Speaker
Description
Aim: To study the effect of uncertainty in 23Mg(p,γ)24Al reaction rate occurring in O-Ne and C-O novae at Classical Nova temperatures by performing a comparative study of one-zone nova nucleosynthesis for different rates of this reaction from the JINA-Reaclib database references.
Background: Stellar burning sites are the primary sources of vast majority of elements heavier than helium. One particular nucleosynthesis site is the classical novae, which are explosions resulting from the accretion of hydrogen-rich material onto a White Dwarf star.
Sensitivity studies, which model the effect of nuclear reaction rate variations on nucleosynthesis predictions, have determined a substantial number of proton capture reactions that have the potential for an observable effect on classical nova nucleosynthesis. One of these reactions is the proton capture on radioactive 23Mg, resulting in 24Al plus a γ ray. The 23Mg(p,γ)24Al reaction rate has been investigated through a variety of experimental and theoretical means over the last two decades.
Method: Joint Institute for Nuclear Astrophysics (JINA) reaction library is an online database for thermonuclear reactions of astrophysical importance. The current version of the Reaclib stores reaction rates as a function of temperature in the seven-parameter rate parameterization of Thielemann et al. (1987) and F.-K. Thielemann (1995) interpolation. For the 23Mg(p,γ)24Al reaction rate, Reaclib provides 6 different sources of reference. Each of these references evaluates the rate with an analytical expression. The evaluated rates have been compared to the NuGrid default rate used in one-zone nova nucleosynthesis simulations on the UVic astrohub web server TINA (Training In Nuclear Astrophysics) at characteristic nova temperatures. The differences between analytical and NuGrid default reaction rates have been estimated and their effect on the abundances of intermediate-mass elements predicted by one-zone nova nucleosynthesis simulations have been studied. The rate of the 23Mg(p,γ)24Al reaction was evaluated with available analytical approximations for NuGrid O-Ne and C-O nova models with masses of white dwarf ranging from 1.15 M⊙ to 1.3 M⊙ for mass accretion rate dM/dt = 2×10−10 M⊙/yr. The three different white dwarf central temperatures, TWD = 7, 10, and 12 MK. The accreted material has the 50% pre-mixed Weiss and Barcelona initial compositions. The peak H-burning temperatures in these models reach the values of 257, 436, and 355 MK.
Result: The reaction rate uncertainty study has found that the large variations of the 23Mg(p,γ)24Al rate between its different available sources result in significant variations of the predicted abundances of H, He, Li, C, O, N, F, Ne, Na, Mg, Al, Si, S, P, Cl, Ar, K and Ca isotopes. Also, the 23Mg(p,γ)24Al reaction rate will be directly measured and studied experimentally in the near future using the DRAGON (Detector of Recoils And Gammas Of Nuclear reactions) facility at TRIUMF, Vancouver, BC, Canada.
| Length of presentation requested | Oral presentation: 8 min + 2 min questions (Poster-type talk) |
|---|---|
| Please select between one and three keywords related to your abstract | Nucleosynthesis |
| 2nd keyword (optional) | Nuclear physics - theory |
| 3rd keyword (optional) | Interstellar Medium |
