- 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 Individual radial velocities yet unpublished are listed in table 2.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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/150/168
- Title:
- Spectroscopy and photometry for HAT-P-50--HAT-P-53
- Short Name:
- J/AJ/150/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35M_J_ and radius of 1.29R_J_, and orbits a bright (V=11.8mag) M=1.27M_{sun}_, R=1.70R_{sun}_ star every P=3.1220days. The planet HAT-P-51b has a mass of 0.31M_J_ and radius of 1.29R_J_, and orbits a V=13.4mag, M=0.98M_{sun}_, R=1.04R_{sun}_ star with a period of P=4.2180days. The planet HAT-P-52b has a mass of 0.82M_J_ and radius of 1.01R_J_, and orbits a V=14.1mag, M=0.89M_{sun}_, R=0.89R_{sun}_ star with a period of P=2.7536days. The planet HAT-P-53b has a mass of 1.48M_J_ and radius of 1.32R_J_, and orbits a V=13.7mag, M=1.09M_{sun}_, R=1.21R_{sun}_ star with a period of P=1.9616days. All four planets are consistent with having circular orbits and have masses and radii measured to better than 10% precision. The low stellar jitter and favorable R_p_/R_{star}_ ratio for HAT-P-51 make it a promising target for measuring the Rossiter-McLaughlin effect for a Saturn-mass planet.
- ID:
- ivo://CDS.VizieR/J/AJ/152/88
- Title:
- Spectroscopy and photometry of HATS-11 and HATS-12
- Short Name:
- J/AJ/152/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V=14.1 G0-star shows a periodic 12.9mmag dip in its light curve every 3.6192days and a radial velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of 1.000+/-0.060M_{Sun}_, a radius of 1.444+/-0.057R_{Sun}_ and an effective temperature of 6060+/-150K, while its companion is a 0.85+/-0.12M_J_, 1.510+/-0.078R_J_ planet in a circular orbit. HATS-12 shows a periodic 5.1mmag flux decrease every 3.1428days and Keplerian radial velocities variations around a V=12.8 F-star. HATS-12 has a mass of 1.489+/-0.071M_{Sun}_, a radius of 2.21+/-0.21R_{Sun}_, and an effective temperature of 6408+/-75K. For HATS-12b, our measurements indicate that this is a 2.38+/-0.11M_J_, 1.35+/-0.17R_J_ planet in a circular orbit. Both host stars show subsolar metallicities of -0.390+/-0.060dex and -0.100+/-0.040dex, respectively, and are (slightly) evolved stars. In fact, HATS-11 is among the most metal-poor and, HATS-12, with a logg_*_ of 3.923+/-0.065, is among the most evolved stars hosting a hot-Jupiter planet. Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively).
- ID:
- ivo://CDS.VizieR/J/AJ/148/83
- Title:
- Spectroscopy in NGC 2360, NGC 3680, and NGC 5822
- Short Name:
- J/AJ/148/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary stars in open clusters are very useful targets in constraining the nucleosynthesis process. The luminosities of the stars are known because the distances of the clusters are also known, so chemical peculiarities can be linked directly to the evolutionary status of a star. In addition, binary stars offer the opportunity to verify a relationship between them and the straggler population in both globular and open clusters. We carried out a detailed spectroscopic analysis to derive the atmospheric parameters for 16 red giants in binary systems and the chemical composition of 11 of them in the open clusters NGC 2360, NGC 3680, and NGC 5822. We obtained abundances of C, N, O, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce, and Nd. The atmospheric parameters of the studied stars and their chemical abundances were determined using high-resolution optical spectroscopy. We employ the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. The abundances of the light elements were derived using the spectral synthesis technique. We found that the stars NGC 2360-92 and 96, NGC 3680-34, and NGC 5822-4 and 312 are yellow straggler stars. We show that the spectra of NGC 5822-4 and 312 present evidence of contamination by an A-type star as a secondary star. For the other yellow stragglers, evidence of contamination is given by the broad wings of the H{alpha}. Detection of yellow straggler stars is important because the observed number can be compared with the number predicted by simulations of binary stellar evolution in open clusters. We also found that the other binary stars are not s-process enriched, which may suggest that in these binaries the secondary star is probably a faint main-sequence object. The lack of any s-process enrichment is very useful in setting constraints for the number of white dwarfs in the open cluster, a subject that is related to the birthrate of these kinds of stars in open clusters and also to the age of a cluster. Finally, rotational velocities were also determined and their values were compared with those already determined for field giant stars.
