- ID:
- ivo://CDS.VizieR/J/A+A/588/A10
- Title:
- HD 149404 FEROS, Coralie and IUE spectra
- Short Name:
- J/A+A/588/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass and momentum exchanges in close massive binaries play an important role in their evolution, and produce several observational signatures such as asynchronous rotation and altered chemical compositions, that remain after the stars detach again. We investigated these effects for the detached massive O-star binary HD 149404 (O7.5 If + ON9.7 I, P=9.81-days), which is thought to have experienced a past episode of case A Roche-lobe overflow (RLOF). Using phase-resolved spectroscopy, we performed the disentangling of the optical spectra of the two stars. The reconstructed primary and secondary spectra were then analysed with the CMFGEN model atmosphere code to determine stellar parameters, such as the effective temperatures and surface gravities, and to constrain the chemical composition of the components. We complemented the optical study with the study of IUE spectra, which we compare to the synthetic binary spectra. The properties of the stars were compared to evolutionary models.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/567/A57
- Title:
- HD 161306 H{alpha} and HeI spectra
- Short Name:
- J/A+A/567/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectrum of the Be star HD 161306 is shown to vary periodically with a period of ~100-days. The radial velocity of the HeI 6678{AA} emission peak varying in antiphase to the radial velocity of the H{alpha} emission wings component suggests that the star is a binary similar to {phi} Per, 59 Cyg, or FY CMa, i.e. a radiatively interacting Be binary - a rare case among Be stars. This type of object is also called a {phi} Per-type binary or Be + sdO binaries. The range of radial-velocity variations of the strong emission peak in the helium line observed in HD 161306 is about 180km/s, similar to what is observed for these systems. We therefore conclude that HD 161306 may represent another case of a Be star with a hot subdwarf companion.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A97
- Title:
- HD 183656 Long-term variations
- Short Name:
- J/A+A/647/A97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the latest results of a long-term observational project aimed at observing, collecting from the literature, and homogenising the light, colour, and spectral variations of the well-known emission-line Be star V923 Aql. Our analysis of these parameters confirms that all of the observables exhibit cyclic changes with variable cycle length between about 1800 and 3000 days, so far documented for seven consecutive cycles. We show that these variations can be qualitatively understood within the framework of the model of one-armed oscillation of the circumstellar disk, with a wave of increased density and prograde revolution in space. We confirm the binary nature of the object with a 214.716 day period and estimate the probable system properties. We also confirm the presence of rapid light, and likely also spectral changes. However, we cannot provide any firm conclusions regarding their nature. A quantitative modelling study of long-term changes is planned as a follow-up to this work.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A94
- Title:
- HD 96446 radial velocities
- Short Name:
- J/A+A/626/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD 96446 is a magnetic B2p He-strong star that has been reported to be a {beta} Cep pulsator. We present a detailed spectroscopic analysis of this object based on an intensive observational data set obtained in a multisite campaign with the spectrographs CORALIE, FEROS, and HARPS (La Silla); UVES (Paranal); HERCULES (Mt. John Observatory); and GIRAFFE (SAAO). Radial velocities were measured by cross-correlations and analysed to detect periodic variations. On the other hand, the mean spectrum was fit with spectral synthesis to derive atmospheric parameters and chemical abundances. From the analysis of radial velocities, HD 96446 was found to be a spectroscopic binary with a period of 799 days. The stellar companion, which contributes only ~5% of the total flux, is an A0-type star. A frequency analysis of the radial velocities allowed us to detect two pulsational modes with periods 2.23h and 2.66h. The main mode is most probably a low-inclination, dipole mode (l, m) = (1, 0), and the second pulsation mode corresponds to (l, m) = (2, 2) or to a pole-on (l, m) = (3, 2) configuration. In addition to radial velocities, the main pulsation mode is evidenced through small variations in the spectral morphology (temperature variations) and the light flux. The rotation period of 23.4d, was detected through the variation in line intensities. Chemical abundances are unevenly distributed over the stellar surface, with helium concentrated at the negative magnetic pole and most metals strengthened at lower latitudes. The mean chemical abundance of helium is strongly abnormal, reaching a value of 0.60 (number fraction).
