- ID:
- ivo://CDS.VizieR/J/AJ/152/207
- Title:
- Spectroscopic Indicators in SeisMic Archive (SISMA)
- Short Name:
- J/AJ/152/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We created a large database of physical parameters and variability indicators by fully reducing and analyzing the large number of spectra taken to complement the asteroseismic observations of the COnvection, ROtation and planetary Transits (CoRoT) satellite. 7103 spectra of 261 stars obtained with the ESO echelle spectrograph HARPS have been stored in the VO-compliant database Spectroscopic Indicators in a SeisMic Archive (SISMA), along with the CoRoT photometric data of the 72 CoRoT asteroseismic targets. The remaining stars belong to the same variable classes of the CoRoT targets and were observed to better characterize the properties of such classes. Several useful variability indicators (mean line profiles, indices of differential rotation, activity and emission lines) together with vsini and radial-velocity measurements have been extracted from the spectra. The atmospheric parameters T_eff_,logg, and [Fe/H] have been computed following a homogeneous procedure. As a result, we fully characterize a sample of new and known variable stars by computing several spectroscopic indicators, also providing some cases of simultaneous photometry and spectroscopy.
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- ID:
- ivo://CDS.VizieR/J/AJ/152/46
- Title:
- Spectroscopic orbits for 15 late-type stars
- Short Name:
- J/AJ/152/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic orbital elements are determined for 15 stars with periods from 8 to 6528days with six orbits computed for the first time. Improved astrometric orbits are computed for two stars and one new orbit is derived. Visual orbits were previously determined for four stars, four stars are members of multiple systems, and five stars have Hipparcos "G" designations or have been resolved by speckle interferometry. For the nine binaries with previous spectroscopic orbits, we determine improved or comparable elements. For HD28271 and HD200790, our spectroscopic results support the conclusions of previous authors that the large values of their mass functions and lack of detectable secondary spectrum argue for the secondary in each case being a pair of low-mass dwarfs. The orbits given here may be useful in combination with future interferometric and Gaia satellite observations.
- ID:
- ivo://CDS.VizieR/J/AJ/156/117
- Title:
- Spectroscopic orbits for late-type stars. II.
- Short Name:
- J/AJ/156/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined spectroscopic orbital elements for 13 systems - 10 single-lined binaries and three double-lined binaries. For the three binaries with previously published spectroscopic orbits, we have computed improved or comparable elements. While two systems have relatively short periods between 10 and 19 days, the remaining systems have much longer periods ranging from 604 to 9669 days. One of the single-lined systems, HD 142640, shows both short-period and long-period velocity variations and so is triple. For three systems - HD 59380, HD 160933, and HD 161163 - we have combined our spectroscopic results with Hipparcos astrometric observations to obtain astrometric orbits. For HD 14802 we have determined a joint orbital solution from spectroscopic velocities and interferometric observations. The orbits given here will be useful in combination with future interferometric and Gaia satellite observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/466/415
- Title:
- Spectroscopic orbits for three binaries
- Short Name:
- J/ApJ/466/415
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present orbital solutions for three low-amplitude spectroscopic binaries discovered in a sample of 20 solar-type IAU radial velocity standard stars observed with the Digital Speedometers at the Harvard- Smithsonian Center for Astrophysics. We update the orbital solutions for HD 114762 and HD 140913, and present a preliminary new solution for HD 29587. For all three orbits, the minimum mass for the secondary is less than 0.08M_{sun}_, the borderline between stellar and substellar masses. We consider the probability that all three binaries have small enough inclination angles so that their companions are above the substellar limit. To do so, we treat the 20 IAU standards as a sample drawn from a population of binaries with a mass-ratio distribution that does not allow any substellar companions. We calculate the probability that such a sample could still have three binaries, with the low-amplitude orbits actually found within the IAU sample. We show that this probability is small, depending on the specific mass-ratio distribution. For example, a flat mass-ratio distribution that assumes there are no substellar companions can be excluded at a high confidence level, 99.7%. We further show that our three detections may imply that the secondary-mass distribution rises near the substellar limit. However, the observations do not yet allow us to distinguish whether the unseen companions of HD 114762, HD 140913, and HD 29587 have stellar or substellar masses. In particular, recent attempts to estimate the mass of the companion of HD 114762 based on assumptions about the intrinsic rotation of the primary are inconclusive, and the companion could easily have a mass as low as 0.02M_{sun}_. We compare our three detections with the null results of four very precise radial velocity searches for substellar companions. The difference is indeed puzzling but can be accounted for if just a small fraction of the solar-type stars, of the order of a few percent, have companions with masses near the substellar limit.
- ID:
- ivo://CDS.VizieR/J/ApJ/652/681
- Title:
- Spectroscopic subcomponents in multiple systems
- Short Name:
- J/ApJ/652/681
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a methodology for analyzing triple stellar systems that include a visual double star wherein one of the components is a single- or double-lined spectroscopic binary. By using this methodology, we can calculate the most probable values of the spectroscopic binary's inclination, the angular separation between its components, and its stellar masses, and we can even estimate the spectral types. For a few W UMa-type eclipsing binaries, stellar radii are also determined. Moreover, we present new formulae for calculating stellar masses depending on spectral type. In this way we have studied 61 triple systems, five of them W UMatype eclipsing binaries with low-mass subcomponents. In addition, we study nine quadruple systems, applying the same methodology and considering them twice as a triple system.
