HUBBLE SPACE TELESCOPE FAR ULTRAVIOLET SPECTROSCOPY OF THE RECURRENT NOVA T PYXIDIS

Area of Science:

• Astrophysics
• Stellar Evolution
• Cataclysmic Variables

Background:

• T Pyxidis (T Pyx) is a prototypical recurrent nova, crucial for understanding white dwarf mass changes.
• Previous studies suggested T Pyx's white dwarf loses mass based on ejected mass estimates and assumed accretion rates.

Purpose of the Study:

• To reassess the net mass change of the white dwarf in T Pyx.
• To determine accurate mass accretion rates using advanced modeling and new observational data.

Main Methods:

• Utilized Hubble Space Telescope (HST) COS and STIS spectra.
• Applied Non-Local Thermodynamic Equilibrium (NLTE) disk modeling for spectral analysis.
• Incorporated updated distance and reddening values for T Pyx.

Main Results:

• Derived a mass accretion rate up to two orders of magnitude higher than previously estimated.
• New distance (4.8 kpc) and reddening (E(B-V) = 0.35) significantly impact accretion calculations.
• Accreted mass generally exceeds ejected mass for T Pyx within typical parameter ranges.

Conclusions:

• The white dwarf in T Pyx is likely accreting mass, not losing it.
• Accurate distance, reddening, and NLTE modeling are critical for understanding nova system evolution.
• Further investigation is needed for scenarios where ejected mass might exceed accreted mass (low reddening, high white dwarf mass).