APOD: 2000 June 29 - Galactic Centre Starscape (original) (raw)

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.

2000 June 29

Galactic Centre Starscape
Credit: ESA/ISO, CAM, S. Ganesh (PRL, IAP), A. Omont (IAP),ISOGAL Team

Explanation: Thirty thousand light-years distant, beyond themajestic dust clouds of the constellation Sagittarius, lies the centre of our Milky Way Galaxy. Hidden from optical view by the dust, theGalactic Centre region is a relatively unexplored starscape. Butinfrared light can more easily penetrate the dust andthis recently releasedInfrared Space Observatory (ISO) mosaic, together with other similar images, shows about 100,000 previously unseen stars of the Milky Way's central regions. Huge obscuring dust clouds still seem to crowd the area especially in the left part of the infrared picture. Marked by the white circle, the centre itself is missing from the mosaic because it is so bright that it would saturate ISO's sensitive camera. The starsare mostly evolvedred giants, intrinsically cool, large, bright stars that have swollen after exhausting their central supply of hydrogen fuel. The detailed properties of theredgiant stars can bevery revealingas these stars contribute to the interstellar gas and dust clouds, enriching their galactic environment withcarbon and other elements. Their motions also trace the mass distribution in the Galactic Centre and may support the idea that our Galaxy grew byswallowing smaller, nearby galaxies.

Tomorrow's picture: Gamma-ray Wine

Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris.Specific rights apply.
A service of: LHEA atNASA/GSFC
& Michigan Tech. U.