- 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/ApJ/757/161
- Title:
- Spectroscopy of 56 exoplanet host stars
- Short Name:
- J/ApJ/757/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report homogeneous spectroscopic determinations of the effective temperature, metallicity, and projected rotational velocity for the host stars of 56 transiting planets. Our analysis is based primarily on the stellar parameter classification (SPC) technique. We investigate systematic errors by examining subsets of the data with two other methods that have often been used in previous studies (Spectroscopy Made Easy (SME) and MOOG). The SPC and SME results, both based on comparisons between synthetic spectra and actual spectra, show strong correlations between T_eff_, [Fe/H], and log g when solving for all three quantities simultaneously. In contrast the MOOG results, based on a more traditional curve-of-growth approach, show no such correlations. To combat the correlations and improve the accuracy of the temperatures and metallicities, we repeat the SPC analysis with a constraint on log g based on the mean stellar density that can be derived from the analysis of the transit light curves. Previous studies that have not taken advantage of this constraint have been subject to systematic errors in the stellar masses and radii of up to 20% and 10%, respectively, which can be larger than other observational uncertainties, and which also cause systematic errors in the planetary mass and radius.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/107
- Title:
- Spectroscopy of faint KOI stars
- Short Name:
- J/ApJ/771/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar properties are measured for a large set of Kepler mission exoplanet candidate host stars. Most of these stars are fainter than 14th magnitude, in contrast to other spectroscopic follow-up studies. This sample includes many high-priority Earth-sized candidate planets. A set of model spectra are fitted to R~3000 optical spectra of 268 stars to improve estimates of T_eff_, log(g), and [Fe/H] for the dwarfs in the range 4750<=T_eff_<=7200K. These stellar properties are used to find new stellar radii and, in turn, new radius estimates for the candidate planets. The result of improved stellar characteristics is a more accurate representation of this Kepler exoplanet sample and identification of promising candidates for more detailed study. This stellar sample, particularly among stars with T_eff_>~5200K, includes a greater number of relatively evolved stars with larger radii than assumed by the mission on the basis of multi-color broadband photometry. About 26% of the modeled stars require radii to be revised upward by a factor of 1.35 or greater, and modeling of 87% of the stars suggest some increase in radius. The sample presented here also exhibits a change in the incidence of planets larger than 3-4R_{Earth}_ as a function of metallicity. Once [Fe/H] increases to >=-0.05, large planets suddenly appear in the sample while smaller planets are found orbiting stars with a wider range of metallicity.
- ID:
- ivo://CDS.VizieR/J/AJ/156/257
- Title:
- Spectroscopy of RGB stars in Draco & Ursa Minor
- Short Name:
- J/AJ/156/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measuring the frequency of binary stars in dwarf spheroidal galaxies (dSphs) requires data taken over long time intervals. We combine radial velocity measurements from five literature sources taken over the course of ~30 years to yield the largest multi-epoch kinematic sample for stars in the dSphs Draco and Ursa Minor. With this data set, we are able to implement an improved version of the Bayesian technique described in Spencer et al. (2017, J/AJ/153/254) to evaluate the binary fraction of red giant stars in these dwarf galaxies. Assuming Duquennoy & Mayor (1991A&A...248..485D) period and mass ratio distributions, the binary fractions in Draco and Ursa Minor are 0.50_-0.06_^+0.04^ and 0.78_-0.08_^+0.09^, respectively. We find that a normal mass ratio distribution is preferred over a flat distribution, and that log-normal period distributions centered on long periods ({mu}_logP_>3.5) are preferred over distributions centered on short ones. We reanalyzed the binary fractions in Leo II, Carina, Fornax, Sculptor, and Sextans, and find that there is <1% chance that binary fraction is a constant quantity across all seven dwarfs, unless the period distribution varies greatly. This indicates that the binary populations in Milky Way dSphs are not identical in regard to their binary fractions, period distributions, or both. We consider many different properties of the dwarfs (e.g., mass, radius, luminosity, etc.) and find that binary fraction might be larger in dwarfs that formed their stars quickly and/or have high velocity dispersions.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A138
- Title:
- Spectroscopy of spectroscopic binaries
- Short Name:
- J/A+A/563/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present knowledge of stellar properties and dynamical structure of early-type multiple stellar systems is insufficient to offer useful statistical constraints for stellar formation models. To increase the amount of observational information about the characteristics of early-type multiples, we carried out a spectroscopic monitoring to search for new spectroscopic components and to determine their orbits. We observed 30 early-type multiple systems using the 2.15m telescope and REOSC echelle spectrograph at the Complejo Astronomico El Leoncito (CASLEO) during 10 observing runs between 2008 and 2013. We measured radial velocities by cross-correlations and applied a spectral disentangling method to double-lined systems. We calculated orbital elements for the inner subsystem of each analysed multiple. In this first paper we present calculated orbits for six previously catalogued subsystems. Three subsystems had no previously published parameters, while we obtained more accurate orbits for the other three. In one case we found absolute masses and radii for the components by using available photometric data. The long-term spectroscopic monitoring of multiple systems is a useful method of investigating the companions in intermediate hierarchical levels, particularly those that could affect the dynamical evolution of a close inner binary subsystem.
- ID:
- ivo://CDS.VizieR/J/AJ/152/10
- Title:
- Spectroscopy of subsystems in four multiple stars
- Short Name:
- J/AJ/152/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven spectroscopic orbits in nearby solar-type multiple stars are presented. The primary of the chromospherically active star HIP9642 is a 4.8day double-lined pair; the outer 420 year visual orbit is updated, but remains poorly constrained. HIP12780 is a quadruple system consisting of the resolved 6.7year pair FIN 379 Aa,Ab, for which the combined orbit, masses, and orbital parallax are determined here, and the single-lined binary Ba,Bb with a period of 27.8 days. HIP28790 is a young quintuple system composed of two close binaries, Aa,Ab and Ba,Bb, with periods of 221 and 13 days, respectively, and a single distant component C. Its subsystem Ba,Bb is peculiar, having a spectroscopic mass ratio of 0.89 but a magnitude difference of ~2.2mag. HIP64478 also contains five stars: the A-component is a 29year visual pair with a previously known 4 day twin subsystem, while the B-component is a contact binary with a period of 5.8hr, seen nearly pole-on.
