Mysterious Blue Blobs May Be Galactic ‘Stomach Bellies’, Astronomers Say

Arizona astronomers have recognized a brand new class of star system. The gathering of principally younger blue stars is seen right here utilizing the Hubble Area Telescope’s Superior Digital camera for Surveys. Credit score: Michael Jones

Astronomers on the College of Arizona have recognized 5 examples of a brand new class of star system. They aren’t fairly galaxies and so they solely exist in isolation.

The brand new star methods comprise solely younger blue stars, that are unfold out in an irregular sample and seem to exist in stunning isolation from any potential father or mother galaxy.

The star methods – which astronomers say seem by means of a telescope as “blue spots” and are in regards to the dimension of tiny dwarf galaxies – are situated within the comparatively close by Virgo galaxy cluster. All 5 methods are separated from any potential father or mother galaxy by greater than 300,000 mild years in some instances, making it troublesome to establish their origins.

Astronomers found the brand new methods after one other analysis group, led by Elizabeth Adams of the Netherlands Institute for Radio Astronomy, compiled a catalog of close by fuel clouds, offering a listing of potential websites of latest galaxies. As soon as this catalog was printed, a number of analysis teams, together with one led by UArizona affiliate astronomy professor David Sand, started trying to find stars that may be related to these fuel clouds.

The fuel clouds have been regarded as related to our personal galaxy, and most of them in all probability are, however when the primary assortment of stars, referred to as SECCO1, was found, astronomers realized that ‘it wasn’t close to the Milky Manner in any respect, however slightly within the Virgo cluster, way more distant however nonetheless very shut on the size of the universe.

SECCO1 was one of many very uncommon “blue spots,” stated Michael Jones, postdoctoral researcher on the UArizona Steward Observatory and lead writer of a research describing new star methods. Jones introduced the findings, co-authored by Sand, on the 240th assembly of the American Astronomical Society in Pasadena, Calif., on Wednesday.

“It is a lesson within the surprising,” Jones stated. “Whenever you’re on the lookout for issues, you are not essentially going to seek out the factor you are on the lookout for, however you may discover one thing else very fascinating.”

The workforce obtained their observations from the Hubble Area Telescope, the Very Giant Array Telescope in New Mexico and the Very Giant Telescope in Chile. Research co-author Michele Bellazzini, with the Istituto Nazionale di Astrofisica in Italy, led the evaluation of the Very Giant Telescope information and submitted a companion paper centered on the info.

Collectively, the workforce realized that almost all stars in every system are very blue and really younger, and comprise little or no atomic hydrogen. That is essential as a result of star formation begins with atomic hydrogen fuel, which ultimately evolves into dense clouds of molecular hydrogen fuel earlier than turning into stars.

“We noticed that almost all methods lack atomic fuel, however that does not imply there is not molecular fuel,” Jones stated. “In reality, there should be molecular fuel as a result of they’re nonetheless forming stars. The existence of principally younger stars and little fuel signifies that these methods should have misplaced their fuel not too long ago.”

The mix of blue stars and lack of fuel was surprising, as was the dearth of older stars within the methods. Most galaxies have older stars, which astronomers name “purple and lifeless.”

“Stars which can be born purple have decrease mass and due to this fact dwell longer than blue stars, which fritter away shortly and die younger, so previous purple stars are often the final ones left alive,” Jones stated. “And so they’re lifeless as a result of they’ve run out of fuel to kind new stars with. These blue stars are like an oasis within the desert, mainly.”

The truth that the brand new star methods are ample in metals signifies how they may have fashioned.

“For astronomers, metals are any factor heavier than helium,” Jones stated. “It tells us that these star methods fashioned from fuel that was extracted from a big galaxy, as a result of the way in which metals are constructed is by many repeated episodes of star formation, and you do not actually solely get that in a giant galaxy.”

There are two predominant methods to extract fuel from a galaxy. The primary is tidal stripping, which happens when two giant galaxies intersect and gravitationally pull fuel and stars aside.

The opposite is what is called piston stress suppression.

“It is like falling face down in a pool,” Jones stated. “When a galaxy stomach collapses right into a cluster stuffed with scorching fuel, its fuel is pressured out behind it. That is the mechanism we predict we see right here for creating these objects.”

The workforce prefers the ram stress stripping clarification as a result of for the blue drops to have develop into as remoted as they’re, they should be transferring in a short time and the rate of tidal stripping is low in comparison with ram stress stripping .

Astronomers anticipate that someday these methods will ultimately separate into particular person clusters of stars and unfold out into the bigger cluster of galaxies.

What the researchers realized feeds into “the bigger story of fuel and star recycling within the universe,” Sand stated. “We consider that this belly-falling course of transforms many spiral galaxies into elliptical galaxies at some stage, so studying extra in regards to the basic course of tells us extra about how galaxies kind.”

Hubble focuses on the big lenticular galaxy 1023

Extra data:
Michael G. Jones et al, Younger, Blue, and Remoted Star Programs within the Virgo Cluster. II. A brand new class of star system. arXiv:2205.01695v1 [astro-ph.GA]

Offered by the College of Arizona

Quote: Mysterious Blue Blobs May Be Galactic ‘Stomach Flops’, Astronomers Say (2022, June 16) Retrieved June 17, 2022, from galactic-belly.html

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