An extended grid of nova models. III. Very luminous, red novae

Michael M. Shara, Ofer Yaron, Dina Prialnik, Attay Kovetz, David Zurek

Research output: Contribution to journalArticlepeer-review

Abstract

Extremely luminous, red eruptive variables like RV in M31 are being suggested as exemplars of a new class of astrophysical objects. Our greatly extended series of nova simulations shows that classical nova models can produce very red, luminous eruptions. In a poorly studied corner of three-dimensional nova parameter space (very cold, low-mass white dwarfs, accreting at very low rates) we find bona fide classical novae that are very luminous and red because they eject very slowly moving, massive envelopes. A crucial prediction of these nova models-in contrast to the predictions of merging star (" mergeburst") models-is that a hot remnant, the underlying white dwarf, will emerge after the massive ejected envelope has expanded enough to become optically thin. This blue remnant must fade on a timescale of decades-much faster than a "mergeburst," which must fade on timescales of millennia or longer. Furthermore, the cooling nova white dwarf and its expanding ejecta must become redder in the years after eruption, while a contracting mergeburst must become hotter and bluer. We predict that red novae will always brighten to L∼1000 Lfor about one year before rising to the maximum luminosity at L∼106-107 L. The maximum luminosity attainable by a nova is likely to be L∼107 L , corresponding to M∼-12. In an accompanying paper, we describe a fading, luminous blue candidate for the remnant of M31-RV; it is observed with the Hubble Space Telescope to be compatible only with the nova model.

Original languageEnglish
Pages (from-to)831-841
Number of pages11
JournalAstrophysical Journal
Volume725
Issue number1
DOIs
StatePublished - 10 Dec 2010

Keywords

  • Accretion
  • Accretion disks
  • Binaries: close
  • Cataclysmic variables
  • Novae
  • White dwarfs

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