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1001. HD54662 radial velocities and X-ray light curves
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.
1002. HD 261711 reduced spectrum
ID:
ivo://CDS.VizieR/J/A+A/552/A68
Title:
HD 261711 reduced spectrum
Short Name:
J/A+A/552/A68
Date:
21 Oct 2021
Publisher:
CDS
Description:
The internal structure of pre-main-sequence (PMS) stars is poorly constrained at present. This could change significantly through high-quality asteroseismological observations of a sample of such stars. We concentrate on an asteroseismological study of HD 261711, a rather hot delta Scuti-type pulsating member of the young open cluster NGC 2264 located at the blue border of the instability region. HD 261711 was discovered to be a pre-main sequence delta Scuti star using the time series photometry obtained by the MOST satellite in 2006. High-precision, time-series photometry of HD 261711 was obtained by the MOST and CoRoT satellites in four separate new observing runs that are put into context with the star's fundamental atmospheric parameters obtained from spectroscopy. Frequency Analysis was performed using Period04. The spectral analysis was performed using equivalent widths and spectral synthesis. With the new MOST data set from 2011/12 and the two CoRoT light curves from 2008 and 2011/12, the delta Scuti variability was confirmed and regular groups of frequencies were discovered. The two pulsation frequencies identified in the data from the first MOST observing run in 2006 are confirmed and 23 new delta Scuti-type frequencies were discovered using the CoRoT data. Weighted average frequencies for each group were determined and are related to l=0 and l=1 p-modes. Evidence for amplitude modulation of the frequencies in two groups is seen. The effective temperature (Teff) was derived to be 8600+/-200K, logg is 4.1+/-0.2, and the projected rotational velocity (vsini) is 53+/-1km/s. Using our Teff value and the radius of 1.8+/-0.5R_{sun}_ derived from spectral energy distribution (SED) fitting, we get a luminosity logL/L_{sun}_ of 1.20+/-0.14 which agrees well to the seismologically determined values of 1.65 Rsun and, hence, a logL/L_{sun}_ of 1.13. The radial velocity of 14+/-2km/s we derived for HD 261711, confirms the star's membership to NGC 2264. Our asteroseismic models suggest that HD 261711 is a delta Scuti-type star close to the zero-age main sequence (ZAMS) with a mass of 1.8 to 1.9M_{sun}_. With an age of about 10 million years derived from asteroseismology, the star is either a young ZAMS star or a late PMS star just before the onset of hydrogen-core burning. The observed splittings about the l=0 and 1 parent modes may be an artifact of the Fourier derived spectrum of frequencies with varying amplitudes.
1003. HD 50138 short-term variability
ID:
ivo://CDS.VizieR/J/A+A/548/A13
Title:
HD 50138 short-term variability
Short Name:
J/A+A/548/A13
Date:
21 Oct 2021
Publisher:
CDS
Description:
HD 50138 presents the B[e] phenomenon, but its nature is not clear yet. This star is known to present spectral variations, which have been associated with outbursts and shell phases. We analyze the line profile variability of HD 50138 and its possible origin, which provide possible hints to its evolutionary stage, so far said to be close to the end of (or slightly beyond) the main sequence.
1004. HD199178 1994-2017 spectra
ID:
ivo://CDS.VizieR/J/A+A/625/A79
Title:
HD199178 1994-2017 spectra
Short Name:
J/A+A/625/A79
Date:
21 Oct 2021
Publisher:
CDS
Description:
High-resolution spectral observations during 1994-2017 are analysed in order to reveal long- and short-term changes in the spot activity of the FK Comae-type subgiant HD 199178. Most of the observations were collected with the Nordic Optical Telescope high resolution spectrographs SOFIN (34 sets) and FIES (6 sets). One set was obtained at the NAO (Rozhen), Bulgaria. The spectra were used to calculate Doppler imaging temperature maps for HD 199178 covering the years 1994-2017.