- ID:
- ivo://CDS.VizieR/J/A+A/615/A19
- Title:
- HD54662 radial velocities and X-ray light curves
- Short Name:
- J/A+A/615/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD 54662 is an O-type binary star belonging to the CMa OB1 association. Due to its long-period orbit, this system is an interesting target to test the adiabatic wind shock model. The goal of this study is to improve our knowledge of the orbital and stellar parameters of HD 54662 and to analyze its X-ray emission to test the theoretical scaling of X-ray emission with orbital separation for adiabatic wind shocks. A spectral disentangling code is applied to a set of optical spectra to determine the radial velocities, as well as the individual spectra of the primary and secondary stars. The orbital solution of the system is established and the reconstructed individual spectra are analyzed by means of the CMFGEN model atmosphere code. Two X-ray spectra are fitted using a Markov Chain Monte Carlo algorithm and are compared to the emission expected from adiabatic shocks. We determine an orbital period of 2103.4 days, a surprisingly low orbital eccentricity of 0.11, and a mass ratio m_2/m_1 of 0.84. Combined with the orbital inclination inferred in a previous astrometric study, we obtain surprisingly low masses of 9.7 and 8.2M_{sun}_. From the disentangled primary and secondary spectra, we infer O6.5 spectral types for both stars with the primary being about two times brighter than the secondary. The softness of the X-ray spectra for the two observations, the very small variation of best-fitting spectral parameters and the comparison of the X-ray-to- bolometric luminosity ratio with the canonical value for O-type stars allow us to conclude that the X-ray emission from the wind interaction region is quite small and that the observed emission is rather dominated by the intrinsic emission from the stars. Computing the peculiar radial and intrinsic emission from the stars. Computing the peculiar radial and tangential velocities, we cannot confirm the runaway status previously attributed to HD 54662. We find no X-ray emission associated with the bow shock detected in the infrared. The lack of hard X-ray emission from the wind-shock region suggests that the mass-loss rates are lower than expected and/or that the pre-shock wind velocities are much lower than the terminal wind velocities. The bow shock associated with HD 54662 possibly corresponds to a wind-blown arc created by the interaction of the stellar winds with the ionized gas of the CMa OB1 association rather than by a large differential velocity between the binary and the surrounding interstellar medium.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/1300
- Title:
- HD 165052 radial-velocity measurements
- Short Name:
- J/MNRAS/433/1300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of radial-velocity measurements of the spectroscopic binary star HD 165052 obtained by disentangling of high-resolution optical spectra. The longitude of the periastron ({varpi}=60+/-2{deg}) shows a variation with respect to previous studies. We have determined the apsidal motion rate of the system {dot{varpi}}=12.1+/-0.3{deg}/yr, which was used to calculate the absolute masses of the binary components: M_1_=22.5+/-1.0M_{sun}_ and M_2_=20.5+/-0.9M_{sun}_. Analysing the separated spectra we have re-classified the components as O7Vz and O7.5Vz stars.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1557
- Title:
- HD 46703 spectroscopy and photometry
- Short Name:
- J/AJ/136/1557
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The metal-poor post-asymptotic giant branch (AGB) star HD 46703 is shown to be a single-line spectroscopic binary with a period of 600-days, a high velocity of -94km/s, and an orbital eccentricity of 0.3. Light-curve studies show that it also pulsates with a period of 29-days. High-resolution, high signal-to-noise spectra were used for a new abundance study.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A116
- Title:
- HD50138 time-dependent spectral variations
- Short Name:
- J/A+A/586/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B[e] stars are anomalous objects around which extended circumstellar matter is present. The observed properties of the central star are significantly affected by the surrounding material. Therefore, the use of standard synthetic spectra is disputable in this case and our capability to study these objects is limited. One of the possibilities is to analyse variations of the spectral features. Long-term spectroscopic observations are required for this, but are not found in the literature. For our study we choose the B[e] star HD 50138 of the FS CMa type because of the indication that this star is a post-main-sequence star, although still not highly evolved. Therefore, it can be a good object for testing evolutionary models. Currently, HD 50138 is the most extensively observed FS CMa star which makes it an ideal object for modelling. Our observations fill the gap in the available data. To describe the variability of HD 50138 we have monitored this star spectroscopically over the last twenty years. To search for the periodicity on short-term scales, series of night-to-night observations were also obtained.
- ID:
- ivo://CDS.VizieR/J/ApJ/892/L35
- Title:
- He+He white dwarf SDSSJ232230.20+050942.0 RVels
- Short Name:
- J/ApJ/892/L35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a 1201s orbital period binary, the third shortest-period detached binary known. Sloan Digital Sky Survey J232230.20+050942.06 contains two He-core white dwarfs orbiting with a 27{deg} inclination. Located 0.76kpc from the Sun, the binary has an estimated Laser Interferometer Space Antenna (LISA) 4yr signal-to-noise ratio of 40. J2322+0509 is the first He+He white dwarf LISA verification binary, a source class that is predicted to account for one-third of resolved LISA ultra-compact binary detections.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/429
- Title:
- Herbig Ae/Be stars candidates
- Short Name:
- J/A+AS/136/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed 42 Herbig Ae/Be stars candidates in both hemispheres using the high resolution spectrographs AURELIE and ELODIE at OHP, and CES at ESO. Table 1 present the journal of our spectroscopic observations.
