Rate-Library


Project maintained by Starlib Hosted on GitHub Pages — Theme by mattgraham

STARLIB: Thermonuclear Rate Library

FILES FOR DOWNLOAD

Dowload the Starlib library here. Contents and format are described in the paragraphs below.

Dowload a Fortran script (reduceNet.f) to truncate the Starlib library here. It uses as input the (unzipped) starlib file downloaded by the users and a list of nuclides (sunet.dat; see link below) that the user would like to have in the reaction network. The output is a truncated starlib library that contains only links involving the nuclides listed in sunet.dat.

Download and edit a user-specified list (sunet.dat) of nuclides here. Format: one nuclide per line; each nuclide label must be right-aligned in a field of five; the element symbol comes before the mass number. Examples: “ c12” for 12C; “ ne20” for 20Ne; etc. Special symbols: “ n” for neutron; “ p” for proton; “ d” for deuteron; “ t” for triton. The special case of 26Al: Starlib contains six species of 26Al, the ground state (“ al-6), isomeric state (“ al*6”), three excited levels (“ al01”, “ al02”, “ al03”), and 26Al in thermal equilibrium between ground and isomeric state (“ al26”). The excited levels facilitate, in the hot stellar plasma, the transformation of the ground state to the excited state, and vice versa. The user, depending on the temperature-density conditions of the astrophysical environment to be modeled, needs to make a choice about which and how many of these 26Al species the reaction network should contain. Recommendations: if high temperatures (>0.5 GK) are of interest, it is sufficient to assume thermal equilibrium between the ground and isomeric state in 26Al and only one species is required (“ al26”). At low temperatures (<100 MK) it can be assumed that the ground and isomeric states are not connected via excited 26Al levels and two species (“ al-6” and “ al*6”) are required. If intermediate temperatures are of interest, five species should be included in the network (“ al-6”, “ al*6”, “ al01”, “ al02”, “ al03”; but NOT “ al26”!).

OVERVIEW

Starlib is a library of thermonuclear reaction and laboratory weak interaction rates. It can be used for studies of stellar models and nucleosynthesis. Starlib lists in three columns, for about 50,000 nuclear interactions, the stellar temperature (in GK), the thermonuclear reaction rate (in cm^3 s^-1 mol^-1) or decay rate (in s^-1), and the uncertainty factor of the rate. The library was first introduced in the paper by Sallaska et al. (2013).

The rates and uncertainty factors are listed on a temperature grid from 0.001 GK to 10.0 GK. Starlib incorporates about 70 experimental thermonuclear reaction rates that have been estimated using Monte Carlo methods. These methods were first introduced in papers by Longland et al. (2010) and Iliadis et al. (2016). Starlib has the unique feature of providing, at each temperature grid point, the probability density of the total reaction rate. This feature is important for realistic nucleosynthesis simulations, and has been discussed in the review paper by Iliadis et al. (2015).

The project was initially funded by the National Science Foundation under Award Number AST-1008355. At present, it is funded by NASA under the Astrophysics Theory Program grant 14-ATP14-0007 and by the U.S. Department of Energy under grant number DE-FG02-97ER41041.

STARLIB FORMAT

For each nuclear interaction contained in Starlib, the first line has a fixed format. It contains (i) the interaction type (see below) as an integer value in fields (1:2); (ii) the interacting nuclides before and after the interaction, where each nuclide label is right aligned in a field of size five; (iii) the rate reference label (see below) in fields (45:48); (iv) the interaction character in field 49, where “v”, “w”, and “g” stand for “reverse reaction”, “laboratory weak inetraction”, and “gamma-ray transition”, respectively; (v) the energy released (+) or consumed (-) in the interaction in fields (54:65).

For each interaction contained in Starlib, the following lines list the reaction rates on a 60-value temperature grid from 0.001 GK to 10 GK.

Experimental rates that are not estimated using the Monte Carlo approach are incorporated into Starlib in the following manner: (i) the recommended rate as calculated from the reported low and high rates (left-hand side of Eq. (39) in Longland et al. (2010); (ii) the factor uncertainty is calculated from the reported low and high rates (right-hand side of Eq. (39) in Longland et al. (2010); thus it is explicitly assumed that these rates are lognormally distributed.

INTERACTION TYPE

The integer value between 1 and 11 in fields (1:2) denotes the following interaction types:

  1. e1 –> e2
  2. e1 –> e2 + e3
  3. e1 –> e2 + e3 + e4
  4. e1 + e2 –> e3
  5. e1 + e2 –> e3 + e4
  6. e1 + e2 –> e3 + e4 + e5
  7. e1 + e2 –> e3 + e4 + e5 + e6
  8. e1 + e2 + e3 –> e4
  9. e1 + e2 + e3 –> e4 + e5
  10. e1 + e2 + e3 + e4 –> e5 + e6
  11. e1 –> e2 + e3 + e4 + e5

RATE REFERENCE LABELS

Reaction rates based on experiment:

Reaction rates based on Hauser-Feshbach models:

Weak laboratory decay rates based on experiment:

Weak laboratory decay rates based on theory:

Weak stellar decay rates based on theory:

Gamma-ray decay rates (for excited 26Al levels only):

Individual rates:

PUBLICATIONS

C. Iliadis, K.S. Anderson, A. Coc, F.X. Timmes, and S. Starrfield, Bayesian Estimation of Thermonuclear Reaction Rates, Astrophys. J. 831, 107 (2016).

C. Iliadis, R. Longland, A. Coc, F.X. Timmes, and A.E. Champagne, Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations, J. Phys. G 42, 034007 (2015).

R. Longland, C. Iliadis, A.E. Champagne, J.R. Newton, C. Ugalde, A. Coc, and R. Fitzgerald, Charged-Particle Thermonuclear Reaction Rates: I. Monte Carlo Method and Statistical Distributions, Nucl. Phys. A, 841, 1 (2010).

A.L. Sallaska, C. Iliadis, A.E. Champagne, S. Goriely, S. Starrfield, and F.X. Timmes, Starlib: A Next-Generation Reaction-Rate Library for Nuclear Astrophysics, Astrophys. J. Suppl. 207, 18 (2013).

CONTACT

For questions, contact Christian Iliadis (iliadis “at” unc.edu).