ABSTRACT

Eta Carinae has fascinated astronomers since brightening in the 1840s to rival Sirius but then fading to the unaided eye. Today the Homunculus, a massive, dusty, molecular bipolar shell expands outward at 600 km/s. Its kinetic energy approaches that of a supernova event. The surviving core, a 5.54-year binary, is obscured in our line of sight by 4 to 5 magnitudes of primary wind. In another direction, the secondary wind periodically carves a cavity out of the primary wind, releasing prodigious amounts of far ultraviolet radiation that ionizes fossil winds from previous cycles. During each periastron passage, as happened this past August, the secondary star plunges deeply into the primary wind; its FUV radiation is captured and the fossil winds recombine leading to an on/off effect of a source exciting an astrophysical-size sample. Over the past 17 years, my colleagues and I have shared multispectral studies and 3D hydrodynamic modeling of this fascinating system. We have gained much insight about the end-stages of present day, very massive, short-lived stars and the first stars in our early universe.

About the Speaker:

Ted Gull has been an astrophysicist at Goddard since 1977. He worked with the International Ultraviolet Explorer, Hubble Space Telescope, was Mission Scientist for the Astro-1 Mission that flew in December 1990 and served as Associate Chief of the Laboratory for Astronomy and Solar Physics. Previously he developed imaging spectrographs for the NASA Learjet and the 4-Meter Telescopes at Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory. He helped develop the shuttle Spacelab through the Astronaut Office at Johnson Space Center. He will retire this June.