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

Journal Article · Wed Aug 01 00:00:00 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), Vol. 359; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

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