Tests of two convection theories for red giant and red supergiant envelopes

Details Tests of two convection theories for red giant and red supergiant envelopes Tests of two convection theories for red giant and red supergiant envelopes

Feb 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...440..297s&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 440, no. 1, p. 297-302

Statistics

Applications

34

Late Stars, Red Giant Stars, Stellar Convection, Stellar Envelopes, Stellar Evolution, Stellar Models, Supergiant Stars, Calibrating, Hertzsprung-Russell Diagram, Mathematical Models, Stellar Mass

Scientific paper

Two theories of stellar envelope convection are considered here in the context of red giants and red supergiants of intermediate to high mass: Boehm-Vitense's standard mixing-length theory (MLT) and Canuto & Mazzitelli's new theory incorporating the full spectrum of turbulence (FST). Both theories assume incompressible convection. Two formulations of the convective mixing length are also evaluated: l proportional to the local pressure scale height (HP) and l proportional to the distance from the upper boundary of the convection zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red zone (z). Applications to test both theories are made by calculating stellar evolutionary sequences into the red phase of core helium burning. Since the theoretically predicted effective temperatures for cool stars are known to be sensitive to the assigned value of the mixing length, this quantity has been individually calibrated for each evolutionary sequence. The calibration is done in a composite Hertzsprung-Russell diagram for the red giant and red supergiant members of well-observed Galactic open clusters. The MLT model requires the constant of proportionality for the convective mixing length to vary by a small but statistically significant amount with stellar mass, whereas the FST model succeeds in all cases with the mixing lenghth simply set equal to z. The structure of the deep stellar interior, however, remains very nearly unaffected by the choices of convection theory and mixing lenghth. Inside the convective envelope itself, a density inversion always occurs, but is somewhat smaller for the convectively more efficient MLT model. On physical grounds the FST model is preferable, and seems to alleviate the problem of finding the proper mixing length.

Affiliated with

Also associated with

No associations

Rating

Tests of two convection theories for red giant and red supergiant envelopes 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 Tests of two convection theories for red giant and red supergiant envelopes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tests of two convection theories for red giant and red supergiant envelopes will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1630860