[en] We report new spectroscopic observations of the magnetic Of?p star HD 148937 obtained since 2015 that differ qualitatively from its extensive historical record of weak, periodic spectral variations. This remarkable behaviour represents clear evidence for an unprecedented change in the character of variability of the star. In this paper, we describe the new spectral properties and compare them to the previous line profiles. Based on measurements of the radial velocities of the C III/N III emission lines near 4640 Å and the C IV absorption lines near 5800 Å, we infer that HD 148937 is likely a high-mass, double-lined spectroscopic binary. Combining the spectroscopic orbit with an archival interferometric measurement of the apparent separation of the equal brightness components, we tentatively conclude that HD 148937 consists of two O-type stars with masses of approximately 34 and 49 M[SUB]⊙[/SUB], orbiting in an eccentric (e = 0.75), long-period (P[SUB]orb[/SUB] ˜ 26 yr) orbit. We discuss the potential relationship of the binary system to the peculiar properties of HD 148937, and propose future observations to refine the orbital and stellar properties.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Wade, G. A.; Department of Physics & Space Science, Royal Military College of Canada, PO Box 17000 Station Forces, Kingston, ON K7K 0C6, Canada
Smoker, J. V.; European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19, Chile
Evans, C. J.; UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
Howarth, I. D.; Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK
Barba, R. ; Departamento de Física y Astronomía, Universidad de La Serena, Av. Cisternas 1200, La Serena, Chile
Cox, N. L. J.; Anton Pannekoek Institute for Astronomy, University of Amsterdam, NL-1090 GE Amsterdam, The Netherlands ; ACRI-ST, 260 Route du Pin Montard, Sophia Antipolis, France
Morrell, N.; Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena, Chile
Nazé, Yaël ; Université de Liège - ULiège > Groupe d'astrophysique des hautes énergies (GAPHE)
Cami, J.; Department of Physics and Astronomy and Centre for Planetary Science and Exploration (CPSX), The University of Western Ontario, London, ON N6A 3K7, Canada ; SETI Institute, 189 Bernardo Ave, Suite 100, Mountain View, CA 94043, USA
Farhang, A.; Department of Physics and Astronomy and Centre for Planetary Science and Exploration (CPSX), The University of Western Ontario, London, ON N6A 3K7, Canada ; School of Astronomy, Institute for Research in Fundamental Sciences, 19395-5531 Tehran, Iran
Walborn, N. R.; Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Arias, J.; Departamento de Física y Astronomía, Universidad de La Serena, Av. Cisternas 1200, La Serena, Chile
Gamen, R.; Instituto de Astrofísica de La Plata, CONICET-UNLP and Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque, s/n, La Plata, Argentina)
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