattern is present in both the centre and anticentre directions, consistent with a winding (corrugated) warp or bending wave, likely related to known features in the outer disc (TriAnd and Monoceros overdensities), and may be caused by the interaction with the Sgr dwarf galaxy ~1Gyr ago. The only significant deviation from this simple fit is a stream-like feature near R_g_~9kpc (|L_z_|~2150kpc.km/s).
- ID:
- ivo://CDS.VizieR/J/BaltA/20/317
- Title:
- TGU 619 stars spectral types and distances
- Short Name:
- J/BaltA/20/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Interstellar extinction is investigated in a 1.5 square degree area of the Cepheus Flare in the direction of the dark cloud TGU 619 at l=102.5{deg}, b=+15.5{deg} . The study is based on photometric classification of 658 stars in spectral and luminosity classes down to V=16mag using photometry in the Vilnius seven-color system published in Paper I (2009BaltA..18..161Z, Cat. J/BaltA/18/161). The extinction in the investigated area is very uneven: in the most transparent directions we find an extinction of 0.3-1.1mag while in the darkest directions the maximum extinction observed is 2.6mag. The real extinction should be considerably larger since in the direction of some cloud clumps no stars are seen. The distribution of stars in the AV vs. d plot gives evidence that the dust clouds are located at a distance of 286+/-20pc.
