ALMA discovers infant stars surprisingly near galaxy's supermassive black hole

ALMA discovers infant stars surprisingly near galaxy's supermassive black hole
November 28, 2017

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An ALMA image of the center of the Milky Way galaxy showing the location of 11 young protostars within about 3 light-years of our galaxy's supermassive black hole. The lines indicate the direction of the bipolar lobes created by high-velocity jets from the protostars. The illustrated star in the middle of the image indicates the location of Sagittarius A*, the 4 million solar mass supermassive black hole at the center of our galaxy. The next image is a zoom-in to one of the protostars. Credit: ALMA (ESO/NAOJ/NRAO), Yusef-Zadeh et al.; B. Saxton (NRAO/AUI/NSF)
At 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.




Read more at: https://phys.org/news/2017-11-alma-infant-stars-surprisingly-galaxy.html#jCp
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the paper:
http://iopscience.iop.org/article/10.3847/2041-8213/aa96a2/meta

ALMA Detection of Bipolar Outflows: Evidence for Low-mass Star Formation within 1 pc of Sgr A*


Abstract
We report the discovery of 11 bipolar outflows within a projected distance of 1 pc from Sgr A* based on deep ALMA observations of 13CO, H30α, and SiO (5−4) lines with subarcsecond and ~1.3 km s−1 resolutions. These unambiguous signatures of young protostars manifest as approaching and receding lobes of dense gas swept up by the jets created during the formation and early evolution of stars. The lobe masses and momentum transfer rates are consistent with young protostellar outflows found throughout the disk of the Galaxy. The mean dynamical age of the outflow population is estimated to be

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years. The rate of star formation is ~5 × 10−4

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yr−1 assuming a mean stellar mass of ~0.3

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. This discovery provides evidence that star formation is taking place within clouds surprisingly close to Sgr A*, perhaps due to events that compress the host cloud, creating condensations with sufficient self-gravity to resist tidal disruption by Sgr A*. Low-mass star formation over the past few billion years at this level would contribute significantly to the stellar mass budget in the central few parsecs of the Galaxy. The presence of many dense clumps of molecular material within 1 pc of Sgr A* suggests that star formation could take place in the immediate vicinity of supermassive black holes in the nuclei of external galaxies.

 

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Very interesting and thank you for posting.
Alex

 

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