Astronomy and Astrophysics – Astrophysics
Scientific paper
Aug 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007iaus..240..124l&link_type=abstract
Binary Stars as Critical Tools and Tests in Contemporary Astrophysics, International Astronomical Union. Symposium no. 240, he
Astronomy and Astrophysics
Astrophysics
Scientific paper
In general, the mass ratio derived from photometric analyses, q(pe), agrees quite well with the value derived from double-line spectroscopic binary, q(sp), for wide pairs as well as for the close pairs. Therefore one wishes that masses could be determined for single-line systems with the help of photometric mass ratio. It is believed that the large masses determined for early type contact systems may be not reliable or quite wrong due to misleading photometric solution, mass ratios. Of course this includes some of my old published papers as well. The appearance of continuous light variation of their light curves resembles a system with contact configuration. In general, the temperature difference between the components is relatively well determined from the differential depths of the eclipses. Most of these systems have large temperature differences. In mode 3 (most popular) contact configuration of W-D method would automatically ends up with a very large temperature discontinuity at the interface. Even though some of our (with D. Q. Zhou of Peking University) model calculations on circulation in contact atmosphere did arrive at stable flow. (The mathematics just becomes too difficult to handle.) One can easily argue that such temperature discontinuity in a system can not be stable. If one utilizes the mode 1 configuration of the W-D method, there would not be a temperature discontinuity at the interface but than the temperature difference derived would not agree with the differential depths of eclipses. The key problem comes from the fact that there is only very slight difference in the shape of the light curves between a contact system and a very close semidetached system. Essentially there is no inflection point in the contact light curve while there is a slight inflection point for the latter. Since we are dealing with O and early B stars there are serious stellar winds and wind-wind interaction to be considered. These could well smooth out the slight the infection point of a semidetacted light curve so as to mimic a contact light curve. It is suspect that this misleading configuration led to the wrong mass ratio and in turn resulted in very large masses. Therefore one should not trust the automatically arrived contact solution for these systems. Then one should limit the solution to semidetacted configure (mode 3 or 4 of the W-D method) for those systems. Therefore it is recommended that the observations of these systems should be re-analyzed. Since most of these system are single-line binaries one might be able to obtain more reasonable masses with reliable photometric mass ratios.
No associations
LandOfFree
Masses of Early-type contact binary systems 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 Masses of Early-type contact binary systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Masses of Early-type contact binary systems will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-975722