Post common envelope binaries from the SDSS VI. SDSS J120615.73+510047.0: a new low accretion rate magnetic binary

作者：Schwope A D^*; Gomez Moran A Nebot; Schreiber M R; Gaensicke B T

来源：Astronomy & Astrophysics, 2009, 500(2): 867-872.

DOI：10.1051/0004-6361/200911699

• accretion, accretion disks
• stars: magnetic fields
• binaries: close
• stars: individual: SDSS J120615.73+510047.0

We report the discovery of the ninth pre-polar consisting of a late-type ZAMS secondary and a magnetic white dwarf. The white dwarf accretes at an extreme low rate,. (M) over dot similar to 10(-14) M(circle dot) yr(-1), from the wind of the companion donor star. The source was found in our systematic search for WD/MS binaries within SDSS/SEGUE. Based on seven Sloan spectra we estimate a binary period of similar to 200, 230, or 270 min. The UV to IR spectral energy distribution was decomposed into a dM3-dM4 ZAMS secondary and a cool white dwarf, similar to 9000 K, which consistently imply a distance between 360 and 420 pc. The optical spectrum displays one pronounced cyclotron hump, likely originating from a low-temperature plasma, similar to 1 keV, in a field of 108 MG. We comment on the evolutionary link between polars and pre-polars.

• 出版日期2009-6