CI Aql: a Type Ia supernova progenitor?

Abstract

If recurrent novae are progenitors of Type Ia supernovae, their white dwarfs must have masses close to the Chandrasekhar limit. The most reliable means of determining white dwarf masses in recurrent novae is dynamically, via radial-velocity and rotational-broadening measurements of the companion star. Such measurements require the system to be both eclipsing and to show absorption features from the secondary star. Prior to the work reported here, the only dynamical mass estimate of a recurrent nova was for U Sco, which has a white dwarf mass of 1.55 +/- 0.24 Msolar (Thoroughgood et al. 2001). We present new time-resolved, intermediate-resolution spectroscopy of the eclipsing recurrent nova CI Aquilae (CI Aql) during quiescence. We find the mass of the white dwarf to be 1.00 +/- 0.14 Msolar and the mass of the secondary star to be 2.32 +/- 0.19 Msolar. We estimate the radius of the secondary to be 2.07 +/- 0.06 Rsolar, implying that it is a slightly-evolved early A-type star. The high mass ratio of q = 2.35 +/- 0.24 and the high secondary-star mass implies that the mass transfer occurs on a thermal timescale. We suggest that CI Aql is rapidly evolving into a supersoft X-ray source, and ultimately may explode as a Type Ia supernova within 10 Myr.

Accepted for publication in MNRAS 2013 May 9. 12 Figures, 3 Tables, 12 Pages

References in corpus (13)

• Supernova 2011fe from an Exploding Carbon-Oxygen White Dwarf Star
• Type-Ia supernova rates and the progenitor problem, a review
• A Compact Degenerate Primary-Star Progenitor of SN 2011fe
• The Long-Term Evolution of Double White Dwarf Mergers
• Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra
• Variable Sodium Absorption in a Low-Extinction Type Ia Supernova
• 2D simulations of the double-detonation model for thermonuclear transients from low-mass carbon-oxygen white dwarfs
• Early radio and X-ray observations of the youngest nearby type Ia supernova PTF11kly (SN 2011fe)
• Young and Massive Binary Progenitors of Type Ia Supernovae and Their Circumstellar Matter
• A Swift Look at SN 2011fe: The Earliest Ultraviolet Observations of a Type Ia Supernova
• The Merger Rate of Binary White Dwarfs in the Galactic Disk
• The Delay Time Distribution of Type Ia Supernovae and the Single Degenerate Model
• The Change of the Orbital Periods Across Eruptions and the Ejected Mass For Recurrent Novae CI Aquilae and U Scorpii

Cited by in corpus (11)

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• On the Progenitors of Type Ia Supernovae
• Growing White Dwarfs to the Chandrasekhar Limit: The Parameter Space of the Single Degenerate SNIa Channel
• The Masses and Accretion Rates of White Dwarfs in Classical and Recurrent Novae
• New approaches to SNe Ia progenitors
• A common-envelope wind model for Type Ia supernovae (I): binary evolution and birth rate
• A Catalogue of Potential Post Common Envelope Binaries
• The UBV Color Evolution of Classical Novae. II. Color-Magnitude Diagram
• Shortest Recurrence Periods of Forced Novae
• HST FUV spectroscopy of the short orbital period recurrent nova CI Aql: Implications for white dwarf mass evolution
• Coaxing the Eclipsing Binary V367 Cygni Out of Its Shell