Have mirror stars been observed ?

Observations by the MACHO collaboration suggest that a significant proportion of the galactic halo dark matter is in the form of compact objects with typical masses M ∼ 0.5M ⊙. One of the current mysteries is the nature and origin of these objects. We suggest that these objects are stars composed of mirror matter. This interpretation provides a plausible explanation for the inferred masses and abundance of the MA-CHO events. We also comment on the possibility of inferring the existence of mirror supernova's by detecting the neutrino burst in existing underground detectors such as SuperKamiokande. A long standing mystery is the nature of the dark matter in the Universe. In order to shed light on the nature of the dark matter, the Australian-American MACHO collaboration has been searching for Massive Compact Halo objects (MACHO's) in the halo of our galaxy using the gravitational microlensing technique suggested in Ref.[1]. By monitoring source stars in the Large Magellenic Cloud the MACHO collaboration have found 14 MACHO's events[2]. These MACHO's have typical masses M ∼ 0.5M ⊙ and they are estimated to make up a large fraction of the galactic halo f ∼ 0.5[2]. So what are the MACHO's? Over the last few years several conventional candidates for the observed MACHO's have been discussed, such as white dwarfs, brown dwarfs (i.e. Jupiter's), neutron stars, etc. However all of these obvious candidates have either been excluded or appear to be disfavoured for one reason or another (for a recent discussion, see e.g. Ref.[3]). For example, if the MACHO's are brown dwarfs, then it is difficult to understand the estimated mass of the MACHO events (M ∼ 0.5M ⊙) because brown dwarfs are much lighter (< ∼ 0.08M ⊙). In view of the estimated masses of the MACHO's, the most likely conventional interpretation is that they are white dwarfs. However if the MACHO events are white dwarfs then it is very difficult to understand why there are so many of them in the halo of our galaxy. Furthermore there appears to be problems with overproduction of heavy elements and overproduction of light at high redshifts from the luminous stars which were the progenitors of the white dwarfs[4]. Thus, instead of solving the dark matter mystery the MACHO experiment has apparently deepened the mystery. It is also apparently possible that the MACHO's are not actually in the halo of our galaxy but are stars in the …