Rotation, turbulence and evidence for magnetic fields in southern dwarfs
Abstract
We model high-resolution spectra using a simple radiative transfer analysis to derive projected rotational velocities (v sin i) and macroturbulent velocity dispersions (v_mac) for 49 southern dwarf stars (including many first-ever measurements). We compare our results with previous values, and estimate rotation periods (P_rot) and sin i values where possible. We confirm that v_mac generally decreases with decreasing temperature for T_eff >= 5000 K. Magnetically active stars tend to show enhanced values of v_mac. This may be due to a difference in the mean stellar convective properties, a change in the mean stellar temperature structure, or a combination of both. We identify a group of stars that exhibit correlations between the derived velocities and line Lande g_eff values, implying the presence of significant surface magnetic flux.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 1997
- DOI:
- 10.1093/mnras/284.4.803
- Bibcode:
- 1997MNRAS.284..803S
- Keywords:
-
- CONVECTION;
- TURBULENCE;
- STARS: LATE-TYPE;
- STARS: MAGNETIC FIELDS;
- STARS: ROTATION