Astronomers find runaway galaxies & Visible Light From An Exoplanet Detected for first time

Astronomers find runaway galaxies

We know of about two dozen runaway stars, and have even found one runaway star cluster escaping its galaxy forever. Now, astronomers have spotted 11 runaway galaxies that have been flung out of their homes to wander the void of intergalactic space.

"These galaxies are facing a lonely future, exiled from the galaxy clusters they used to live in," said astronomer Igor Chilingarian (Harvard-Smithsonian Center for Astrophysics/Moscow State University). Chilingarian is the lead author of the study, which is appearing in the journal Science.

An object is a runaway if it's moving faster than escape velocity, which means it will depart its home never to return. In the case of a runaway star, that speed is more than a million miles per hour (500 km/s). A runaway galaxy has to race even faster, traveling at up to 6 million miles per hour (3,000 km/s).

[link to phys.org]

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Visible Light From An Exoplanet Detected

The planet examined in the study, 51 Pegasi b, is actually somewhat famous; in 1995 it was the first confirmed exoplanet to be discovered orbiting around a star quite similar to our own Sun. But at 50 light years away, we still have no conception of the planet’s appearance.

Using the HARPS instrument on the ESO 3.6-meter telescope at the La Sille Observatory, the researchers examined the unique spectrum of visible light coming from the star system of 51 Pegasi. They then detected a much fainter copy of this light spectrum, realizing that this signature was the light reflected off of 51 Pegasi b. “It’s like 10,000 times fainter than the light of the star,” Martin explains. By removing the star’s light spectrum and other various sources of noise, the team can isolate just the light bouncing off the exoplanet.

[link to www.popsci.com]