Superluminous supernovae: No threat from η carinae

Recently, Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of 10⁴⁴ Joules. It was proposed that the progenitor may have been a massive evolved star similar to Carinae, which resides in our own Galaxy at a distance of about 2.3 kpc. Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given that its rotation axis is unlikely to produce a gamma-ray burst oriented toward Earth, Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We have found that, given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over 10⁴ y and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovaeendocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered dangerous for other reasons. However, due to reddening and extinction by the interstellar medium, Carinae is unlikely to trigger such effects to any significant degree.