* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Algol Binaries


L

Posts: 131433
Date:
Algol-type binaries
Permalink  
 


Title: Hidden population of Algols
Author: O. Yu. Malkov, D. A. Kovaleva, L. R. Yungelson, E. A. Avvakumova, D. A. Chulkov, O. B. Dluzhnevskaya, A. Yu Kniazev

We present results of Monte Carlo simulation aiming at the estimate of the frequency of semi-detached Algol-type binaries among the stars observed as single ones. When account is made for various detection biases (mostly due to inclination of orbits), the fraction of Algols among Galactic disk stars appears to be 0.1--0.2%. However, this number should be regarded as a lower limit only, since there are still unaccounted selection effects and other types of photometrically unresolved binaries. Hidden binarity appears to be an important phenomenon that should be taken into account when considering stellar statistics and construction of fundamental relations between stellar parameters.

Read more (1483kb, PDF)



__________________


L

Posts: 131433
Date:
Algol Binaries
Permalink  
 


Title: New Evidence of Magnetic Interactions between Stars from 3D Doppler Tomography of Algol Binaries: Beta Per and RS Vul
Authors: Mercedes T. Richards, Michail I. Agafonov, Olga I. Sharova

Time-resolved H-alpha spectra of magnetically-active interacting binaries have been used to create 3D Doppler tomograms by means of the Radioastronomical Approach. This is the first 3D reconstruction of Beta Per, with RS Vul for comparison. These 3D tomograms have revealed evidence of the mass transfer process (gas stream, circumprimary emission, localised region, absorption zone), as well as loop prominences and coronal mass ejections (CMEs) in Beta Per and RS Vul that could not be discovered from 2D tomograms alone. The gas stream in both binaries may have been deflected beyond the central plane by the mass loser's magnetic field. The stream was more elongated along the predicted trajectory in RS Vul than in Beta Per, but not as pronounced as in U CrB (stream-state). The loop prominence reached maximum Vz velocities of 155 km/s compared to 120 km/s in Beta Per, while the CME reached a maximum Vz velocity of +150 km/s in RS Vul and +100 km/s in Beta Per. The 3D tomograms show that the gas flows are not symmetric relative to the central plane and are not confined to that plane; a result confirmed by recent 15GHz VLBI radio images of Beta Per. Both the 3D H-alpha tomography and the VLBI radio images support an earlier prediction of the superhump phenomenon in Beta Per: that the gas between the stars is threaded with a magnetic field even though the hot B8V mass gaining star is not known to have a magnetic field.

Read more (2430kb, PDF)



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard