Hubble Captures "Supernova Impostor" AT2019abn: A Cosmic Enigma
NASA's Hubble Space Telescope has delivered a breathtaking image of a peculiar cosmic event, designated AT2019abn. This phenomenon, classified as a "supernova impostor," presents a fascinating puzzle for astronomers, challenging our understanding of stellar evolution and catastrophic events.
What is a Supernova Impostor?
Supernova impostors are celestial explosions that, at first glance, mimic the explosive death of a star – a supernova. However, the key difference lies in their progenitor stars. Unlike true supernovae, these impostors do not result in the complete destruction of the star that produced them. Instead, they are considered a class of exceptionally powerful novae, sometimes referred to as Type V supernovae, analogs to Eta Carinae, or giant eruptions from Luminous Blue Variables (LBVs).
These impostors manifest as surprisingly faint supernovae with a spectral type of IIn. This classification indicates the presence of hydrogen in their spectrum and narrow spectral lines, suggesting relatively slow gas speeds. The outbursts of these impostors can dramatically increase a star's brightness, exceeding their pre-outburst states by several magnitudes. Their peak absolute visual magnitudes range from -11 to -14, making them as luminous as some of the most radiant stars in the universe.
The Mystery of the Mechanism
The exact trigger mechanism behind these spectacular, yet survivable, outbursts remains an active area of research. Current theories suggest that these events might occur when a star violates the classical Eddington luminosity limit. This violation can initiate severe mass loss, leading to these unusually energetic eruptions. If the ratio of radiated energy to kinetic energy is high, similar to what is observed in Eta Carinae, it's estimated that the ejected mass could be around 0.16 solar masses.
For the Aspiring Astronomer
For amateur astronomers looking to delve into the study of supernovae and neutron stars, accessing data can be a challenge. A great starting point is NASA's vast repository of data, which is freely available and often includes articles on various astronomical phenomena, including Type II neutron stars. Additionally, resources like Wikipedia, SPACE.com, and local library archives can provide a wealth of in-depth information to fuel your research.
