Abstract
Recent surveys of the Magellanic Clouds have revealed a subtype of Wolf-Rayet (WR) star with peculiar properties. WN3/O3 spectra exhibit both WR-like emission and O3 V-like absorption - but at lower luminosity than O3 V or WN stars. We examine the projected spatial distribution of WN3/O3 stars in the Large Magellanic Cloud as compared to O-type stars. Surprisingly, WN3/O3 stars are among the most isolated of all classes of massive stars; they have a distribution similar to red supergiants dominated by initial masses of 10-15M⊙, and are far more dispersed than classical WR stars or luminous blue variables. Their lack of association with clusters of O-type stars suggests strongly that WN3/O3 stars are not the descendants of single massive stars (30M⊙ or above). Instead, they are likely products of interacting binaries at lower initial mass (10-18M⊙). Comparison with binary models suggests a probable origin with primaries in this mass range that were stripped of their H envelopes through non-conservative mass transfer by a low-mass secondary. We show that model spectra and positions on the Hertzsprung-Russell diagram for binary-stripped stars are consistent with WN3/O3 stars. Monitoring radial velocities with high-resolution spectra can test for low-mass companions or runaway velocities.With lower initialmass and environments that avoid very massive stars, theWN3/O3 stars fit expectations for progenitors of Type Ib and possibly Type Ibn supernovae.
Original language | English (US) |
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Article number | stx3181 |
Pages (from-to) | 772-782 |
Number of pages | 11 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 475 |
Issue number | 1 |
DOIs | |
State | Published - Mar 21 2018 |
Keywords
- Stars: Wolf-Rayet
- Stars: evolution
- Stars: massive
- Stars: winds
- outflows
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science