Thursday, October 31, 2013

'Witch Head' Brews Baby Stars

An infrared portrait of the Witch Head nebula from NASA's Wide-field Infrared Survey Explorer, or WISE, shows billowy clouds where new stars are brewing. Image credit: NASA/JPL-Caltech

A witch appears to be screaming out into space in this new image from NASA's Wide-Field Infrared Survey Explorer, or WISE. The infrared portrait shows the Witch Head nebula (IC 2118), named after its resemblance to the profile of a wicked witch. Astronomers say the billowy clouds of the nebula, where baby stars are brewing, are being lit up by massive stars. Dust in the cloud is being hit with starlight, causing it to glow with infrared light, which was picked up by WISE's detectors.

The Witch Head nebula is estimated to be hundreds of light-years away in the Orion constellation, just off the famous hunter's knee. 

Radio observations show substantial carbon monoxide emission throughout parts of IC 2118 an indicator of the presence of molecular clouds and star formation in the nebula. In fact candidates for pre-main sequence stars and some classic T-Tauri stars have been found deep within the nebula.

The molecular clouds of IC 2118 are probably juxtaposed to the outer boundaries of the vast Orion-Eridanus bubble, a giant supershell of molecular hydrogen blown by the high mass stars of the Orion OB1 association. As the supershell expands into the interstellar medium, favorable circumstances for star formation occur. IC 2118 is located in one such area.The wind blown appearance and cometary shape of the bright reflection nebula is highly suggestive of a strong association with the high mass luminous stars of Orion OB1. The fact that the heads of the cometary clouds of IC2118 point northeast towards the association is strong support of that relationship.

WISE was recently "awakened" to hunt for asteroids in a program called NEOWISE. The reactivation came after the spacecraft was put into hibernation in 2011, when it completed two full scans of the sky, as planned.

Credit: NASA

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