- ID:
- ivo://CDS.VizieR/J/MNRAS/439/2078
- Title:
- High-frequency A-type pulsators
- Short Name:
- J/MNRAS/439/2078
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a survey using the WASP archive to search for high-frequency pulsations in F-, A- and B-type stars. Over 1.5 million targets have been searched for pulsations with amplitudes greater than 0.5 millimagnitude. We identify over 350 stars which pulsate with periods less than 30min. Spectroscopic follow-up of selected targets has enabled us to confirm 10 new rapidly oscillating Ap stars, 13 pulsating Am stars and the fastest known {delta} Scuti star. We also observe stars which show pulsations in both the high-frequency domain and the low-frequency {delta} Scuti range. This work shows the power of the WASP photometric survey to find variable stars with amplitudes well below the nominal photometric precision per observation.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/381/1219
- Title:
- High mass-loss AGB stars in the Galactic Bulge
- Short Name:
- J/MNRAS/381/1219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of MSX point sources in the Galactic bulge (|l|<3deg, 1deg<|b|<5deg), observed in the A, C, D and E bands (8-21um), with a total area 48 square degrees and more than 7000 detected sources in the MSX D band (15 micron). We discuss the nature of the MSX sources [mostly asymptotic giant branch (AGB) stars], their luminosities, the interstellar extinction, the mass-loss rate distribution and the total mass-loss rate in the bulge. The mid-infrared data of MSX point sources have been combined with the near-infrared (J, H and Ks) data of Two Micron All Sky Survey. The cross-identification was restricted to Ks-band detected sources with Ks<=11mag. However, for those bright MSX D-band sources ([D]<4.0mag), which do not satisfy this criterion, we have set no Ks-band magnitude cut-off. The bolometric magnitudes and the corresponding luminosities of the MSX sources were derived by fitting blackbody curves. The relation between dM/dt and (Ks-[15])0 was used to derive the mass-loss rate of each MSX source in the bulge fields. Except for very few post-AGB stars, planetary nebulae and OH/IR stars, a large fraction of the detected sources at 15 micron (MSX D band) are AGB stars well above the red giant branch tip. A number of them show an excess in ([A]-[D])0 and (Ks-[D])0 colours, characteristic of mass-loss. These colours, especially (Ks-[D])0, enable estimation of the mass-loss rates (dM/dt) of the sources in the bulge fields which range from 10^-7^ to 10^-4^M_{sun}_/yr. Taking into consideration the completeness of the mass-loss rate bins, we find that the contribution to the integrated mass-loss is probably dominated by mass-loss rates larger than 3x10^-7^M_{sun}_/yr and is about 1.96x10^-4^M_{sun}_/yr/deg^2^ in the `intermediate' and `outer' bulge fields of sources with mass-loss rates, dM/dt>3x10^-7^M_{sun}_/yr. The corresponding integrated mass-loss rate per unit stellar mass is 0.48x10^-11^/yr. Apart from this, the various mid- and near-infrared colour-colour and colour-magnitude diagrams are discussed in the paper to study the nature of the stellar population in the MSX bulge fields.
