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arXiv · 2001.07288

The Spin-Period History of Intermediate Polars

Joseph Patterson·Enrique de Miguel·Jonathan Kemp·Shawn Dvorak·Berto Monard·Franz-Josef Hambsch·Tonny Vanmunster·David R. Skillman·David Cejudo·Tut Campbell·George Roberts·Jim Jones·Lewis M. Cook·Greg Bolt·Robert Rea·Joseph Ulowetz·Thomas Krajci·Kenneth Menzies·Simon Lowther·William Goff·William Stein·Matt A. Wood·Gordon Myers·Geoffrey Stone·Helena Uthas·Emir Karamehmetoglu·Jim Seargeant·Jennie McCormick
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Abstract

We report the detailed history of spin-period changes in five intermediate polars (DQ Herculis, AO Piscium, FO Aquarii, V1223 Sagittarii, and BG Canis Minoris) during the 30-60 years since their original discovery. Most are slowly spinning up, although there are sometimes years-long episodes of spin-down. This is supportive of the idea that the underlying magnetic white dwarfs are near spin equilibrium. In addition to the ~40 stars sharing many properties and defined by their strong, pulsed X-ray emission, there are a few rotating much faster (P<80 s), whose membership in the class is still in doubt -- and who are overdue for closer study.

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Joseph Patterson, Enrique de Miguel, Jonathan Kemp, Shawn Dvorak, Berto Monard, Franz-Josef Hambsch, Tonny Vanmunster, David R. Skillman, David Cejudo, Tut Campbell, George Roberts, Jim Jones, Lewis M. Cook, Greg Bolt, Robert Rea, Joseph Ulowetz, Thomas Krajci, Kenneth Menzies, Simon Lowther, William Goff, William Stein, Matt A. Wood, Gordon Myers, Geoffrey Stone, Helena Uthas, Emir Karamehmetoglu, Jim Seargeant, Jennie McCormick. 2020-01-20. The Spin-Period History of Intermediate Polars. https://doi.org/10.3847/1538-4357/ab863d

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