The 2011 outburst of recurrent nova T Pyx: X-ray observations expose the white dwarf mass and ejection dynamics
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
- School of Physics and Astronomy, University of Minnesota, 115 Church Street SE, Minneapolis, MN 55455 (United States)
- CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States)
- Columbia Astrophysics Laboratory, Columbia University, New York, NY (United States)
- National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
- Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom)
- European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Caada, Madrid (Spain)
- Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)
The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and became the subject of an intensive multi-wavelength observational campaign. We analyze data from the Swift and Suzaku satellites to produce a detailed X-ray light curve augmented by epochs of spectral information. X-ray observations yield mostly non-detections in the first four months of outburst, but both a super-soft and hard X-ray component rise rapidly after Day 115. The super-soft X-ray component, attributable to the photosphere of the nuclear-burning white dwarf, is relatively cool (∼45 eV) and implies that the white dwarf in T Pyx is significantly below the Chandrasekhar mass (∼1 M {sub ☉}). The late turn-on time of the super-soft component yields a large nova ejecta mass (≳ 10{sup –5} M {sub ☉}), consistent with estimates at other wavelengths. The hard X-ray component is well fit by a ∼1 keV thermal plasma, and is attributed to shocks internal to the 2011 nova ejecta. The presence of a strong oxygen line in this thermal plasma on Day 194 requires a significantly super-solar abundance of oxygen and implies that the ejecta are polluted by white dwarf material. The X-ray light curve can be explained by a dual-phase ejection, with a significant delay between the first and second ejection phases, and the second ejection finally released two months after outburst. A delayed ejection is consistent with optical and radio observations of T Pyx, but the physical mechanism producing such a delay remains a mystery.
- OSTI ID:
- 22356602
- Journal Information:
- Astrophysical Journal, Vol. 788, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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