Kg. Strassmeier et Jb. Rice, Doppler imaging of stellar surface structure XIV. The double-lined pre-main-sequence binary V 824 Arae = HD 1.55555, ASTRON ASTR, 360(3), 2000, pp. 1019-1030
Photospheric Doppler images for both stellar components of the double-lined
pre-main-sequence binary V 824 Ara reveal surface temperature inhomogeneit
ies of up to 1800 K on both stars. The spot geometry on the hotter primary
is dominated by an elongated, tilted, equatorial feature but our maps from
two spectral regions consistently also show a polar spot cooler by 1700 K.
The secondary star has spots mainly at low and very high latitudes but not
a full-sized polar cap. A flux-tube simulation with appropriate stellar mod
els for V 824 Ara suggests that any polar or high-latitude spot must have f
ormed after flux-tube emergence. Generally, the low-latitude spots on both
stellar components appear to be mostly concentrated on the hemispheres turn
ed away from each other while the asymmetry of the polar spot on the primar
y points in the direction of the orbital motion.
We present new radial velocities and use them to re-evaluate the orbital el
ements and to derive absolute parameters for both stellar components. The a
bsolute brightness and mass of the two stars suggest that they are very clo
se to the main sequence - but not yet on the ZAMS - if an inclination of th
e orbital plane (and rotational axes) of 52 degrees is adopted as suggested
by the Doppler imaging. Since both stars are active, we solve for the incl
inations of both stellar components separately and find that the values agr
ee to within their uncertainties.