2009/01/20 by Gavin Ramsay, Simon Rosen, Pasi Hakala +1 · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Binary number #Binary star #Eclipse #Emission spectrum #Light curve #Orbital elements #Orbital inclination #Stellar, planetary, and galactic studies #White dwarf #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.1111/j.1365-2966.2009.14528.x
Accepted for publication in MNRAS
arxiv created 2009/01/20 · openalex publication_date 2009/03/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report the discovery of an eclipsing polar, 2XMMi J225036.9+573154, using XMM–Newton. It was discovered by searching the light curves in the 2XMMi catalogue for objects showing X-ray variability. Its X-ray light curve shows a total eclipse of the white dwarf by the secondary star every 174 min. An extended pre-eclipse absorption dip is observed in soft X-rays at φ= 0.8–0.9, with evidence for a further dip in the soft X-ray light curve at φ∼ 0.4. Further, X-rays are seen from all orbital phases (apart from the eclipse) which make it unusual amongst eclipsing polars. We have identified the optical counterpart, which is faint (r= 21), and shows a deep eclipse (>3.5 mag in white light). Its X-ray spectrum does not show a distinct soft X-ray component which is seen in many, but not all, polars. Its optical spectrum shows Hα in emission for a fraction of the orbital period.