A Star of Space and Film

Rollie Hawk writes "Three years ago, light from V838 Monocerotis (a star about 20,000 light years from us) reached the Earth that showed the star exploding. The more politically correct term for what happened is "stellar outburst." In the time since, images from a pulse of light released during the outburst have been arriving here on Earth. In October of 2004, Hubble captured a beautiful image of the scene with the pulse lighting up interstellar gasses that encapsulated the area around this red giant (a star 600,000 times brighter than our Sun). The release of this photo just days ago seems rather timely, as it appears that some of Hubble's funding may be cut in the near future. There is also talk of eliminating the program entirely."

Comments

Astronomy picture of the day

[Cyrgo]

Here is NASA's Astronomy picture of the day site Astronomy picture of the day with the same picture and a brief explanation (with hyperlinks).
Enjoy

Look at the entire series of HST images over time

[StupendousMan]

If you go to the HST web site, you can see an entire series of images of V838 Mon over the past three years.

http://hubblesite.org/newscenter/newsdesk/archiv e/ releases/2005/02/image/a

Although the series _appears_ to show a shell of gas expanding outwards from the star, it does not. Instead, what we see is the expanding echo of light reflecting off gas and dust in the interstellar medium, between V838 Mon and the Earth. It might help to look at a nice diagram of the "light echo" effect provided by space.com:

http://www.space.com/php/multimedia/imagedisplay /i mg_display.php?pic=light_echo_graphic_030326_02,0. jpg

The European Space Agency also has a good description of the event:

http://www.space.com/scienceastronomy/light_echo _0 30326.html

The fact that no material is actually shooting outwards into space as fast as the pictures appear to indicate -- that we are simply seeing a reflection of light as it moves through the gas cloud, like the beam of a flashlight swept through the air in a dusty room -- explains how the shell can _appear_ to expand outwards faster than light.

Star Tomography

[Nuffsaid]

A very interesting thing about this stellar outburst is the possibility to get a 3D image of the cloud surrounding the star. Images of this event taken months apart (like this sequence) show the flash of light as it expands, illuminating regions of space that form spherical shells around the star. This gives a unique insight into the actual threedimensional structure of the cloud, a bit like a CAT scan builds a 3D view from a sequence of planar 2D images. Pity we don't have (for all I know) one picture per day: it would have made a stunning movie! No to mention the scientific value...