Sher 25: Pulsating but apparently alone

William D. Taylor, Christopher J. Evans, Sergio Simón-Díaz, Hugues Sana, Norbert Langer, Nathan Smith, Stephen J. Smartt

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The blue supergiant Sher 25 is surrounded by an asymmetric, hourglass-shaped circumstellar nebula, which shows similarities to the triple-ring structure seen around SN 1987A. From optical spectroscopy over six consecutive nights, we detect periodic radial velocity variations in the stellar spectrum of Sher 25 with a peak-to-peak amplitude of ~ 12 km s-1 on a time-scale of about 6 d, confirming the tentative detection of similar variations by Hendry et al. From consideration of the amplitude and time-scale of the signal, coupled with observed line profile variations, we propose that the physical origin of these variations is related to pulsations in the stellar atmosphere, rejecting the previous hypothesis of a massive, short-period binary companion. The radial velocities of two other blue supergiants with similar bipolar nebulae, SBW1 and HD 168625, were also monitored over the course of six nights, but these did not display any significant radial velocity variations.

Original languageEnglish (US)
Pages (from-to)1483-1490
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume442
Issue number2
DOIs
StatePublished - Jun 2014

Keywords

  • Stars: evolution
  • Stars: individual: Sher 25
  • Type
  • stars: early

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Taylor, W. D., Evans, C. J., Simón-Díaz, S., Sana, H., Langer, N., Smith, N., & Smartt, S. J. (2014). Sher 25: Pulsating but apparently alone. Monthly Notices of the Royal Astronomical Society, 442(2), 1483-1490. https://doi.org/10.1093/mnras/stu925