The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores

Details The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores

Jan 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...420..348t&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 420, no. 1, p. 348-363

Other

39

Abundance, Degenerate Matter, Stellar Interiors, Supernovae, Wave Propagation, White Dwarf Stars, Carbon, Conductive Heat Transfer, Neon, Nuclear Fusion, Oxygen, Reaction Kinetics, Stellar Evolution

Scientific paper

We determine the speeds, and many other physical properties, of flame fronts that propagate inward into degenerate and semidegenerate cores of carbon and oxygen (CO) and neon and oxygen (NeOMg) white dwarfs when such flames are bounded on their exterior by a convective region. Combustion in such fronts, per se, is incomplete, with only a small part of the initial mass function burned. A condition of balanced power is set up in the star where the rate of energy emitted as neutrinos from the convective region equals the power available from the unburned fuel that crosses the burning front. The propagation of the burning front itself is in turn limited by the temperature at the base of the convective shell, while cannot greatly exceed the adiabatic value. Solving for consistency between these two conditions gives a unique speed for the flame. Typical values for CO white dwarfs are a few hundredths of a centimeter per second. Flames in NeOMg mixtures are slower. Tables are presented in a form that can easily be implemented in stellar evolution codes and yield the rate at which the convective shell advances into the interior. Combining these velocities with the local equations for stellar structure, we find a minimum density for each gravitational potential below with the local equations for stellar structure, we find a minimum density for each gravitational potential below which the flame cannot propagate, and must die. Although detailed stellar models will have to be constructed to resolve some issues conclusively, our results that a CO white dwarf inginted at its edge will not burn carbon all the way to its center unless the mass of the white dwarf exceeds 0.8 solar mass. On the other hand, it is difficult to ignite carbon burning by compression alone anywhere in a white dwarf whose mass does not exceed 1.0 solar mass. Thus, compressionally ignited shell carbon burning in an accreting CO dwarf almost certainly propagates all the way to the center of the star. Implications for neutron star formation, and Type Ia supernova models, are briefly discussed. These are also applicable to massive stars in the about 10-12 solar mass range which ignite neon burning off center.

Affiliated with

Also associated with

No associations

Rating

The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores 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 The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The conductive propagation of nuclear flames. 2: Convectively bounded flames in C + O and O + NE + MG cores will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-865699