HS 0943+1404, a true intermediate polar
/ Authors
P. Rodríguez-Gil, B. Gaensicke, H. Hagen, D. Nogami, M. Torres, H. Lehto, A. Aungwerojwit, S. Littlefair, S. Araujo-Betancor, D. E. U. O. Warwick
and 15 more authors
UK., Instituto de Astrof'isica de Canarias, Iac, Spain., H. Sternwarte, H Germany, H. Observatory, Japan., H. C. F. Astrophysics, Usa, T. Observatory, Finland., U. Turku, U. Exeter, Space Telescope Science Institute
/ Abstract
We have identified a new intermediate polar, HS 0943+1404, as part of our ongoing search for cataclysmic variables in the Hamburg Quasar Survey. The orbital and white dwarf spin periods determined from time-resolved photometry and spectroscopy are P orb 250 min and P spin = 69.171 ± 0.001 min, respectively. The combination of a large ratio P spin /P orb 0.3 and a long orbital period is very unusual compared to the other known intermediate polars. The magnetic moment of the white dwarf is estimated to be µ 1 ∼ 10 34 Gcm 3, which is in the typical range of polars. Our extensive photometry shows that HS 0943+1404 enters into deep (∼3 mag) low states, which are also a characteristic feature of polars. We therefore suggest that the system is a true “intermediate” polar that will eventually synchronise, that is, a transitional object between intermediate polars and polars. The optical spectrum of HS 0943+1404 also exhibits a number of unusual emission lines, most noticeably N II λ5680, which is likely to reflect enhanced nitrogen abundances in the envelope of the secondary.
Journal: Astronomy and Astrophysics