1005. HD 192163 spectroscopic study
ID:
ivo://CDS.VizieR/J/AZh/88/380
Title:
HD 192163 spectroscopic study
Short Name:
J/AZh/88/380
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used 46 high-resolution echelle spectra of the Wolf-Rayet star HD 192163 taken in 2005-2009 at the Cassegrain focus of the 2-m Zeiss-2000 telescope of the Shamakha Astrophysical Observatory to study profiles of the five strongest emission lines (HeII 4859, HeII 5411, CIV 5808, HeI 5875, (HeII+Halpha) 6560). We also obtained four echelle spectrograms of the Wolf-Rayet star HD 191765 for a comparative study of the NaI 5890 (D2) and NaI 5896 (D1) interstellar absorption lines. The echelle spectrograms were reduced using the DECH20 code. We determined the equivalent widths, radial velocities, central intensities, and half-widths of the emission lines. We We also studied the NaI 5890 (D2) and NaI 5896 (D1) interstellar absorption lines, which are important for understanding the nature of the nebula NGC 6888, whose origin is related to HD 192163.
1006. HD 46703 spectroscopy and photometry
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.
1007. HD 284149 SPHERE/IFS spectrum
ID:
ivo://CDS.VizieR/J/A+A/608/A106
Title:
HD 284149 SPHERE/IFS spectrum
Short Name:
J/A+A/608/A106
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present the results of the SPHERE observation of the HD 284149 system, aimed at a more detailed characterisation of both the primary and its brown dwarf companion. We observed HD 284149 in the near-infrared with SPHERE, using the imaging mode (IRDIS+IFS) and the long-slit spectroscopy mode (IRDIS-LSS). The data were reduced using the dedicated SPHERE pipeline, and algorithms such as PCA and TLOCI were applied to reduce the speckle pattern. The IFS images revealed a previously unknown low-mass (~0.16M_{sun}_) stellar companion (HD 294149 B) at ~0.1", compatible with previously observed radial velocity differences, as well as proper motion differences between Gaia and Tycho-2 measurements. The known brown dwarf companion (HD 284149 b) is clearly visible in the IRDIS images. This allowed us to refine both its photometry and astrometry. The analysis of the medium resolution IRDIS long slit spectra also allowed a refinement of temperature and spectral type estimates. A full reassessment of the age and distance of the system was also performed, leading to more precise values of both mass and semi-major axis. As a result of this study, HD 284149 ABb therefore becomes the latest addition to the (short) list of brown dwarfs on wide circumbinary orbits, providing new evidence to support recent claims that object in such configuration occur with a similar frequency to wide companions to single stars.
1008. HDS spectrum of nova V2659 Cyg (Nova Cyg 2014)
ID:
ivo://CDS.VizieR/J/ApJ/830/30
Title:
HDS spectrum of nova V2659 Cyg (Nova Cyg 2014)
Short Name:
J/ApJ/830/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on high-dispersion spectroscopy results of a classical nova V2659 Cyg (Nova Cyg 2014) that are taken 33.05 days after the V-band maximum. The spectrum shows two distinct blueshifted absorption systems originating from H I, Fe II, Ca II, etc. The radial velocities of the absorption systems are -620km/s, and -1100 to -1500km/s. The higher velocity component corresponds to the P-Cygni absorption features frequently observed in low-resolution spectra. Much larger numbers of absorption lines are identified at the lower velocity. These mainly originate from neutral or singly ionized Fe-peak elements (Fe I, Ti II, Cr II, etc.). Based on the results of our spectroscopic observations, we discuss the structure of the ejecta of V2659 Cyg. We conclude that the low- and high-velocity components are likely to be produced by the outflow wind and the ballistic nova ejecta, respectively.
1009. HD50138 time-dependent spectral variations
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.
1010. HD 88133 11-yrs radial velocity measurements
ID:
ivo://CDS.VizieR/J/ApJ/832/131
Title:
HD 88133 11-yrs radial velocity measurements
Short Name:
J/ApJ/832/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L-band observations and three epochs of Keck NIRSPEC K-band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross-correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40+/-15km/s, a true mass of 1.02_-0.28_^+0.61^M_J_, a nearly face-on orbital inclination of 15_-5_^+6^{deg}, and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with 11 years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

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