- ID:
- ivo://CDS.VizieR/J/A+A/442/1135
- Title:
- High-mass X-ray binaries in the Magellanic Clouds
- Short Name:
- J/A+A/442/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of high-mass X-ray binaries in the Magellanic Clouds. The catalogue lists source name(s), coordinates, apparent magnitudes, orbital parameters, and X-ray luminosity of 128 high-mass X-ray binaries, together with stellar parameters of the components, other characteristic properties and a comprehensive selection of the relevant literature. The aim of this catalogue is to provide easy access to the basic information on the X-ray sources and their counterparts in other wavelength ranges (UV, optical, IR, radio). Most of the sources are identified to be Be/X-ray binaries. Some sources, however, are only tentatively identified as high-mass X-ray binaries on the basis of a transient character and/or a hard X-ray spectrum. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the high-mass nature of the X-ray binary this is mentioned. Literature published before 1 May 2005 has, as far as possible, been taken into account.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A81
- Title:
- High-mass X-ray binaries in the SMC
- Short Name:
- J/A+A/586/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The last comprehensive catalogue of high-mass X-ray binaries in the Small Magellanic Cloud (SMC) was published about ten years ago. Since then new such systems were discovered, mainly by X-ray observations with Chandra and XMM-Newton. For the majority of the proposed HMXBs in the SMC no X-ray pulsations were discovered as yet, and unless other properties of the X-ray source and/or the optical counterpart confirm their HMXB nature, they remain only candidate HMXBs. From a literature search we collected a catalogue of 148 confirmed and candidate HMXBs in the SMC and investigated their properties to shed light on their real nature. Based on the sample of well-established HMXBs (the pulsars), we investigated which observed properties are most appropriate for a reliable classification. We defined different levels of confidence for a genuine HMXB based on spectral and temporal characteristics of the X-ray sources and colour-magnitude diagrams from the optical to the infrared of their likely counterparts. We also took the uncertainty in the X-ray position into account. We identify 27 objects that probably are misidentified because they lack an infrared excess of the proposed counterpart. They were mainly X-ray sources with a large positional uncertainty. This is supported by additional information obtained from more recent observations. Our catalogue comprises 121 relatively high-confidence HMXBs (the vast majority with Be companion stars). About half of the objects show X-ray pulsations, while for the rest no pulsations are known as yet. A comparison of the two subsamples suggests that long pulse periods in excess of a few 100s are expected for the "non-pulsars", which are most likely undetected because of aperiodic variability on similar timescales and insufficiently long X-ray observations. The highest X-ray variability together with the lowest observed minimum fluxes for short-period pulsars indicate that in addition to the eccentricity of the orbit, its inclination against the plane of the Be star circum-stellar disc plays a major role in determining the outburst behaviour. The large population of HMXBs in the SMC, in particular Be X-ray binaries, provides the largest homogeneous sample of such systems for statistical population studies.
- ID:
- ivo://CDS.VizieR/J/AJ/143/128
- Title:
- High-metallicity M giant candidates from SDSS
- Short Name:
- J/AJ/143/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tidal stripping and three-body interactions with the central supermassive black hole may eject stars from the Milky Way. These stars would comprise a set of "intragroup" stars (IGS) that trace the past history of interactions in our galactic neighborhood. Using the Sloan Digital Sky Survey (SDSS) DR7 (Cat. II/294, superseded by Cat. V/139), we identify candidate solar-metallicity red giant intragroup stars using color cuts that are designed to exclude nearby M and L dwarfs. We present 677 intragroup candidates that are selected between 300kpc and 2Mpc, and are either the reddest intragroup candidates (M7-M10) or are L dwarfs at larger distances than previously detected.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/1829
- Title:
- High-precision transits of OGLE-TR-113b
- Short Name:
- J/ApJ/721/1829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present six new transits of the hot Jupiter OGLE-TR-113b observed with MagIC on the Magellan Telescopes between 2007 January and 2009 May. We update the system parameters and revise the planetary radius to R_p_=1.084+/-0.029R_J_, where the error is dominated by stellar radius uncertainties. The new transit midtimes reveal no transit timing variations from a constant ephemeris of greater than 13+/-28s over two years, placing an upper limit of 1-2M_{earth}_ on the mass of any perturber in a 1:2 or 2:1 mean-motion resonance with OGLE-TR-113b. Combining the new transit epochs with five epochs published between 2002 and 2006, we find hints that the orbital period of the planet may not be constant, with the best fit indicating a decrease of dP/dt=-60+/-15ms/yr. If real, this change in period could result from either a long-period (more than eight years) timing variation due to a massive external perturber or more intriguingly from the orbital decay of the planet. The detection of a changing period is still tentative and requires additional observations, but if confirmed it would enable direct tests of tidal stability and dynamical models of close-in planets.
- ID:
- ivo://CDS.VizieR/J/AJ/159/30
- Title:
- High proper-motion M-type stars spectroscopic obs.
