NASA | STScI | HubbleSite | 2015 Nov 05
[c]Using NASA's Hubble Space Telescope to conduct a "cosmic archaeological dig" at the very heart of our Milky Way galaxy, astronomers have uncovered the blueprints of our galaxy's early construction phase.
White Dwarf Stars in the Milky Way Bulge - Credit: NASA, ESA,
A. Calamida and K. Sahu (STScI), and the SWEEPS Science Team; A. Fujii[/c][hr][/hr]
Peering deep into the Milky Way's crowded central hub of stars, Hubble researchers have uncovered for the first time a population of ancient white dwarfs — smoldering remnants of once-vibrant stars that inhabited the core. Finding these relics at last can yield clues to how our galaxy was built, long before Earth and our sun formed.
The observations are the deepest, most detailed study of the galaxy's foundational city structure — its vast central bulge that lies in the middle of a pancake-shaped disk of stars, where our solar system dwells.
As with any archaeological relic, the white dwarfs contain the history of a bygone era. They contain information about the stars that existed about 12 billion years ago that burned out to form the white dwarfs. As these dying embers of once-radiant stars cool, they serve as multi-billion-year-old time pieces that tell astronomers about the Milky Way's groundbreaking years.
An analysis of the Hubble data supports the idea that the Milky Way's bulge formed first and that its stellar inhabitants were born very quickly — in less than roughly 2 billion years. The rest of the galaxy's sprawling disk of second- and third-generation stars grew more slowly in the suburbs, encircling the central bulge like the brim of a giant sombrero. ...
New insights on the Galactic Bulge Initial Mass Function - A. Calamida et al
- Astrophysical Journal 810(1):8 (2015 Sep 01) DOI: 10.1088/0004-637X/810/1/8
arXiv.org > astro-ph > arXiv:1505.07128 > 26 May 2015 (v1), 23 Jul 2015 (v2)
- Astrophysical Journal 790(2):164 (2014 Aug 01) DOI: 10.1088/0004-637X/790/2/164
arXiv.org > astro-ph > arXiv:1406.6451 > 25 Jun 2014
