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Eta Carinae and Giant Eruptions |
WHAT THIS SITE IS ABOUT
Eta Carinae (η Car) is the most luminous, most powerful star visible to the unaided eye. Several facts make it unique for astrophysics.
- It is the only supernova impostor or giant eruption survivor close enough to observe well. In the years 1830--1860 it became tremendously bright and ejected more than 10% of its mass -- but most of the star survived. Eruptions like that are more mysterious than genuine supernovae; and they are so rare that all other known examples occurred far away in other galaxies.
- Eta Car is also the most massive star that can be studied in great detail. Compared to other stars in terms of mass, it's in the upper 0.00000001 percentile.
- Its behavior has repeatedly surprised astronomers, with phenomena that no one predicted. The continuing mass outflow is modulated by a companion star in an eccentric orbit -- which varies the parameters almost like a lab experiment.
- Just before 2000, η Car began to change rapidly. Most likely it has not yet returned to equilibrium after its Great Eruption, and the long-term recovery process is strangely unsteady. This is a clue to instabilities within the most massive stars.
- Its ejecta have exotic spectra, seen in almost no other known object. For example, some of the gaseous blobs mimic a UV laser.
- Its parameters and problems are almost perfectly matched to the Hubble Space Telescope (HST). Hence η Car became one of the most productive of all Hubble targets, and HST revolutionized our knowledge of this topic.
The existence of supernova impostors has been known for decades, but they haven't gotten much attention in books and websites. Published information about η Car is often inaccurate. We hope that this site will begin to fill those gaps.
This website is based mainly at the University of Minnesota, with collaborators at the University of Illinois at Springfield, Nagoya University, and elsewhere.
The original version was created for the HST Treasury Program on Eta Car in 2002-2004, mainly by M. Gray, J.C. Martin, K. Davidson, M. Koppelman, K. Ishibashi, and R.M. Humphreys. The 2018 version has been developed by S. Stangl with contributions by K. Davidson, R.M. Humphreys, and J.C. Martin.
Our public data archive now includes HST observations from 1998 to 2018. We have processed most of the spectra with techniques that allow better spatial resolution than the standard STScI/HST software. Spectra from two large ground-based telescopes are also available here.