The coronal structure of Speedy Mic - I: A densely packed prominence system beyond co-rotation

N.J. Dunstone, J.R. Barnes, Andrew Collier Cameron, Moira Mary Jardine

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

We present new observations of the prominence system on the K3 dwarf Speedy Mic (BO Mic, HD 197890). Using an improved technique to track the absorption features in H alpha we find a very active prominence system with approximately 10 prominences on the observable hemisphere per rotation. From a total of 25 prominences, we find an average axial distance of (2.85 +/- 0.54) R-* which is twice the corotation radius above the stellar surface. We discuss the consequences of these observations on the nature of the supporting magnetic structures. Two consecutive nights, with complete phase coverage, combined with a further night after a three-night gap allow us to study the evolution of the prominence system on two different time-scales. Several of the prominences have counterparts at similar phases on consecutive nights. During this interval, many prominences show evidence for evolution in their heights and phases of observation. Five nights (13 rotation cycles) later, we recover many prominences at approximately the same phases. Whilst individual prominences change axial distances or appear/reappear from night-to-night, the underlying prominence supporting structures appear to be stable over as many as 13 stellar rotations.

Original languageEnglish
Pages (from-to)530-538
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume365
Issue number2
DOIs
Publication statusPublished - 11 Jan 2006

Keywords

  • line : profiles
  • methods : data analysis
  • stars : activity
  • circumstellar matter
  • stars : individual : Speedy Mic (HD 197890)
  • stars : late-type
  • X-RAY SPECTROSCOPY
  • XMM-NEWTON VIEW
  • AB-DORADUS
  • DIFFERENTIAL ROTATION
  • STELLAR CORONAE
  • DOPPLER IMAGES
  • EXPLORER OBSERVATIONS
  • MAGNETIC TOPOLOGY
  • STARS
  • PATTERNS

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