- Short Name:
- J/AJ/159/30
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- Large numbers of low-to-medium-resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of empirically assembled M dwarf/subdwarf classification templates, based on the measurements of the TiO and CaH molecular bands near 7000{AA}, which are used to classify M dwarfs/subdwarfs by spectral type and metallicity class. We further present a pipeline to automatically determine the effective temperature Teff, metallicity [M/H], {alpha}-element to iron abundance ratio [{alpha}/Fe], and surface gravity logg of M dwarfs/subdwarfs using the latest version of BT-Settl model atmospheres. We apply these methods to a set of low-to-medium-resolution spectra of 1544 high proper-motion ({mu}>=0.4"/yr) M dwarfs/subdwarfs, collected at the MDM observatory, Lick Observatory, Kitt-Peak National Observatory, and Cerro-Tololo Interamerican Observatory.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/4054
- Title:
- High proper motion sources from WISE
- Short Name:
- J/MNRAS/454/4054
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The census of the solar neighbourhood is almost complete for stars and becoming more complete in the brown dwarf regime. Spectroscopic, photometric and kinematic characterization of nearby objects helps us to understand the local mass function, the binary fraction, and provides new targets for sensitive planet searches. We aim to derive spectral types and spectrophotometric distances of a sample of new high proper motion sources found with the WISE (Wide-field Infrared Survey Explorer) satellite, and obtain parallaxes for those objects that fall within the area observed by the Vista Variables in the Via Lactea survey (VVV). We used low-resolution spectroscopy and template fitting to derive spectral types, multiwavelength photometry to characterize the companion candidates and obtain photometric distances. Multi-epoch imaging from the VVV survey was used to measure the parallaxes and proper motions for three sources. We confirm a new T2 brown dwarf within ~15pc. We derived optical spectral types for 24 sources, mostly M dwarfs within 50pc. We addressed the wide binary nature of 16 objects found by the WISE mission and previously known high proper motion sources. Six of these are probably members of wide binaries, two of those are new, and present evidence against the physical binary nature of two candidate binary stars found in the literature, and eight that we selected as possible binary systems. We discuss a likely microlensing event produced by a nearby low-mass star and a galaxy, that is to occur in the following five years.
- ID:
- ivo://CDS.VizieR/J/ApJ/562/337
- Title:
- High proper-motion stars from MACHO astrometry
- Short Name:
- J/ApJ/562/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the preliminary results of our astrometric study of stellar motions along the lines of sight of the Magellanic Clouds and the Galactic bulge. Using 5 years of MACHO project point-spread function photometry, we find that we can easily select stars with proper motions of 0.03"/yr from these very dense fields, using the characteristic shapes of their light curves. By performing astrometry on photometrically selected, candidate, high proper motion (HPM) stars in 50 deg^2^, we have discovered 154 new HPM stars from ~55 million stars monitored by the MACHO project. These new objects have proper motions as high as 0.5"/yr, brightnesses ranging from V ~13 to V~19, and V-R colors between 0.3 and 1.45.
- ID:
- ivo://CDS.VizieR/J/MNRAS/318/1206
- Title:
- High proper motion stars in SA 94
- Short Name:
- J/MNRAS/318/1206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have applied the astrometric techniques devised by Murray (1986MNRAS.223..649M) for analysis of 48-inch Schmidt photographic data to SuperCOSMOS scans of UK Schmidt plates centred on Kapteyn's Selected Area 94 (RA=2h53m, DE=0{deg}). In this preliminary study, we combine astrometric data from four short-exposure V-band plates, taken in 1987 August (2 plates) and 1993 August (2 plates), with BVRI photometry from sky-limited plate material, to identify stars with proper motions exceeding 0.1"/yr. This paper discusses the completeness of the resulting sample and presents spectroscopy of 30 stars with {mu}>0.2"/yr. Based on the latter observations and the distribution in the [H_V_, (V-I)] reduced proper-motion diagram, we have classified stars in the complete sample as candidate white dwarfs, main-sequence dwarfs and halo subdwarfs, and derived estimates of the disc and halo luminosity functions.
