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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 featured here changes its appearance noticeably in just a few weeks. Discovered over 200 years ago and subsequently cataloged as NGC 2261, the remarkable nebula is named for Edwin Hubble , who studied it early last century. Fitting, perhaps, the featured image was taken by another namesake of Hubble: the Space Telescope . 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 the Unicorn ( Monocerotis ). The 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 .
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| Date | November 8, 2017 |
|---|---|
| Credit | Image Credit: Hubble , NASA , ESA ; Data: Mark Clampin ( NASA's GSFC ); Processing & License: Judy Schmidt |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |