TY - JOUR
T1 - The 2011 outburst of recurrent nova T Pyx
T2 - X-ray observations expose the white dwarf mass and ejection dynamics
AU - Chomiuk, Laura
AU - Nelson, Thomas
AU - Mukai, Koji
AU - Sokoloski, J. L.
AU - Rupen, Michael P.
AU - Page, Kim L.
AU - Osborne, Julian P.
AU - Kuulkers, Erik
AU - Mioduszewski, Amy J.
AU - Roy, Nirupam
AU - Weston, Jennifer
AU - Krauss, Miriam I.
PY - 2014/6/20
Y1 - 2014/6/20
N2 - 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). The late turn-on time of the super-soft component yields a large nova ejecta mass (≳ 10 -5 M), 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.
AB - 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). The late turn-on time of the super-soft component yields a large nova ejecta mass (≳ 10 -5 M), 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.
KW - X-rays: stars
KW - novae, cataclysmic variables
KW - stars: individual (T Pyxidis)
KW - white dwarfs
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U2 - 10.1088/0004-637X/788/2/130
DO - 10.1088/0004-637X/788/2/130
M3 - Article
AN - SCOPUS:84902207042
SN - 0004-637X
VL - 788
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 130
ER -