Discovery of a runaway star likely ejected by a Type Iax Supernova

Fuente: arXiv
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Main Authors: Bhat, A., Hollands, M., Dorsch, M., Geier, S., Heber, U., Koester, D., Pakmor, R., Shen, Ken J.
Format: Preprint
Published: 2026
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author Bhat, A.
Hollands, M.
Dorsch, M.
Geier, S.
Heber, U.
Koester, D.
Pakmor, R.
Shen, Ken J.
author_facet Bhat, A.
Hollands, M.
Dorsch, M.
Geier, S.
Heber, U.
Koester, D.
Pakmor, R.
Shen, Ken J.
contents Over the past decade, runaway stars have been identified, believed to originate either as surviving donors of Type Ia supernovae or as partially deflagrated accretors producing Type Iax supernovae. While the former have been extensively studied recently, the origins of the latter (also called LP 40-365 type stars) remain under-explored and therefore less well understood. So far seven such objects are known. In this paper, we report the discovery of a new LP 40-365 type runaway star, notably hotter than previously studied members of this class. Spectral analysis confirms that its atmosphere is neon- and oxygen-dominated, consistent with earlier analyses of other LP 40-365 type stars. Kinematic analysis indicates that the star has a high probability of being unbound from the Galaxy and was most likely ejected from the Galactic disk approximately 2.8 Myr ago with an ejection velocity exceeding 600 km/s. This result further emphasizes the discrepancy between the abundance yields and kick velocities predicted by white dwarf deflagration models and those observed in stars of LP 40-365 type, underscoring the need for a reassessment of such systems.
format Preprint
id arxiv_https___arxiv_org_abs_2602_23900
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Discovery of a runaway star likely ejected by a Type Iax Supernova
Bhat, A.
Hollands, M.
Dorsch, M.
Geier, S.
Heber, U.
Koester, D.
Pakmor, R.
Shen, Ken J.
Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
Over the past decade, runaway stars have been identified, believed to originate either as surviving donors of Type Ia supernovae or as partially deflagrated accretors producing Type Iax supernovae. While the former have been extensively studied recently, the origins of the latter (also called LP 40-365 type stars) remain under-explored and therefore less well understood. So far seven such objects are known. In this paper, we report the discovery of a new LP 40-365 type runaway star, notably hotter than previously studied members of this class. Spectral analysis confirms that its atmosphere is neon- and oxygen-dominated, consistent with earlier analyses of other LP 40-365 type stars. Kinematic analysis indicates that the star has a high probability of being unbound from the Galaxy and was most likely ejected from the Galactic disk approximately 2.8 Myr ago with an ejection velocity exceeding 600 km/s. This result further emphasizes the discrepancy between the abundance yields and kick velocities predicted by white dwarf deflagration models and those observed in stars of LP 40-365 type, underscoring the need for a reassessment of such systems.
title Discovery of a runaway star likely ejected by a Type Iax Supernova
topic Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2602.23900