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Astronomers find giant stream of stars running between galaxies

With large future telescopes, the researchers not only hope to discover new giant streams, they also want to zoom in on the Giant Coma Stream itself…reports Asian Lite News

An international team of researchers has discovered the largest-ever giant and extremely faint stream of stars running between galaxies.

The observations were made with University of California-Los Angeles astronomer Michael Rich’s relatively small 70-centimetre telescope in the US and using the 4.2-metre William Herschel telescope at La Palma, Spain.

After image processing, they saw an extremely faint stream more than 10 times the length of our Milky Way.

Named the Giant Coma Stream, it appeared to float in the middle of the cluster environment, not associated with any galaxy in particular, said the researchers in the paper published in the journal Astronomy & Astrophysics.

“This giant stream crossed our path by coincidence,” said lead researcher Javier Roman, associated with the University of Groningen in the Netherlands and the University of La Laguna in Spain.

“We were studying halos of stars located around large galaxies.”

The discovery of the Giant Coma Stream is remarkable because it is a rather fragile structure amid a hostile environment of mutually attracting and repelling galaxies.

“Meanwhile, we have been able to simulate such huge flows in the computer. We therefore expect to find more of them. For example, if we search with the future 39-metre ELT and when Euclid starts producing data,” said co-author Reynier Peletier from University of Groningen.

With large future telescopes, the researchers not only hope to discover new giant streams, they also want to zoom in on the Giant Coma Stream itself.

“We would love to observe individual stars in and near the stream and learn more about dark matter,” Peletier said.

The Coma Cluster is one of the best-studied clusters of galaxies. It contains thousands of galaxies at a distance of about 300 million light-years from Earth in the direction of the northern constellation Coma Berenices.

In 1933, Swiss astronomer Fritz Zwicky showed that the galaxies in the cluster move too fast if you only take the amount of visible matter into account. He figured out that there must be dark matter that keeps things together. The exact nature of dark matter is still unknown.

ALSO READ-Astronomers detect new planet orbiting Proxima Centauri

Astronomers detect new planet orbiting Proxima Centauri

Proxima b was discovered a few years ago using the HARPS instrument on ESO’s 3.6-metre telescope…reports Asian Lite News

A team of astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile have found evidence of another planet orbiting Proxima Centauri, the closest star to our Solar System.

Proxima Centauri is the closest star to the Sun, lying just over four light years away.

The newly discovered planet, named Proxima d, orbits Proxima Centauri at a distance of about four million kilometres, less than a tenth of Mercury’s distance from the Sun.

This candidate planet is the third detected in the system and the lightest yet discovered orbiting this star. At just a quarter of Earth’s mass, the planet is also one of the lightest exoplanets ever found.

These findings are published in Astronomy & Astrophysics journal.

“The discovery shows that our closest stellar neighbour seems to be packed with interesting new worlds, within reach of further study and future exploration,” said Joao Faria, a researcher at the Instituto de Astrofisica e Ciencias do Espaco, Portugal, in a statement.

Proxima d orbits between the star and the habitable zone — the area around a star where liquid water can exist at the surface of a planet — and takes just five days to complete one orbit around Proxima Centauri.

The star system is already known to host two other planets: Proxima b, a planet with a mass comparable to that of Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

Proxima b was discovered a few years ago using the HARPS instrument on ESO’s 3.6-metre telescope.

The discovery was confirmed in 2020 when scientists observed the Proxima system with a new instrument on ESO’s VLT that had greater precision, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO).

It was during these more recent VLT observations that astronomers spotted the first hints of a signal corresponding to an object with a five-day orbit. As the signal was so weak, the team had to conduct follow-up observations with ESPRESSO to confirm that it was due to a planet, and not simply a result of changes in the star itself.

“After obtaining new observations, we were able to confirm this signal as a new planet candidate,” Faria said.

At just a quarter of the mass of Earth, Proxima d is also the lightest exoplanet ever measured using the radial velocity technique, surpassing a planet recently discovered in the L 98-59 planetary system.

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