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J/A+A/615/A131      R CMa radial velocity curves                (Lehmann+, 2018)

Spectroscopic time-series analysis of R Canis Majoris. Lehmann H., Tsymbal V., Pertermann A., Tkachenko A., Mkrtichian D.E., A-thano N. <Astron. Astrophys. 615, A131 (2018)> =2018A&A...615A.131L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Binaries, eclipsing ; Binaries, spectroscopic; Radial velocities Keywords: binaries: eclipsing - binaries: spectroscopic - stars: oscillations - stars: variables: delta Scuti Abstract: R Canis Majoris is the prototype of a small group of Algol-type stars showing short orbital periods and low mass ratios. A previous detection of short-term oscillations in its light curve has not yet been confirmed. We investigate a new time series of high-resolution spectra with the aim to derive improved stellar and system parameters, to search for the possible impact of a third component in the observed spectra, to look for indications of activity in the Algol system, and to search for short-term variations in radial velocities. We disentangled the composite spectra into the spectra of the binary components. Then we analysed the resulting high signal-to-noise spectra of both stars. Using a newly developed program code based on an improved method of least-squares deconvolution, we were able to determine the radial velocities of both components also during primary eclipse. This allowed us to develop a better model of the system including the Rossiter-McLaughlin effect and to derive improved orbital parameters. Combining the results with those from spectrum analysis, we obtain accurate stellar and system parameters. We further deduce at least one oscillation frequency of 21.38c/d. It could be detected during primary eclipses only and confirms a previous photometric finding. Results point to an amplitude amplification of non-radial pulsation modes due to the eclipse mapping effect. The presence of a HeI line in the spectra indicates mass transfer in the R CMa system. Calculations of its Roche geometry give evidence that the cool secondary component may fill its Roche lobe. No evidence of a third body in the system could be found in the observed spectra. Description: A time series of radial velocities of the hot (RV1) and cool (RV2) components of the eclipsing binary star R CMa is presented, derived with the new least- squares-deconvolution code LSDbinary from a time series of high-resolution spectra taken with the HERMES spectrograph attached to the Mercator telescope at La Palma. Objects: -------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------- 07 19 28.18 -16 23 42.9 R CMa = HD 57167 -------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 29 560 Radial velocities of R CMa
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 11 F11.7 --- BJD Barycentric Julian date (BJD-2457000) 13- 20 F8.3 km/s RV1 Radial velocity of the primary component (1) 22- 29 F8.3 km/s RV2 Radial velocity of the secondary component (1)
Note (1): The primary is the brighter, hot component and the secondary component is the cool companion in the Algol-type system.
Acknowledgements: Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The HERMES spectrograph is supported by the Research Foundation - Flanders (FWO), Belgium; the Research Council of KU Leuven, Belgium; the Fonds National de la Recherche Scientifique (F.R.S.-FNRS), Belgium; the Royal Observatory of Belgium; the Observatoire de Geneve, Switzerland; and the Thueringer Landessternwarte Tautenburg, Germany. Holger Lehmann, lehm(at)tls-tautenburg.de
(End) Holger Lehmann [TLS, Germany], Patricia Vannier [CDS] 18-Apr-2018
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