In this paper we consider a quark nova occurring inside an exploding star.
The quark nova ejecta will shock when interacting with the stellar envelope.
When this shock reaches the surface of the star, the energy is radiated away.
We suggest that this energy may be seen in X-rays, and show here that this may
explain some flares seen in the X-ray afterglow of long gamma ray bursts
(GRBs). A quark nova inside an exploding star need not be followed by a GRB, or
the GRB may not be beamed towards us. However, the shock breakout is likely not
beamed and could be seen even in the absence of a GRB. We suggest that XRO
080109 is such an event in which a quark nova occurs inside an exploding star.
No GRB is formed, but the break out of the shock leads to the XRO.Comment: 13 pages, 3 figures, 1 table. To appear in Proceedings for "Compact
stars in the QCD phase diagram II (CSQCD II), May 20-24, 2009, KIAA at Peking
University, Beijing - P. R. China [http://vega.bac.pku.edu.cn/rxxu/csqcd.htm