Cygnus X-1: Still a 'Star' After All Those Years

Aug 28, 2009
Credits: NASA/CXC

Since its discovery 45 years ago, Cygnus X-1 has been one of the most intensively studied cosmic X-ray sources. About a decade after its discovery, Cygnus X-1 secured a place in the history of astronomy when a combination of X-ray and optical observations led to the conclusion that it was a black hole, the first such identification.

The Cygnus X-1 system consists of a black hole with a mass about 10 times that of the Sun in a close orbit with a blue supergiant star with a mass of about 20 Suns. Gas flowing away from the supergiant in a fast stellar wind is focused by the black hole, and some of this gas forms a disk that spirals into the black hole. The gravitational energy release by this infalling gas powers the X-ray emission from Cygnus X-1.

Although more than a thousand scientific articles have been published on Cygnus X-1, its status as a bright and nearby black hole continues to attract the interest of scientists seeking to understand the nature of and how they affect their environment. Observations with Chandra and ESA's are especially valuable for studying the property of the stellar wind that fuels Cygnus X-1, and determining its rate of spin.

This latter research has revealed that Cygnus X-1 is spinning very slowly. This puzzling result could indicate that Cygnus X-1 may have formed in an unusual type of that somehow prevented the newly formed black hole from acquiring as much spin as other stellar black holes.

Provided by JPL/NASA (news : web)

Explore further: Exoplanet measured with remarkable precision

add to favorites email to friend print save as pdf

Related Stories

Black Hole Blows Bubble Between The Stars

Aug 11, 2005

A team of astronomers from The Netherlands and the UK has discovered a vast "jet-powered bubble" formed in the gas around a black hole in the Milky Way.

New Massive Black Hole Smashes Record

Oct 30, 2007

Using two NASA satellites, astronomers have discovered the heftiest known black hole to orbit a star. The new black hole, with a mass 24 to 33 times that of our Sun, is more massive than scientists expected ...

A new way to weigh giant black holes

Jul 16, 2008

How do you weigh the biggest black holes in the universe? One answer now comes from a completely new and independent technique that astronomers have developed using data from NASA's Chandra X-ray Observatory.

Recommended for you

A spectacular landscape of star formation

1 hour ago

This image, captured by the Wide Field Imager at ESO's La Silla Observatory in Chile, shows two dramatic star formation regions in the Milky Way. The first, on the left, is dominated by the star cluster NGC ...

Exoplanet measured with remarkable precision

Aug 19, 2014

Barely 30 years ago, the only planets astronomers had found were located right here in our own solar system. The Milky Way is chock-full of stars, millions of them similar to our own sun. Yet the tally ...

New star catalog reveals unexpected 'solar salad'

Aug 19, 2014

(Phys.org) —An Arizona State University alumnus has devised the largest catalog ever produced for stellar compositions. Called the Hypatia Catalog, after one of the first female astronomers who lived in ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

Nik_2213
not rated yet Aug 28, 2009
There's lots of scenarios that may spin-up a black-hole progenitor. What will make them spin-down ? Interaction of mag field with surrounds ?
Ashibayai
not rated yet Aug 29, 2009
Tidal deceleration.
Birger
not rated yet Aug 29, 2009
Is the visible component -the blue supergiant- the star known as HDE226868? Or am I confusing X-ray sources?
yyz
not rated yet Aug 30, 2009
@birger, yes, indeed the blue supergiant is a.k.a. HD 226868, V1367 Gyg, BD 35 3815, among many other catalog numbers :)