APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
NGC 2261: Hubble's Variable Nebula
Explanation: What causes Hubble's Variable Nebula to vary? The unusual nebula pictured above changes its appearance noticeably in just a few weeks. Discovered over 200 years ago and subsequently cataloged as NGC 2661, the remarkable nebula is named for Edwin Hubble , who studied it earlier this century. Hubble's Variable Nebula is a reflection nebula made of gas and fine dust fanning out from the star R Monocerotis. The faint nebula is about one light-year across and lies about 2500 light-years away towards the constellation of Monocerotis . A leading variability explanation for Hubble's Variable Nebula holds that dense knots of opaque dust pass close to R Mon and cast moving shadows onto the reflecting dust seen in the rest of the nebula.
| Date | October 20, 1999 |
|---|---|
| Credit |
Credit: William Sparks (STScI), Sylvia Baggett (STScI) et al., & the Hubble Heritage Team (AURA/ STScI/ NASA) |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |