TY - JOUR
T1 - Hubble space telescope far ultraviolet spectroscopy of the recurrent nova t pyxidis
AU - Godon, Patrick
AU - Sion, Edward M.
AU - Starrfield, Sumner
AU - Livio, Mario
AU - Williams, Robert E.
AU - Woodward, Charles E.
AU - Kuin, Paul
AU - Page, Kim L.
PY - 2014/4/1
Y1 - 2014/4/1
N2 - With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few ∼10-5 M to 3.3 × 10-4 M, and assuming a mass accretion rate of 10-8-10 -7 M yr-1 for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B-V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ E(B-V) ≤ 0.50) and white dwarf mass (0.70 M · ≤ M wd ≤ 1.35 M ·) the accreted mass is larger than the ejected mass. Only for a low reddening (∼0.25 and smaller) combined with a large white dwarf mass (0.9 M and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.
AB - With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few ∼10-5 M to 3.3 × 10-4 M, and assuming a mass accretion rate of 10-8-10 -7 M yr-1 for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B-V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ≤ E(B-V) ≤ 0.50) and white dwarf mass (0.70 M · ≤ M wd ≤ 1.35 M ·) the accreted mass is larger than the ejected mass. Only for a low reddening (∼0.25 and smaller) combined with a large white dwarf mass (0.9 M and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.
KW - accretion accretion disks
KW - binaries: close
KW - novae cataclysmic variables
KW - stars: individual (T Pyxidis)
KW - ultraviolet: stars
KW - white dwarfs
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U2 - 10.1088/2041-8205/784/2/L33
DO - 10.1088/2041-8205/784/2/L33
M3 - Article
AN - SCOPUS:84896967733
SN - 2041-8205
VL - 784
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L33
ER -