STABLE CARBON PRODUCTION ON ACCRETING NEUTRON STARS AT THE ORIGIN OF SUPERBURSTS

Image Credit: David A. Hardy & PPARC

Accreting neutron stars exhibit bursts due to nuclear burning of hydrogen/helium and rarely even carbon. The carbon flashes generate the superbusts. The carbon is produced during the hydrogen/helium flashes. However the amount of carbon produced in hydrogen/helium flashes is insufficient to power the superbursts.

To produce the amount of carbon necessary to trigger the superbursts is required a "stable burning" of hydrogen/helium in addition to high accretion rates. But the accretion rates observed in superbursts (10^[- 9] solar masses/year) are too low to produce the amount of carbon necessary for superbursts.
In a recent paper (Keek, Heger 2016) the authors find that the hot CNO burning of hydrogen heats the neutron star envelope accelerating the burning of helium (and thus the production of carbon) before the conditions of a helium flash are reached. This acceleration of the production rate of carbon makes it possible superbursts even with growth rates lower, consistent as order of magnitude with those observed (10 ^ [- 9] solar masses / year).

Read more>>
http://arxiv.org/abs/1508.06630
http://mnrasl.oxfordjournals.org/content/456/1/L11.abstract

Comments

A METHOD TO TEST THE EXISTENCE OF REGULAR BLACK HOLES

Illustration of a black hole. Image Credit & Copyright: Alain Riazuelo The existence of the singularity is an intrinsic problem of the General Relativity (GR). At the fundamentally level, the resolution of the problem of the singularity lies with the expectation that under situations where quantum effects become strong, the behavior of gravity could possibly greatly deviate from that predicted by the classical theory of GR. Regular black hole solution are proposed with the same spacetime geometry outside the horizon as the traditional black hole, but bears no singularity inside. Whether or not black hole singularities should exist, they would be covered by the black hole horizon. The black hole horizon serves as an information curtain hindering outside observers from directly observing the interior structure of the black hole, and determining that whether or not the black hole singularity does really exist. A method is needed to check the correctness of the new constructions ...

ORBITAL PERIODS OF THE PLANETS

For orbital period generally we refer to the sidereal period, that is the temporal cycle that it takes an object to make a full orbit, relative to the stars. This is the orbital period in an inertial (non-rotating) frame of reference (365,25 days for the earth).

Astrophysics collection (March 11, 2016)

Latest astrophysics news Rotation curves of galaxies as a test of MOND? Galaxies are rotating with such speed that the gravity generated by their observable matter could not possibly hold them together. In a recent paper ( Haghi et al. 2016 ) the authors test the Modified Newtonian Dynamics (MOND). Read>> A binary origin for a central compact object (CCO)? Doroshenko et al. 2016 investigate the possible binary origin of the CCO XMMUJ173203.3-344518 . Read>> Rapidly rotating pulsars as possible sources of fast radio bursts (FRB) In a recent paper ( Lyutikov et al. 2016 ) the authors discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars. Read>> Supernovae from WD-WD direct collisions In recent years it was suggested that WD-WD direct collisions (probably extremely rare and occurring only in dense stellar clusters) provide an additional channel for supernova...

SpaceTime

Search This Blog