- ID:
- ivo://CDS.VizieR/J/A+A/382/118
- Title:
- Spectroscopic sub-systems in multiple stars
- Short Name:
- J/A+A/382/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large sample of visual multiples of spectral types F5-M has been surveyed for the presence of spectroscopic sub-systems. In table 1 we provide basic identifiers for the components or their combinations, average radial velocities, parameters of correlation dips and analysis of the velocity variability and physical relation. Notes contain comments and additional identifiers. Individual radial velocities yet unpublished are listed in table 2. Table 6 is extracted from the Multiple Star Catalog (Cat. <J/A+AS/124/75>) for the analysis of the statistics of spectroscopic+visual multiple stellar systems.
- ID:
- ivo://CDS.VizieR/J/AJ/112/1489
- Title:
- Spectroscopic survey for binaries in NGC 5053
- Short Name:
- J/AJ/112/1489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried our a radial velocity survey for spectroscopic binaries in the low-density globular cluster NGC 5053. Our sample contains a total of 77 cluster member giant and subgiant stars with visual magnitudes of 14.5-18.6. Of These 77 stars, 66 stars have on average of 3-4 measurements with a total of 236 velocities. A typical velocity error per measurement is 13km/s. The stars in our sample are spatially distributed from the cluster center out to 10arcmin in radius (4.5 core radii). Among theses 66 stars with multiple velocity measurements, we discovered 6 spectroscopic binary candidates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/385/2210
- Title:
- Spectroscopy around lam Ori and sig Ori
- Short Name:
- J/MNRAS/385/2210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained multi-epoch, high-resolution spectroscopy of 218 candidate low-mass stars and brown dwarfs (BDs) in the young clusters around {lambda} Ori and {sigma} Ori. We find that 196 targets are cluster members based on their radial velocity, the equivalent width of their NaI 8200 lines and the spectral type from their TiO band strength. We have identified 11 new binary stars among the cluster members based on their variable radial velocity and an additional binary from the variation in its linewidth and shape. Of these, six are double-lined spectroscopic binaries (SB2) where the components of the binary are of comparable brightness. The others are single-lined binaries (SB1) in which the companion is faint or the spectra of the stars are blended. There are three narrow-lined SB1 binaries in our sample for which the companion is more than 2.5mag fainter than the primary.
- ID:
- ivo://CDS.VizieR/J/AJ/151/3
- Title:
- Spectroscopy of binary stars
- Short Name:
- J/AJ/151/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young, intermediate-mass stars are experiencing renewed interest as targets for direct-imaging planet searches. However, these types of stars are part of multiple systems more often than not. Close stellar companions affect the formation and orbital architecture of planetary systems, and the properties of the companions can help constrain the binary formation mechanism. Unfortunately, close companions are difficult and expensive to detect with imaging techniques. In this paper, we describe the direct spectral detection method wherein a high-resolution spectrum of the primary is cross-correlated against a template for a companion star. Variants of this method have previously been used to search for stellar, brown dwarf, and even planetary companions. We show that the direct spectral detection method can detect companions as late as M-type orbiting A0 or earlier primary stars in a single epoch on small-aperture telescopes. In addition to estimating the detection limits, we determine the sources of uncertainty in characterizing the companion temperature, and find that large systematic biases can exist. After calibrating the systematic biases with synthetic binary star observations, we apply the method to a sample of 34 known binary systems with an A- or B-type primary star. We detect nine total companions, including four of the five known companions with literature temperatures between 4000K<T<6000K, the temperature range for which our method is optimized. We additionally characterize the companion for the first time in two previously single-lined binary systems and one binary identified with speckle interferometry. This method provides an inexpensive way to use small-aperture telescopes to detect binary companions with moderate mass ratios, and is competitive with high-resolution imaging techniques inside ~100-200mas.
- ID:
- ivo://CDS.VizieR/J/AJ/152/40
- Title:
- Spectroscopy of 341 bright A- and B-type stars
- Short Name:
- J/AJ/152/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary stars and higher-order multiple systems are a ubiquitous outcome of star formation, especially as the system mass increases. The companion mass-ratio distribution is a unique probe into the conditions of the collapsing cloud core and circumstellar disk(s) of the binary fragments. Inside a~1000AU the disks from the two forming stars can interact, and additionally companions can form directly through disk fragmentation. We should, therefore, expect the mass-ratio distribution of close companions (a<~100AU) to differ from that of wide companions. This prediction is difficult to test using traditional methods, in particular, with intermediate-mass primary stars, for a variety of observational reasons. We present the results of a survey searching for companions to A- and B-type stars using the direct spectral detection method, which is sensitive to late-type companions within ~1'' of the primary and which has no inner working angle. We estimate the temperatures and surface gravity of most of the 341 sample stars and derive their masses and ages. We additionally estimate the temperatures and masses of the 64 companions we find, 23 of which are new detections. We find that the mass-ratio distribution for our sample has a maximum near q~0.3. Our mass-ratio distribution has a very different form than in previous works, where it is usually well-described by a power law, and indicates that close companions to intermediate-mass stars experience significantly different accretion histories or formation mechanisms than wide companions.
