IUE observations of rapidly rotating low-mass stars in young clusters - The relation between chromospheric activity and rotation

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/185793· OSTI ID:6407342

Simon, T ^[1]

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1. Hawaii Univ., Honolulu (USA)

If the rapid spindown of low-mass stars immediately following their arrival on the ZAMS results from magnetic braking by coronal winds, an equally sharp decline in their chromospheric emission may be expected. To search for evidence of this effect, the IUE spacecraft was used to observe the chromospheric Mg II emission lines of G-M dwarfs in the nearby IC 2391, Alpha Persei, Pleiades, and Hyades clusters. Similar observations were made of a group of X-ray-selected naked T Tauri stars in Taurus-Auriga. The existence of a decline in activity cannot be confirmed from the resulting data. However, the strength of the chromospheric emission in the Mg II lines of the cluster stars is found to be correlated with rotation rate, being strongest for the stars with the shortest rotation periods and weakest for those with the longest periods. This provides indirect support for such an evolutionary change in activity. Chromospheric activity may thus be only an implicit function of age. 31 refs.

• OSTI ID: 6407342
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 359; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
DWARF STARS
EMISSION SPECTRA
ERUPTIVE VARIABLE STARS
MAIN SEQUENCE STARS
MASS
MOTION
ROTATION
SPECTRA
STAR CLUSTERS
STAR EVOLUTION
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CHROMOSPHERES
STELLAR WINDS
T TAURI STARS
VARIABLE STARS
VELOCITY