ALMA | NRAO | NAOJ | ESO | 2017 Nov 28
Earliest phase of star formation ever observed in highly hostile environmentAt the center of our galaxy, in the immediate vicinity of its supermassive black hole, is a region wracked by powerful tidal forces and bathed in intense ultraviolet light and X-ray radiation. These harsh conditions, astronomers surmise, do not favor star formation, especially low-mass stars like our Sun. Surprisingly, new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) suggest otherwise.
ALMA has revealed the telltale signs of eleven low-mass stars forming perilously close — within three light-years — to the Milky Way’s supermassive black hole, known to astronomers as Sagittarius A* (Sgr A*). At this distance, tidal forces driven by the supermassive black hole should be energetic enough to rip apart clouds of dust and gas before they can form stars.
The presence of these newly discovered protostars (the formative stage between a dense cloud of gas and a young, shining star) suggests that the conditions necessary to birth low-mass stars may exist even in one of the most turbulent regions of our galaxy and possibly in similar locales throughout the Universe.
“Despite all odds, we see the best evidence yet that low-mass stars are forming startlingly close to the supermassive black hole at the center of the Milky Way,” said Farhad Yusef-Zadeh, an astronomer at Northwestern University in Evanston, Illinois, and lead author on the paper. “This is a genuinely surprising result and one that demonstrates just how robust star formation can be, even in the most unlikely of places.”
The ALMA data also suggest that these protostars are about 6,000 years old. “This is important because it is the earliest phase of star formation we have found in this highly hostile environment,” Yusef-Zadeh said. ...
ALMA Detection of Bipolar Outflows: Evidence for Low-mass Star Formation within 1 pc of Sgr A* - F. Yusef-Zadeh et al
- Astrophysical Journal Letters 850(2):L30 (2017 Dec 01) DOI: 10.3847/2041-8213/aa96a2