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- ID:
- ivo://CDS.VizieR/J/AJ/132/663
- Title:
- Differential Velocities of very low mass SBs
- Short Name:
- J/AJ/132/663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of a survey for radial velocity variability in a heterogeneous sample of very low mass stars and brown dwarfs. One distinguishing characteristic of the survey is its time span, which allows an overlap between spectroscopic binaries and those that can be found by high angular resolution imaging. Despite our relatively low velocity precision, we are able to place a new constraint on the total binary fraction in these objects, which suggests that they are more likely the result of extending the same processes at work at higher masses into this mass range, rather than a distinct mode of formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/686/1280
- Title:
- Discovery of hot subdwarf companion to FY CMa
- Short Name:
- J/ApJ/686/1280
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The rapid rotation of Be stars may be caused in some cases by past mass and angular momentum accretion in an interacting binary in which the mass donor is currently viewed as a small, hot subdwarf stripped of its outer envelope. Here we report on the spectroscopic detection of such a subdwarf in the Be binary system FY Canis Majoris from the analysis of data acquired by the IUE spacecraft and KPNO Coude Feed Telescope over the course of 16 and 21yr, respectively. We present a double-lined spectroscopic orbit for the binary based on radial velocities from the IUE spectra and use the orbital solutions with a Doppler tomography algorithm to reconstruct the components' UV spectra. The subdwarf is hot (T_eff_=45+/-5kK) and has a mass of about 1.3M_{sun}_ and a radius of about 0.6R_{sun}_. It contributes about 4% as much flux as the Be star does in the FUV. We also present observations of the H{alpha} and HeI{lambda}6678 emission features that are formed in the circumstellar disk of the Be star.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A85
- Title:
- Disentangled spectra of R145
- Short Name:
- J/A+A/598/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first SB2 orbital solution and disentanglement of the massive Wolf-Rayet binary R145 (P=159d) located in the Large Magellanic Cloud. The primary was claimed to have a stellar mass greater than 300M_{sun}_, making it a candidate for the most massive star known. While the primary is a known late type, H-rich Wolf-Rayet star (WN6h), the secondary could not be so far unambiguously detected. Using moderate resolution spectra, we are able to derive accurate radial velocities for both components. By performing simultaneous orbital and polarimetric analyses, we derive the complete set of orbital parameters, including the inclination. The spectra are disentangled and spectroscopically analyzed, and an analysis of the wind-wind collision zone is conducted.
55. DL Cas
- ID:
- ivo://CDS.VizieR/J/AJ/107/2093
- Title:
- DL Cas
- Short Name:
- J/AJ/107/2093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As an eight-day Cepheid which is both a component of a spectroscopic binary and a member of the open cluster NGC 129, DL Cas is potentially a very accurate calibrator of the period-luminosity (PL) relation and Cepheid mass. From 160 high-precision (sigma<1.5km/s) radial velocity observations made with the CORAVEL and DAO spectrometers - including 67 new unpublished data - we have obtained both the orbital and pulsational velocity curves of this binary Cepheid. This body of RV data makes DL Cas one of the best observed Cepheids in our galaxy. Our analysis yields an orbital period of 684.4+/-0.4days which confirms DL Cas as one of the shortest-period binaries containing a Cepheid. We derive new precise orbital elements which replace earlier preliminary values found by Harris et al. Isochrone fitting to the V,B-V data points of Turner et al. yields an age of NGC 129 of (7.6+/-0.4)x10^7^yr and a Cepheid mass of 5.6M_{sun}_. Evidence from age, a possible period change, and strip crossing times suggest that DL Cas is a solar-abundance star making its third (redward) crossing through the Cepheid instability strip. Existing observational constraints from our mass function of the DL Cas system and an IUE spectrum suggest that the companion is a main sequence star in the mass range from 2.6 to 5.6M_{sun}_. We use the pulsational velocity curve and published photometry to derive the distance and mean radius of DL Cas with the surface brightness method, finding values of 2034+/-110pc and 66.0+/-3.5R_{sun}_, respectively. The radius we derive indicates that DL Cas is a fundamental-mode pulsator, removing any possible ambiguity in mode identification. The distance corresponds to a mean absolute visual magnitude of <Mv>=-4.2+/-0.3mag whose error is dominated by the uncertainty of the absorption correction. Since our very precise distance contributes only 0.12mag to the error in <Mv>, improved reddening studies of NGC 129 would make DL Cas a very tight calibrator of the PL relation. Our value of the gamma velocity of the DL Cas system is identical to the mean radial velocity of the stars in NGC 129, strengthening the case for cluster membership. However, our distance for DL Cas, and thus for NGC 129, is significantly larger than the 1670+/-13pc obtained by Turner et al. from ZAMS fitting of the cluster. Possible causes for this discrepancy, and their implications for Cepheid distance scale calibrations, are discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A53
- Title:
- 1-D optical spectra for IRAS19135+3937
- Short Name:
- J/A+A/631/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to determine the geometry, density gradient, and velocity structure of jets in post-asymptotic giant branch (post-AGB) binaries. Our high cadence time series of high-resolution optical spectra of jet-creating post-AGB binary systems provide us with a unique tomography of the jet. We determine the spatio-kinematic structure of the jets based on these data by fitting the synthetic spectral line profiles created by our model to the observed, orbital phase-resolved, H{alpha}-line profiles of these systems. The fitting routine is provided with an initial spectrum and is allowed to test three configurations, derived from three specific jet launching models: a stellar jet launched by the star, an X-wind, and a disk wind configuration. We apply a Markov-chain Monte Carlo routine in order to fit our model to the observations. Our fitting code is tested on the post-AGB binary IRAS19135+3937. We find that a model using the stellar jet configuration gives a marginally better fit to our observations. The jet has a wide half-opening angle of about 76 degrees and reaches velocities up to 870km/s. Our methodology is successful in determining some parameters for jets in post-AGB binaries. The model for IRAS19135+3937 includes a transparent, low density inner region (for a half-opening angle <40{deg}). The source feeding the accretion disk around the companion is most likely the circumbinary disk. We will apply this jet fitting routine to other jet-creating post-AGB stars in order to provide a more complete description of these objects. We aim at describing and understanding binary interaction processes in systems with very evolved companions. Here, we focus on understanding the origin and determining the properties of the high-velocity outflow observed in one such system.
