Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996mnras.278..565m&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Volume 278, Issue 2, pp. 565-576.
Astronomy and Astrophysics
Astronomy
25
Binaries: Close, Binaries: Spectroscopic, Stars: Individual: Gd 448, Stars: Low-Mass, Brown Dwarfs, Novae, Cataclysmic Variables, White Dwarfs
Scientific paper
We find that the white dwarf GD 448 is a detached white dwarf/M dwarf binary with an orbital period of 2.47h. This is the shortest period known for such a binary, placing it in the centre of the `period gap' from 2 to 3h in which few cataclysmic variable stars (mass-transferring white dwarf/main-sequence star systems) are found. The cooling age of the white dwarf (5x10^7 yr) shows that GD 448 was born in the gap and has never been a cataclysmic variable star. We measure radial velocity semi-amplitudes of K_W=31.2+/-1.5 km s^-1 and K_E=122.2+/-1.1 km s^-1 from Hα absorption from the white dwarf and Hα and CaII triplet emission from the M star. The white dwarf absorption shows a gravitational redshift of 16.8+/-1.6 km s^-1, leading to a mass of 0.44+/-0.03 M_solar for the white dwarf. The Hα and CaII emission-line fluxes are modulated by a factor of 4, and are strongest when the M dwarf is furthest from us. The flux variation is consistent with emission proportional to the irradiating flux from the white dwarf, and yet the latter is not hot enough to have produced the emission by photoionization alone. The asymmetric distribution means that K_E is less than the true K velocity of the M star, K_M. From models of the emission we find that 138
Duck S. R.
Marsh Thomas R.
No associations
LandOfFree
A detached white dwarf/M dwarf binary with an orbital period of 2.47h does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A detached white dwarf/M dwarf binary with an orbital period of 2.47h, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A detached white dwarf/M dwarf binary with an orbital period of 2.47h will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1126467