#STELLAR RAM PRESSURE FULL#

They expect that one day these systems will eventually split off into individual clusters of stars and spread out across the larger galaxy cluster. The scientists prefer the ram-pressure stripping explanation because in order for the blue blobs to have become as isolated as they are, they must have been moving very quickly, and the speed of tidal stripping is low compared to ram-pressure stripping. That’s the mechanism that we think we’re seeing here to create these objects,” Dr.

#STELLAR RAM PRESSURE FULL#

When a galaxy belly flops into a cluster that is full of hot gas, then its gas gets forced out behind it. “This is like if you belly flop into a swimming pool. The other is what’s known as ram-pressure stripping. The first is tidal stripping, which occurs when two big galaxies pass by each other and gravitationally tear away gas and stars. There are two main ways gas can be stripped from a galaxy. 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,” Dr. “To astronomers, metals are any element heavier than helium. The fact that the new stellar systems are abundant in metals hints at how they might have formed. These blue stars are like an oasis in the desert, basically.” “And they’re dead because they don’t have any more gas with which to form new stars. “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,” Dr. Most galaxies have older stars, which astronomers refer to as being ‘red and dead.’ The combination of blue stars and lack of gas was unexpected, as was a lack of older stars in the systems. The existence of mostly young stars and little gas signals that these systems must have lost their gas recently.” “In fact, there must be some molecular gas because they are still forming stars. “We observed that most of the systems lack atomic gas, but that doesn’t mean there isn’t molecular gas,” Dr. This is significant because star formation begins with atomic hydrogen gas, which eventually evolves into dense clouds of molecular hydrogen gas before forming into stars. The researchers also learned that the systems contain very little atomic hydrogen gas. The five systems are separated from any potential parent galaxies by over 300,000 light-years in some cases, making it challenging to identify their origins. They found that these structures contain only young, blue stars, which are distributed in an irregular pattern and seem to exist in surprising isolation from any potential parent galaxy. Jones and colleagues detected five blue stellar systems within the Virgo galaxy cluster. Jansky Very Large Array and ESO’s Very Large Telescope, Dr. Using data from the NASA/ESA Hubble Space Telescope, NSF’s Karl G. Michael Jones, a postdoctoral researcher with the Steward Observatory at the University of Arizona. “SECCO1, also known as AGC 226067, was one of the very unusual blue blobs,” said Dr. This Hubble image shows a blue stellar system.

Stellar ram pressure