Novae heat their food: Mass transfer by irradiation

Sivan Ginzburg*, Eliot Quataert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

A nova eruption irradiates and heats the donor star in a cataclysmic variable to high temperatures Tirr, causing its outer layers to expand and overflow the Roche lobe. We calculate the donor's heating and expansion both analytically and numerically, under the assumption of spherical symmetry, and find that irradiation drives enhanced mass transfer from the donor at a rate m ∝ Tirr5/3, which reaches m ∼ 10-6 M⊙ yr-1 at the peak of the eruption - about a thousand times faster than during quiescence. As the nova subsides and the white dwarf cools down, m drops to lower values. We find that under certain circumstances, the decline halts and the mass transfer persists at a self-sustaining rate of m∼ 10-7 M⊙ yr-1 for up to ∼103 yr after the eruption. At this rate, irradiation by the white dwarf's accretion luminosity is sufficient to drive the mass transfer on its own. The self-sustaining rate is close to the white dwarf's stable burning limit, such that this bootstrapping mechanism can simultaneously explain two classes of puzzling binary systems: recurrent novae with orbital periods ≈2 h (T Pyxidis and IM Normae) and long-lived supersoft X-ray sources with periods ≈4 h (RX J0537.7-7034 and 1E 0035.4-7230). Whether or not a system reaches the self-sustaining state is sensitive to the donor's chromosphere structure, as well as to the orbital period change during nova eruptions.

Original languageEnglish
Pages (from-to)475-483
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume507
Issue number1
DOIs
StatePublished - 1 Oct 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.

Keywords

  • binaries: close
  • novae, cataclysmic variables
  • stars: individual: IM Normae
  • stars: individual: T Pyxidis

Fingerprint

Dive into the research topics of 'Novae heat their food: Mass transfer by irradiation'. Together they form a unique fingerprint.

Cite this