TY - JOUR

T1 - The Wilson-Bappu effect of the MgII k line - dependence on stellar temperature, activity and metallicity

A1 - Elgaroy,O.

A1 - Engvold,O.

A1 - Lund,Niels

AU - Elgaroy,O.

AU - Engvold,O.

AU - Lund,Niels

PB - E D P Sciences

PY - 1999

Y1 - 1999

N2 - The Wilson-Bappu effect is investigated using accurate absolute magnitudes of 65 stars obtained through early release of data from the Hipparcos satellite together with MgII k fine widths determined from high resolution spectra observed with the International Ultraviolet Explorer (IUE) observatory. Stars of spectral classes F, G, K and M and luminosity classes I-V are represented in the sample. Wilson-Bappu relations for the Mg II k line for stars of different temperatures i.e. spectral classes are determined. The relation varies with spectral class and there is a significant scatter of the line widths around the regression lines. The sample contains slowly rotating stars of different activity levels and is suitable for investigations of a possible relation between line width and stellar activity. A difference in behavior between dwarfs and giants (and supergiants) of spectral class K seems to be present. Magnetic activity affects the width of the Mg II k line in dwarfs. Metallicity is found to influence the Mg II k line width in giants and supergiants. Possible interpretations of the new results are briefly discussed.

AB - The Wilson-Bappu effect is investigated using accurate absolute magnitudes of 65 stars obtained through early release of data from the Hipparcos satellite together with MgII k fine widths determined from high resolution spectra observed with the International Ultraviolet Explorer (IUE) observatory. Stars of spectral classes F, G, K and M and luminosity classes I-V are represented in the sample. Wilson-Bappu relations for the Mg II k line for stars of different temperatures i.e. spectral classes are determined. The relation varies with spectral class and there is a significant scatter of the line widths around the regression lines. The sample contains slowly rotating stars of different activity levels and is suitable for investigations of a possible relation between line width and stellar activity. A difference in behavior between dwarfs and giants (and supergiants) of spectral class K seems to be present. Magnetic activity affects the width of the Mg II k line in dwarfs. Metallicity is found to influence the Mg II k line width in giants and supergiants. Possible interpretations of the new results are briefly discussed.

KW - stars : activity

KW - stars : chromospheres

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

IS - 1

VL - 343

SP - 222

EP - 228

ER -