The Nova Shell and Evolution of the Recurrent Nova T Pyxidis

Abstract

T Pyxidis is the prototypical recurrent nova (RN) with a mysterious nova shell. We report new observations of the shell with HST. The knots in the shell are expanding with velocities 500-715 km/s, for a distance of 3500 pc. The fractional expansion of the knots is constant, and this implies no significant deceleration. Hence, the knots were ejected by an eruption close to the year 1866. Knots have turned on after 1995, and this demonstrates that the knots are powered by shocks from the collision of the 1866 ejecta with fast ejecta from later RN eruptions. The 1866 ejecta has a total mass of 10^-4.5 Msun, which with the low ejection velocity shows that the 1866 event was an ordinary nova eruption, not a RN eruption. The accretion rate before the ordinary nova event must have been low (around the 4x10^-11 Msun/yr expected for gravitational radiation alone) and the matter accumulated on the surface of the white dwarf for ~750,000 years. The current accretion rate (>10^-8 Msun/yr) is 1000X higher than expected for a system below the period gap, with the plausible reason being that the 1866 event started a continuing supersoft source that drives the accretion. A key fact about T Pyx is that its accretion rate has been secularly declining since before the 1890 eruption, with the current rate being only 3% of its earlier rate. The decline in the observed accretion rate shows that the supersoft source is not self-sustaining, and we calculate that the accretion in T Pyx will effectively stop in upcoming decades. With this, T Pyx will enter a state of hibernation, lasting for an estimated 2,600,000 years, before gravitational radiation brings the system into contact again. Thus, T Pyx has an evolutionary cycle going from an ordinary CV state, to its current RN state, to a future hibernation state, and then repeating this cycle.

Astrophysical Journal in press, 62 pages, 11 figures (accepted version; minor changes and shortening)

References in corpus (7)

• A Universal Decline Law of Classical Novae
• The space density of cataclysmic variables: constraints from the ROSAT North Ecliptic Pole Survey
• The Delay Time Distribution of Type Ia Supernovae and the Single Degenerate Model
• The Behavior of Novae Light Curves Before Eruption
• The secrets of T Pyxidis II. A recurrent nova that will not become a SN Ia
• Swift X-ray and UV monitoring of the Classical Nova V458 Vul (Nova Vul 2007)
• Modeling the Galactic CV Distribution for the ChaMPlane Survey

Cited by in corpus (42)

• Observational clues to the progenitors of Type-Ia supernovae
• Comprehensive Photometric Histories of All Known Galactic Recurrent Novae
• Identifying and Quantifying Recurrent Novae Masquerading as Classical Novae
• The Progenitor of the Type Ia Supernova that created SNR 0519-69.0 in the Large Magellanic Cloud
• White Dwarf/M Dwarf Binaries as Single Degenerate Progenitors of Type Ia Supernovae
• The orbital period and system parameters of the recurrent nova T Pyx
• The 2011 outburst of the recurrent novaT Pyx. Evidence for a face-on bipolar ejection
• The 2011 Outburst of Recurrent Nova T Pyx: X-ray Observations Expose the White Dwarf Mass and Ejection Dynamics
• The spectroscopic evolution of the recurrent nova T Pyxidis during its 2011 outburst. II.The optically thin phase and the structure of the ejecta in recurrent novae
• The 2011 Outburst of Recurrent Nova T Pyx: Radio Observations Reveal the Ejecta Mass and Hint at Complex Mass Loss
• Novae With Long-Lasting Supersoft Emission That Drive a High Accretion Rate
• The Radio Light Curve of the Gamma-Ray Nova in V407 Cyg: Thermal Emission from the Ionized Symbiotic Envelope, Devoured from Within by the Nova Blast
• The Change of the Orbital Periods Across Eruptions and the Ejected Mass For Recurrent Novae CI Aquilae and U Scorpii
• X-Ray Grating Observations of Recurrent Nova T Pyxidis During The 2011 Outburst
• The Inter-Eruption Timescale of Classical Novae from Expansion of the Z Camelopardalis Shell
• The Recurrent Nova T Pyx: Distance and Remnant Geometry from Light Echoes
• GK Per (Nova Persei 1901): HST Imagery and Spectroscopy of the Ejecta, and First Spectrum of the Jet-Like Feature
• Novae heat their food: mass transfer by irradiation
• The luminosity evolution of nova shells -- I. A new analysis of old data
• T Pyxidis: Death by a Thousand Novae
• The Detailed Photometric and Spectroscopic Study of the 2011 Outburst of the Recurrent Nova T Pyxidis from 0.8 to 250 Days after Discovery
• Optical spectroscopic and polarization properties of 2011 outburst of the recurrent nova T Pyxidis
• A Triple Star Origin For T Pyx and Other Short-Period Recurrent Novae
• The structure of a recent nova shell as observed by ALMA
• Dynamical Fragmentation of the T Pyxidis Nova Shell During Recurrent Eruptions
• Introducing the Condor Array Telescope: IV. A possible nova super-remnant surrounding the putative recurrent nova KT Eridani
• SALT observations of southern post-novae
• HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis
• Non-Equipartition of Energy, Masses of Nova Ejecta, and Type Ia Supernovae
• Hubble Space Telescope Far Ultraviolet Spectroscopy of the Recurrent Nova T Pyxidis
• The Long-Term Secular Mass Accretion Rate of the Recurrent Nova T Pyxidis
• Cataclysmic variables as possible counterparts of ancient Far Eastern guest stars
• Photometry of the Stingray Nebula (V839 Ara) from 1889-2015 Across the Ionization of Its Planetary Nebula
• Infrared observations of the recurrent nova T Pyxidis: ancient dust basks in the warm glow of the 2011 outburst
• Orbital Period Changes for Fourteen Novae and the Critical Failures of the Predictions of Standard Theories, the Hibernation Model, and the Magnetic Braking Model
• Counterparts of Far Eastern Guest Stars: Novae, supernovae, or something else?
• A Search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE, and 393 CE
• The XMM-Newton Detection of Extended Emission from the Nova Remnant of T Pyxidis
• Supersoft X-Ray Phases of Recurrent Novae as an Indicator of their White Dwarf Masses
• Pre-outburst $Chandra$ Observations of the Recurrent Nova T Pyxidis
• The slow decline of the Galactic recurrent novae T Pyxidis, IM Normae, and CI Aquilae
• Review of light curves of novae in the modified scales. I. Recurrent novae