Rosette Nebula and HOBYS

Last week there was a meeting in Madrid showcasing the first results from ESA’s new space-borne infrared observatory Herschel. All the talks from the workshop are online. Many amazing images were released last week but one that seems to have slipped by is this incredible montage of data from the Rosette Nebula. [RSS readers click here for image]

The image was taken as part of the oddly-named HOBYS (Herschel imaging survey of OB Young Stellar objects) program studying young, massive stars. Giant OB stars are an important part of the dynamics of galaxies. They die in massive explosions, live extremely energetic lives and shape the evolution of nearby regions with their powerful radiation. Understanding where they come from and how they form is a big deal in star-formation research. It also appears to be a process quite different to that which seems to form the kind of low-mass object I look at in my own resesarch.

Herschel allows us to look deeper and farther, such that we can can see lots of the precursors of these giant stars – enough to begin to make statistical samples and maps. HOBYS will use all five Herschel imaging bands for 126 hours to make images of up to 13 different massive-star-forming regions.


The Rosette Nebula is situated just over 5,000 light years away and is 100 light years across. It is shown here in an optical image by Robert Gendler. You can see it through a small telescope in the constellation of Monoceros. Inside the nebula lies NGC 2244, a cluster of bright, young O stars. You can see them sweeping out a hole in the centre of the nebula. Ultraviolet radiation from these stars makes the surrounding nebula to glow.

At the bottom of this post is a image showing how the optical and Herschel far-infrared images correlate. You can see how Herschel is seeing the much cooler material, farther out from the centre than you see in the optical image. The Herschel image is made up of three of the five Herschel wavebands (70, 160, 250 microns) making up the blue, green and red colour-channels.  It has the look of a gathering storm, or perhaps crashing waves. It is a spectacular image and I’m surprise that more has not been made of it.

You can download Sylvain Bontemp’s HOBYS talk as a PDF, which features many more images. Including a great set of RCW120, a sampling is shown here. If you’re into the science stuff, I’d suggest taking a look at lots of the talks, which can all be found here.




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