Strong Variability in AzV 493, an Extreme Oe-type Star in the SMC

M. S. Oey; N. Castro; M. Renzo; I. Vargas-Salazar; M. W. Suffak; M. Ratajczak; J. D. Monnier; M. K. Szymanski; G. D. Phillips; N. Calvet; A. Chiti; G. Micheva; K. C. Rasmussen; R. H. D. Townsend

doi:10.3847/1538-4357/acb690

The Astrophysical Journal (Jan 2023)

Strong Variability in AzV 493, an Extreme Oe-type Star in the SMC

M. S. Oey,
N. Castro,
M. Renzo,
I. Vargas-Salazar,
M. W. Suffak,
M. Ratajczak,
J. D. Monnier,
M. K. Szymanski,
G. D. Phillips,
N. Calvet,
A. Chiti,
G. Micheva,
K. C. Rasmussen,
R. H. D. Townsend

Affiliations

M. S. Oey: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]
N. Castro: ORCiD; Leibniz-Institut für Astrophysik Potsdam (AIP) , An der Sternwarte 16, D-14482, Potsdam, Germany
M. Renzo: ORCiD; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USA
I. Vargas-Salazar: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]
M. W. Suffak: ORCiD; Department of Physics and Astronomy, Western University , London, ON N6A 3K7, Canada
M. Ratajczak: ORCiD; Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
J. D. Monnier: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]
M. K. Szymanski: ORCiD; Astronomical Observatory, University of Warsaw , Al. Ujazdowskie 4, 00-478 Warszawa, Poland
G. D. Phillips: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]
N. Calvet: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]
A. Chiti: ORCiD; Department of Astronomy & Astrophysics, University of Chicago , 5640 South Ellis Avenue, Chicago, IL 60637, USA; Kavli Institute for Cosmological Physics, University of Chicago , Chicago, IL 60637, USA
G. Micheva: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]; Present address: Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482, Potsdam, Germany
K. C. Rasmussen: ORCiD; Astronomy Department, University of Michigan , 1085 South University Avenue, Ann Arbor, MI 48109, USA ; [email protected]; Present address: Astronomy Department, University of Washington , Box 351580, Seattle, WA 98195, USA
R. H. D. Townsend: ORCiD; Astronomy Department, University of Wisconsin , Madison, WI 53706, USA

DOI: https://doi.org/10.3847/1538-4357/acb690
Journal volume & issue: Vol. 947, no. 1
p. 27

Abstract

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We present 18 yr of OGLE photometry together with spectra obtained over 12 yr revealing that the early Oe star AzV 493 shows strong photometric (Δ I 0.93) orbit. We propose that close interaction at periastron excites ejection of the decretion disk, whose variable emission-line spectrum suggests separate inner and outer components, with an optically thick outer component obscuring both the stellar photosphere and the emission-line spectrum of the inner disk at early phases in the photometric cycle. It is plausible that AzV 493’s mass and rotation have been enhanced by binary interaction followed by the core-collapse supernova explosion of the companion, which now could be either a black hole or a neutron star. This system in the Small Magellanic Cloud can potentially shed light on OBe decretion disk formation and evolution, massive binary evolution, and compact binary progenitors.

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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