1 GAMMA RAY BURST TRIGGERING SUPERNOVA EXPLOSION (AND OTHER EFFECTS ON NEIGHBOURING STARS)

Abstract: The initial burst of a gamma ray burst (GRB) is usually followed by a longer-lived afterglow emitted at longer wavelengths. The evidence for a physical connection between GRBs and core collapse supernovae (SN) has increased since the discovery of GRB afterglows [1, 2]. So far SN signatures have been found in only a few GRBs. Here we propose the possibility of a GRB triggering the collapse of a WR or RG star in a binary system producing a SN, and typical signatures. We also look at the effects of GRBs on MS and WD stars in the neighbourhood. The possibility of GRBs retarding star formation in an interstellar cloud is also discussed. Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions and can last from milliseconds to several minutes [3, 4]. It is generally believed that the long-duration gamma ray bursts are associated with the deaths of massive stars in a kind of supernova-like event such as a hypernova [5]. Here we propose that a GRB in a binary system with a progenitor of SN, such as a Wolf-Rayet star or massive red supergiant star could trigger the collapse of the WR or RG star producing a supernova explosion. [6] The gamma-ray energy released in a typical GRB is of the order of 5210 ~ ergs. The flux of gamma rays at a distance of about 50AU is