Differential rotation and star-spot evolution on HK Aqr in 2001 and 2002

J R Barnes, D J James, A C Cameron

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38 Citations (Scopus)

Abstract

We present images of the rapidly rotating (P-rot = 0.431 d) M1.5Ve dwarf HK Aqr, from data obtained during 2001 and 2002. Star-spots are found distributed at a range of latitudes during both observing seasons, but unlike other solar-type rapid rotators of higher mass, HK Aqr does not show a strong polar cap at either epoch. In addition to the surface brightness images, we make use of the four-night time-base over which the 2002 observations were made, in order to derive an estimate of the latitudinal dependent rotation on HK Aqr. We find that the equator-lap-pole time lies in the range -1449 to +448 d. Although very small, we are therefore unable to determine whether the degree of differential rotation is in the solar or anti-solar sense.

Original languageEnglish
Pages (from-to)589-599
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume352
DOIs
Publication statusPublished - 1 Aug 2004

Keywords

  • line : profiles
  • methods : data analysis
  • techniques : miscellaneous
  • stars : activity
  • stars : individual : HK Aqr (Gl 890)
  • stars : late-type
  • DUAL-SITE OBSERVATIONS
  • DOPPLER IMAGES
  • MERIDIONAL FLOW
  • G DWARFS
  • PATTERNS
  • PROMINENCES
  • GLIESE-890
  • SUN

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