V838 Mon
From Slackerpedia Galactica
What sort of star name is V838 Mon? Well, it's better than GSC 04822-00039 or USNO-A2.0 0825-03833116 - how it was known before its famous 2002 outburst.
It made the Slackerpedia Galactica show (SG #3.0 show notes) as well as the Astronomy Picture of the Day (3 Nov 2006) because it had a huge double outburst in 2002 and the Hubble Space Telescope has been taking some pictures of it ever since. Let's see you get that kind of response to a temper tantrum.
Now about that name ... check out star naming conventions to understand that this star is in the constellation Monoceros. The V means it's a variable star, and the 838 means it was the 838th variable catalogued within Monoceros.
About the light echo
The light echo is caused by energy from the eruption interacting with dust surrounding the star. The light photons are absorbed by the dust grains, which are on the order of tens to hundreds of nanometers in size and usually needle shaped. The dust re-emits the photon in another, random direction. But it keeps some of its energy, making the new photon less energetic, thus cooler and more red.
The interstellar medium dust came from eruptions of some type in its past. Each of those eruptions dispersed dust into the interstellar medium around the star. As the energy from this recent outburst moves through that dust it lights it up for us to see.
The echo'd light reaches us later, in this case months to years later, than the original outburst light because it had to travel extra distance to hit the dust and then bounce off it to eventually reach the Earth.
External Links
- The SA video podcast about V838 Mon with pics and animation
- SG 3.0 Transcript of the V838 Mon skit
- V838 Mon at Wikipedia
- V838 Mon Variable Star of the Month article from the AAVSO. Good background, but theory is a little dated.
