Latest Accretion disc Stories

2005-06-06 17:17:55

ITHACA, N.Y. -- The office that astronomer Lei Hao shares with her fellow research associates on the first floor of the Space Sciences Building at Cornell University is tidy and organized. But Hao has been thinking a lot lately about dust. Actually, she's recently found a great deal of it. And she's thrilled. The dust in question is between 0.88 billion and 2.4 billion light years away from Hao's office, in galaxies scientists classify as active galactic nuclei (AGNs). By confirming that...

2005-04-06 08:20:00

RAS -- New supercomputer simulations may help explain periodic bursts of light emitted by compact binary star systems. Cataclysmic variables are binary systems that consist of a white dwarf and a normal star. The dense white dwarf drags material from its companion star, creating an accretion disc of matter around itself, and a hotspot develops where the gas stream from the star crashes into the accretion disc. On Wednesday 6th April at the RAS National Astronomy Meeting in Birmingham, Dr...

2005-01-11 14:20:00

San Diego, CA -- Astronomers Jon Miller (Harvard-Smithsonian Center for Astrophysics) and Jeroen Homan (MIT) have seen evidence of hot iron gas riding a ripple in spacetime around a black hole. This spacetime wave, if confirmed, would represent a new phenomenon that goes beyond Einstein's general relativity. These observations confirm one important theory about how a black hole's extreme gravity can stretch light. The data also paint an intriguing image of how a spinning black hole can drag...

Latest Accretion disc Reference Libraries

2004-10-19 04:45:44

Cosmogony -- Cosmogony is the study of the origins of celestial objects. It is most commonly used to refer to the study of the origin of the solar system. Currently, the most widely accepted theory is that the solar system was formed roughly 5 billion years ago with the collapse of a nebula of gas and dust, likely caused by shock waves generated by a nearby supernova. The solar system would have formed as a member of a star cluster, now long-since dispersed throughout the Milky Way over...

2004-10-19 04:45:43

X-ray Burster -- X-ray bursters are a class of binary stars which are luminous in X-rays. They contain a neutron star and a low-mass companion star. The companion fills its Roche lobe and therefore the neutron star is accreting matter from it. The inflowing gas forms an accretion disk around the neutron star. Sometimes X-ray bursters show a sudden increase in their X-ray luminosity, called X-ray burst. All properties of the X-ray bursts can be explained assuming that they result from...

2004-10-19 04:45:42

Seyfert Galaxy -- Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. The light from the central nucleus varies in less than a year, which implies that the emitting region must be less than one light year across. They are named for the astronomer Carl Seyfert, who studied them extensively in the 1940s. They are a subclass of active galactic nuclei....

2004-10-19 04:45:41

Microquasar -- Microquasars are smaller cousins of quasars. They are named after quasars, as they have some common characteristics: strong and variable radio emission often seen as radio jets, and an accretion disk surrounding a black hole. In quasars, the black hole is supermassive (millions of solar masses) as in microquasars, the black hole mass is a few solar masses. In microquasars, the accreted mass comes from a normal star and the accretion disk is very luminous in optical regions...

2004-10-19 04:45:41

Accretion Disk -- An accretion disk is a structure formed by material falling into a gravitational source. Conservation of angular momentum requires that, as a large cloud of material collapses inward, any small rotation it may have will increase. Centrifugal force causes the rotating cloud to collapse into a disk, and tidal effects will tend to align this disk's rotation with the rotation of the gravitational source in the center. Friction between the particles of the disk generates heat...

More Articles (5 articles) »
Word of the Day
  • A murmuring sound; a rushing or whistling sound, like that of the wind; a deep sigh.
  • A gentle breeze; a waft; a breath.
  • Any rumor that engages general attention.
  • A cant or whining mode of speaking, especially in preaching or praying; the chant or recitative characteristic of the old Presbyterians in Scotland.
  • To make a rushing, whistling, or sighing sound; emit a hollow murmur; murmur or sigh like the wind.
  • To breathe in or as in sleep.
  • To utter in a whining or monotonous tone.
According to the OED, from the 16th century, this word is 'almost exclusively Scots and northern dialect until adopted in general literary use in the 19th.'