Researchers discover star orbiting a 'medium-sized' black hole

Jan 05, 2006

University of Iowa researchers have found a star orbiting a "medium-sized" black hole -- about 1,000 times more massive than the sun -- in the nearby starburst galaxy M82, a development that may help explain how medium-sized black holes form and evolve, according to a paper to be published in the Jan. 5 issue of Science Express, the online version of the journal Science.

Philip Kaaret, associate professor in the UI College of Liberal Arts and Sciences Department of Physics and Astronomy, made the discovery indirectly, by detecting modulations in X-rays produced by the black hole. His associates in the work were assistant professor Cornelia Lang and student Melanie Simet, a senior from Cedar Falls, Iowa.

"We discovered that the X-rays from the black hole get repeatedly brighter and dimmer every 62 days," he said. "This told us that the companion star orbiting around the black hole makes one orbit every 62 days. This, in turn, told us that the companion star has to be a giant star -- a phase in the evolution of a star when it becomes extremely bloated."

Kaaret said that the discovery may help confirm the existence of a class of black holes having a mass between 100 and 10,000 times that of the sun. That would make the objects larger than black holes produced by the collapse of a single normal star and smaller than the supermassive black holes found at the centers of galaxies.

"The discovery also explains why this black hole is so bright in X-rays. It's because the black hole can pull gas directly off from the outer layers of the giant star," Kaaret said.

The UI researchers, who used an x-ray telescope called the "Proportional Counter Array on NASA's Rossi X-Ray Timing Explorer," note that their discovery will await validation by new observations to be made with the Proportional Counter Array and other X-ray telescopes.

"This first discovery proves our technique, and we hope to make more discoveries with new X-ray observations of other black holes," Kaaret said.

Source: University of Iowa

Explore further: The Large Synoptic Survey Telescope: Unlocking the secrets of dark matter and dark energy

Related Stories

How researchers listen for gravitational waves

May 28, 2015

A century ago, Albert Einstein postulated the existence of gravitational waves in his General Theory of Relativity. But until now, these distortions of space-time have remained stubbornly hidden from direct ...

How spacetime is built by quantum entanglement

May 27, 2015

A collaboration of physicists and a mathematician has made a significant step toward unifying general relativity and quantum mechanics by explaining how spacetime emerges from quantum entanglement in a more ...

Scientists one step closer to mimicking gamma-ray bursts

May 27, 2015

Using ever more energetic lasers, Lawrence Livermore researchers have produced a record high number of electron-positron pairs, opening exciting opportunities to study extreme astrophysical processes, such ...

Hubble video shows shock collision inside black hole jet

May 27, 2015

When you're blasting though space at more than 98 percent of the speed of light, you may need driver's insurance. Astronomers have discovered for the first time a rear-end collision between two high-speed ...

A solar eclipse sheds light on physics

May 26, 2015

On 29 May 1919, a shadow dance took place over the Caribbean which was to make history: While the new moon covered the blazingly bright disk of the Sun, astronomers around Arthur Stanley Eddington measured ...

Recommended for you

What was here before the solar system?

May 29, 2015

The solar system is old. Like, dial-up-fax-machine-old. 4.6 billion years to be specific. The solar system has nothing on the universe. It's been around for 13.8 billion years, give or take a few hundred ...

What is lunar regolith?

May 29, 2015

When you're walking around on soft ground, do you notice how your feet leave impressions? Perhaps you've tracked some of the looser earth in your yard into the house on occasion? If you were to pick up some ...

Herschel's hunt for filaments in the Milky Way

May 29, 2015

Observations with ESA's Herschel space observatory have revealed that our Galaxy is threaded with filamentary structures on every length scale. From nearby clouds hosting tangles of filaments a few light-years ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.