Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae

Raddi R, Hollands MA, Koester D, Hermes JJ, Gansicke BT, Heber U, Shen KJ, Townsley DM, Pala AF, Reding JS, Toloza OF, Pelisoli I, Geier S, Fusillo NPG, Munari U, Strader J (2019)

Publication Type: Journal article

Publication year: 2019

Journal

Monthly Notices of the Royal Astronomical Society Oxford University Press

Book Volume: 489

Pages Range: 1489-1508

Journal Issue: 2

DOI: 10.1093/mnras/stz1618

Abstract

We report the discovery of three stars that, along with the prototype LP 40-365, form a distinct class of chemically peculiar runaway stars that are the survivors of thermonuclear explosions. Spectroscopy of the four confirmed LP 40-365 stars finds ONe-dominated atmospheres enriched with remarkably similar amounts of nuclear ashes of partial O- and Si-burning. Kinematic evidence is consistent with ejection from a binary supernova progenitor; at least two stars have rest-frame velocities indicating they are unbound to the Galaxy. With masses and radii ranging between 0.20 and 0.28Mθ and between 0.16 and 0.60 Rθ, respectively, we speculate these inflated white dwarfs are the partly burnt remnants of either peculiar Type Iax or electron-capture supernovae. Adopting supernova rates from the literature, we estimate that ∼20 LP 40-365 stars brighter than 19 mag should be detectable within 2 kpc from the Sun at the end of the Gaia mission. We suggest that as they cool, these stars will evolve in their spectroscopic appearance, and eventually become peculiar O-rich white dwarfs. Finally, we stress that the discovery of new LP 40-365 stars will be useful to further constrain their evolution, supplying key boundary conditions to the modelling of explosion mechanisms, supernova rates, and nucleosynthetic yields of peculiar thermonuclear explosions.

Authors with CRIS profile

Roberto Raddi Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut Ulrich Heber Professur für Astronomie und Astrophysik

Involved external institutions

University of North Carolina at Chapel Hill US United States (USA) (US) Universität Potsdam DE Germany (DE) Michigan State University US United States (USA) (US) University of California, Berkeley US United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) IT Italy (IT) University of Warwick GB United Kingdom (GB) Boston University US United States (USA) (US) University of Alabama in Huntsville (UAH) US United States (USA) (US) Christian-Albrechts-Universität zu Kiel DE Germany (DE)

How to cite

APA:

Raddi, R., Hollands, M.A., Koester, D., Hermes, J.J., Gansicke, B.T., Heber, U.,... Strader, J. (2019). Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae. Monthly Notices of the Royal Astronomical Society, 489(2), 1489-1508. https://doi.org/10.1093/mnras/stz1618

MLA:

Raddi, Roberto, et al. "Partly burnt runaway stellar remnants from peculiar thermonuclear supernovae." Monthly Notices of the Royal Astronomical Society 489.2 (2019): 1489-1508.

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