Open AccessRotational period of WD 1953 – 011 – a magnetic white dwarf with a star‐spot
Author(s) -
Brinkworth C. S.,
Marsh T. R.,
MoralesRueda L.,
Maxted P. F. L.,
Burleigh M. R.,
Good S. A.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.08649.x
Subject(s) - physics , white dwarf , astrophysics , balmer series , photometry (optics) , amplitude , starspot , rotation period , sunspot , astronomy , magnetic field , light curve , spectral line , stars , optics , emission spectrum , quantum mechanics
WD 1953–011 is an isolated, cool (7920 ± 200 K) magnetic white dwarf (MWD) with a low average field strength (∼70 kG), and a higher than average mass (∼0.74 M ⊙ ) . Spectroscopic observations taken by Maxted et al. showed variations of equivalent width in the Balmer lines, unusual in a low‐field white dwarf. Here we present V ‐band photometry of WD 1953–011 taken at seven epochs over a total of 22 months. All of the data sets show a sinusoidal variation of approximately 2 per cent peak‐to‐peak amplitude. We propose that these variations are due to a star‐spot on the MWD, analogous to a sunspot, which is affecting the temperature at the surface, and therefore its photometric magnitude. The variations have a best‐fitting period over the entire 22 months of 1.4418 d, which we interpret as the rotational period of the white dwarf.