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/2709
- Title:
- Double-lined spectroscopic binaries catalog
- Short Name:
- J/MNRAS/492/2709
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of a selected set of 69 double-lined spectroscopic binaries (SB2) with well defined visual and spectroscopic orbits was carried out. The orbital parallax, the mass, the colour, and the luminosity of each component were derived from observational data for almost all of these systems. We have also obtained an independent estimation of the component masses by comparing the colour-luminosity diagram (CMD) to the stellar evolution tracks reported by Pietrinferni. Nearly all of the observational points on the CMD are located between two tracks of slightly different mass or which fall very close to the one corresponding to a unique mass value. The masses obtained from the stellar model are in good agreement with their empirical values determined by parallax techniques (orbital, dynamical, and Gaia). This means that our adopted model is rather reliable and can therefore be used to infer further information, such as the age of each component in the studied systems. Our results indicate a fair correspondence between the age of primaries and secondary stars within 3{sigma}. Nevertheless, we caution that these age indications suffer of uncertainties due to both inhomogeneities/low precision of the adopted photometric data and possible systematics. Finally, it is statistically shown that along with the orbital and trigonometric parallaxes, the dynamical parallax can serve as a reliable tool for distance estimates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/510/1515
- Title:
- Double-lined spectroscopic binaries in M11
- Short Name:
- J/MNRAS/510/1515
- Date:
- 10 Jan 2022 09:23:04
- Publisher:
- CDS
- Description:
- We have developed a new method for spectral analysis of binaries. Our method successfully identifiesSB2 candidates from high-resolution Gaia-ESO spectra. Compared to the commonly used cross-correlation function analysis, it works for binaries with rapidly rotating components. We test our method on synthetic and observational spectra of BAFG-stars with vsin(i) from 1 to 330km/s in the open cluster M11. We confirm five previously detected SB2 candidates and find 19 new ones. For three SB2 candidates we find circular orbits and obtain dynamical mass ratios.
- ID:
- ivo://CDS.VizieR/III/278
- Title:
- Double stars with wide separations in the AGK3
- Short Name:
- III/278
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large list of common proper motion stars selected from the third Astronomischen Gesellschaft Katalog (AGK3) was monitored with the CORAVEL (for COrrelation RAdial VELocities) spectrovelocimeter, in order to prepare a sample of physical binaries with very wide separations. In paper I,66 stars received special attention, since their radial velocities (RV) seemed to be variable. These stars were monitored over several years in order to derive the elements of their spectroscopic orbits. In addition, 10 of them received accurate RV measurements from the SOPHIE spectrograph of the T193 telescope at the Observatory of Haute-Provence. For deriving the orbital elements of double-lined spectroscopic binaries (SB2s), a new method was applied, which assumed that the RV of blended measurements are linear combinations of the RV of the components. 13 SB2 orbits were thus calculated. The orbital elements were eventually obtained for 52 spectroscopic binaries (SBs), two of them making a triple system. 40 SBs received their first orbit and the orbital elements were improved for 10 others. In addition, 11 SBs were discovered with very long periods for which the orbital parameters were not found. It appeared that HD 153252 has a close companion, which is a candidate brown dwarf with a minimum mass of 50 Jupiter masses. In paper II, 80 wide binaries (WBs) were detected, and 39 optical pairs were identified. Adding CPM stars with separations close enough to be almost certain they are physical, a "bias-controlled" sample of 116 wide binaries was obtained, and used to derive the distribution of separations from 100 to 30,000 au. The distribution obtained doesn't match the log-constant distribution, but is in agreement with the log-normal distribution. The spectroscopic binaries detected among the WB components were used to derive statistical informations about the multiple systems. The close binaries in WBs seem to be similar to those detected in other field stars. As for the WBs, they seem to obey the log-normal distribution of periods. The number of quadruple systems is in agreement with the "no correlation" hypothesis; this indicates that an environment conducive to the formation of WBs doesn't favor the formation of subsystems with periods shorter than 10 years.
- ID:
- ivo://CDS.VizieR/J/A+A/333/658
- Title:
- D-type symbiotic stars emission line fluxes
- Short Name:
- J/A+A/333/658
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of five D-type symbiotics are presented: three oxygen Mira (He2-38, H2-38 and H1-36) and two carbon Mira symbiotics (AS 210 and SS 38). The observations in the spectral range between 3200{AA} and 7400{AA} show the presence of several emission lines in various states of excitation. A line list is provided with their suggested identifications. Several parameters were derived for each object: interstellar reddening as determined from Balmer decrement and He II lines, temperature and electronic density, abundance ratios of Ne/O, Ar/O, Fe/Ne, N/O and He/H. We found nitrogen enrichment while for the other elements their abundances are compatible with solar, except iron which is depleted. We did not detect significant changes in the line and in the continuos spectra of the stars analyzed here, except for He2-38, which increased its degree of excitation compared to Allen's (1984PASAu...5..562N) catalogue.
