In today’s 365 Days of Astronomy podcast, two astronomers from the University of Minnesota discuss Eta Carina, a relatively close enigmatic star in the Carina Nebula. In a sense of great timing, new images also released today from the ESO (European Organisation for Astronomical Research in the Southern Hemisphere) reveal amazing detail in the intricate structures of the Carina Nebula, one of the largest and brightest nebulae in the sky. In addition to the gorgeous picture above, enjoy a pan-able image and a video that zooms in on this nebula (also known as NGC 3372), where strong winds and powerful radiation from an armada of massive stars are creating havoc in the large cloud of dust and gas from which the stars were born.
The Carina Nebula is located about 7,500 light-years away in the constellation of the same name (Carina; the Keel). Spanning about 100 light-years, it is four times larger than the famous Orion Nebula and far brighter. It is an intensive star-forming region with dark lanes of cool dust splitting up the glowing nebula gas that surrounds its many clusters of stars.
The glow of the Carina Nebula comes mainly from hot hydrogen basking in the strong radiation of monster baby stars. The interaction between the hydrogen and the ultraviolet light results in its characteristic red and purple color. The immense nebula contains over a dozen stars with at least 50 to 100 times the mass of our Sun. Such stars have a very short lifespan, a few million years at most, the blink of an eye compared with the Sun’s expected lifetime of ten billion years.
One of the Universe’s most impressive stars, Eta Carinae, is found in the nebula. It is one of the most massive stars in our Milky Way, over 100 times the mass of the Sun and about four million times brighter, making it the most luminous star known. Eta Carinae is highly unstable, and prone to violent outbursts, “In the 1840’s it blew up, and for about ten years it was one of the brightest stars in the sky,” said Dr. Kris Davidson in today’s 365 Days of Astronomy Podcast, hosted by Michael Koppelman of Slacker Astronomy. “But it’s almost a thousand times farther away than the brightest star in the sky Sirius, which means the amount of light coming out was really prodigious. After awhile it faded, now we see a nebula blowing out, expanding around it. Clearly its the ejecta the from the star. We can now ‘weigh’ the ejecta, and it is about 10 times the mass of the sun. That’s just the ejecta, the material the star lost about 160 years ago…. We have no right to have such a rare object that close!”
The large and beautiful image displays the full variety of this impressive skyscape, spattered with clusters of young stars, large nebulae of dust and gas, dust pillars, globules, and adorned by one of the Universe’s most impressive binary stars. It was produced by combining exposures through six different filters from the Wide Field Imager (WFI), attached to the 2.2 m ESO/MPG telescope at ESO’s La Silla Observatory, in Chile.