DE Canum Venaticorum : a bright, eclipsing red dwarf–white dwarf binary
Besselaar, E. J. M. van den, Greimel, R., Morales-Rueda, L., Nelemans, G., Thorstensen, John Robert, Marsh, T. R., Dhillon, V. S., Robb, R. M. (Russell M.), Balam, D. D., Guenther, Eike W., Kemp, J. (Jonathan), Augusteijn, T. and Groot, P. J. (Paul J.). (2007) DE Canum Venaticorum : a bright, eclipsing red dwarf–white dwarf binary. Astronomy & Astrophysics, Vol.466 (No.3). pp. 1031-1041. ISSN 0004-6361
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Official URL: http://dx.doi.org/10.1051/0004-6361:20066246
Context. Close white dwarf–red dwarf binaries must have gone through a common-envelope phase during their evolution. DE CVn is a detached white dwarf–red dwarf binary with a relatively short (∼8.7 h) orbital period. Its brightness and the presence of eclipses makes this system ideal for a more detailed study.
Aims. From a study of photometric and spectroscopic observations of DE CVn we derive the system parameters that we discuss in the framework of common-envelope evolution.
Methods. Photometric observations of the eclipses are used to determine an accurate ephemeris. From a model fit to an average lowresolution spectrum of DE CVn, we constrain the temperature of the white dwarf and the spectral type of the red dwarf. The eclipse light curve is analysed and combined with the radial velocity curve of the red dwarf determined from time-resolved spectroscopy to derive constraints on the inclination and the masses of the components in the system.
Results. The derived ephemeris is HJDmin = 2 452 784.5533(1) + 0.3641394(2) × E. The red dwarf in DE CVn has a spectral type of M3V and the white dwarf has an effective temperature of 8 000 K. The inclination of the system is 86+3◦ −2 and the mass and radius of the red dwarf are 0.41 ± 0.06 M and 0.37+0.06 −0.007 R, respectively, and the mass and radius of the white dwarf are 0.51+0.06
−0.02 M and 0.0136+0.0008 −0.0002 R, respectively.
Conclusions. We found that the white dwarf has a hydrogen-rich atmosphere (DA-type). Given that DE CVn has experienced a common-envelope phase, we can reconstruct its evolution and we find that the progenitor of the white dwarf was a relatively lowmass star (M ≤ 1.6 M). The current age of this system is 3.3−7.3 × 109 years, while it will take longer than the Hubble time for DE CVn to evolve into a semi-detached system.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Eclipsing binaries, Double stars -- Evolution, Red dwarf stars, White dwarf stars|
|Journal or Publication Title:||Astronomy & Astrophysics|
|Official Date:||May 2007|
|Page Range:||pp. 1031-1041|
|Access rights to Published version:||Open Access|
|Funder:||Nederlandse Organisatie voor Wetenschappelijk Onderzoek [Netherlands Organisation for Scientific Research] (NWO), National Science Foundation (U.S.) (NSF), Particle Physics and Astronomy Research Council (Great Britain) (PPARC), Instituto de Astrofísica de Canarias|
|Grant number:||639.042.201 (NWO), 638.041.405 (NWO), AST-9987334 (NSF), AST-0307413 (NSF), PP/D002370/1 (PPARC), PPA/G/S/2003/00058 (PPARC)|
Bergeron, P.,Wesemael, F., & Fontaine, G. 1991, ApJ, 367, 253
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