An atmospheric model for UZ Librae from mean Hα-line profiles

Details An atmospheric model for UZ Librae from mean Hα-line profiles An atmospheric model for UZ Librae from mean Hα-line profiles

Jul 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004a%26a...421..295z&link_type=abstract

Astronomy and Astrophysics, v.421, p.295-303 (2004)

Astronomy and Astrophysics

Astrophysics

3

Stars: Late-Type, Stars: Activity, Stars: Atmospheres, Stars: Chromospheres, Stars: Individual: Uz Lib

Scientific paper

We present the results from fitting a semi-empirical atmospheric model including a chromosphere and a transition region to the mean (seasonal) Balmer Hα line profiles of the RS CVn-type K0-giant UZ Librae. As a first step, a static 1D spherical model was applied to the mean component of the Hα-emission core and its profile. The main result of the fitting is that the transition region begins at a log mass depth of -1.8 g cm-2 at a temperature of 7400 K (approximately 3000 K warmer than the photosphere) and then has a steep increase to the peak temperature of ≈106 K. A stellar model in plane-parallel mode with ``partial-frequency redistribution'' option in the line transfer gave roughly the best fit. Subsequently, two-Gaussian fitting of the phase-dependent Hα -line profiles yields a complex velocity field. The radial velocities, from both the absorption reversal and the main emission component, display rotational and/or orbital modulation. The largest differences between consecutive line profiles occur mostly in the red line wings, suggesting the existence of both an inward-pointed velocity field and sporadic radiation events possibly related to flares. The total Hα emission, as derived from the equivalent width, possibly also displays rotational modulation. Indirect evidence is presented for the existence of circumstellar matter in form of an Hα absorption shell. Finally, a preliminary elemental abundance analysis suggests sub-solar metallicity of [M/H]≈ -0.5 dex based on ATLAS models, or -0.7 dex based on PHOENIX models.

Affiliated with

Also associated with

No associations

Rating

An atmospheric model for UZ Librae from mean Hα-line profiles does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with An atmospheric model for UZ Librae from mean Hα-line profiles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An atmospheric model for UZ Librae from mean Hα-line profiles will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1074878