Astronomy and Astrophysics – Astrophysics
Scientific paper
Aug 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007iaus..240..426d&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
We revisited analytical expressions for the distribution of orbital periods and mass ratios for non-evolved binaries with a B type primary. Selection effects governing the observations were taken into account in order to compare theory with observations. Theory was optimized so as to fit best with the observed P- and q-distributions of non-evolved SB1s and SB2s. The accuracy of the theoretical mass ratio distribution function is severely hindered by the uncertainties on the observations. Our further computations compare statistically the observed distributions of orbital periods and mass ratios of Algols with those obtained from the Brussels binary evolutionary code. Conservative Roche Lobe Over Flow (RLOF) reproduces the observed distribution of orbital periods but fails to explain the observed mass ratios in the range q ? [0.4-1]. In order to obtain a better fit the binaries have to lose a significant amount of matter, without losing too much angular momentum. We tested the following binary evolutionary scenario: The mass acquired by the gainer during RLOF enhances the rotational velocity of the latter. Tidal forces counteract this acceleration. Both mechanisms may speed up the equatorial velocity of the gainer close to its critical value. The luminosity of the gainer is amplified with the accretion luminosity in the equatorial region. Only during a short tine lapse of rapid RLOF spinning-up and accretion luminosity act together to remove mass and angular momentum from the gainer and blow it into the interstellar medium. Consequently also Algols enrich the ISM. The binaries persist for a longer time with a larger mass ratio compared to conservative evolution. Since the mass is blown away from the gainer as an enhanced stellar wind not much angular momentum leaves the system; hence the obtained distribution of the orbital periods of Algols differs not very much from those obtained with the conservative scenario. The proposed time-dependent liberal scenario reproduces the observed distributions of mass ratios and orbital periods of Algols better than conservative evolution would do.
de Greve Jean-Pierre
de Loore Camiel
van Rensbergen Walter
No associations
LandOfFree
Algols contribute to the interstellar mass 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 Algols contribute to the interstellar mass, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Algols contribute to the interstellar mass will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1811120