University of Arizona astronomers have actually recognized 5 examples of a new class of outstanding system. They’re not rather galaxies and just exist in seclusion.
The new outstanding systems include just young, blue stars, which are dispersed in an irregular pattern and appear to exist in unexpected seclusion from any prospective moms and dad galaxy.
The outstanding systems — which astronomers state appear through a telescope as “blue blobs” and have to do with the size of small dwarf galaxies — lie within the fairly neighboring Virgo galaxy cluster. The 5 systems are separated from any prospective moms and dad galaxies by over 300,000 light years sometimes, making it challenging to recognize their origins.
The astronomers discovered the new systems after another research study group, led by the Netherlands Institute for Radio Astronomy’s Elizabeth Adams, assembled a brochure of neighboring gas clouds, supplying a list of prospective websites of new galaxies. Once that brochure was released, a number of research study groups, consisting of one led by UArizona associate astronomy teacher David Sand, began trying to find stars that might be connected with those gas clouds.
The gas clouds were believed to be connected with our own galaxy, and the majority of of them most likely are, however when the very first collection of stars, called SECCO1, was found, astronomers recognized that it was not near the Milky Way at all, however rather in the Virgo cluster, which is much further away however still really neighboring in the scale of deep space.
SECCO1 was one of the really uncommon “blue blobs,” stated Michael Jones, a postdoctoral fellow in the UArizona Steward Observatory and lead author of a research study that explains the new outstanding systems. Jones provided the findings, which Sand co-authored, throughout the 240th American Astronomical Society conference in Pasadena, California, Wednesday.
“It’s a lesson in the unexpected,” Jones stated. “When you’re looking for things, you’re not necessarily going to find the thing you’re looking for, but you might find something else very interesting.”
The group got their observations from the Hubble Space Telescope, the Very Large Array telescope in New Mexico and the Very Large Telescope in Chile. Study co-author Michele Bellazzini, with the Istituto Nazionale di Astrofisica in Italy, led the analysis of the information from Very Large Telescope and has actually sent a buddy paper concentrating on that information.
Together, the group found out that the majority of of the stars in each system are really blue and really young which they include really little atomic hydrogen gas. This is substantial since star development starts with atomic hydrogen gas, which ultimately progresses into thick clouds of molecular hydrogen gas prior to forming into stars.
“We observed that most of the systems lack atomic gas, but that doesn’t mean there isn’t molecular gas,” Jones stated. “In fact, there must be some molecular gas because they are still forming stars. The existence of mostly young stars and little gas signals that these systems must have lost their gas recently.”
The mix of blue stars and absence of gas was unforeseen, as was a absence of older stars in the systems. Most galaxies have older stars, which astronomers describe as being “red and dead.”
“Stars that are born red are lower mass and therefore live longer than blue stars, which burn fast and die young, so old red stars are usually the last ones left living,” Jones stated. “And they’re dead because they don’t have any more gas with which to form new stars. These blue stars are like an oasis in the desert, basically.”
The truth that the new outstanding systems are plentiful in metals mean how they may have formed.
“To astronomers, metals are any element heavier than helium,” Jones stated. “This tells us that these stellar systems formed from gas that was stripped from a big galaxy, because how metals are built up is by many repeated episodes of star formation, and you only really get that in a big galaxy.”
There are 2 primary methods gas can be removed from a galaxy. The initially is tidal removing, which happens when 2 huge galaxies go by each other and gravitationally tear away gas and stars.
The other is what’s called ram pressure removing.
“This is like if you belly flop into a swimming pool,” Jones stated. “When a galaxy belly flops into a cluster that is full of hot gas, then its gas gets forced out behind it. That’s the mechanism that we think we’re seeing here to create these objects.”
The group chooses the ram pressure removing description since in order for the blue blobs to have actually ended up being as separated as they are, they should have been moving really rapidly, and the speed of tidal removing is low compared to ram pressure removing.
Astronomers anticipate that a person day these systems will ultimately divide off into specific clusters of stars and expanded throughout the bigger galaxy cluster.
What scientists have actually found out feeds into the bigger “story of recycling of gas and stars in the universe,” Sand stated. “We think that this belly flopping process changes a lot of spiral galaxies into elliptical galaxies on some level, so learning more about the general process teaches us more about galaxy formation.”