Hubble camera finds huge star clusters.They could be the Arnold Schwarzeneggers of star clusters star cluster, a group of stars near each other in space and resembling each other in certain characteristics that suggest a common origin for the group. Stars in the same cluster move at the same rate and in the same direction. Two types of clusters can be distinguished—open clusters, also called galactic clusters because of their wide distribution in our galaxy (the Milky Way), and globular clusters.. When the Hubble Space Telescope peered into the center of an oddly shaped galaxy called Arp (Address Resolution Protocol) A TCP/IP protocol used to obtain a node's physical address. A client station broadcasts an ARP request onto the network with the IP address of the target node it wishes to communicate with, and the node with that address responds by sending back its physical address so that packets can be transmitted. ARP returns the layer 2 address for a layer 3 address. 220, it imaged six densely packed clusters of stars -- the largest star-packed regions ever observed by a telescope. Ten times larger and thousands of times more luminous than the elderly, densely star-packed regions that surround our Milky Way, bigger and brighter than the young, giant clusters that Hubble found in the elliptical galaxy NGC 1275 (SN: 4/6/91, p.218; 1/25/92, p.52), the youthful star clusters in Arp 220 likely emerged after a violent collision, report Edward Shaya and Dan Dowling of the University of Maryland in College Park. The researchers suspect that two spiral galaxies collied to form Arp 220; star clusters could arise from the dust and gas unleashed in such a merger. In 1983, NASA's Infrared Astronomy infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and buildings on the earth to distant galaxies, emit infrared (IR) radiation. The study of such radiation from celestial objects is of particular importance for several reasons. Satellite revealed that Arp 220 is one of the brightest of about a dozen galaxies that emit most of their light in the infrared. Since then, scientists have debated the source of the brightness. Shaya, who presented the new findings this week at a press briefing in Washington, D.C., says it now appears that the newly discovered star clusters account for about half the galaxy's luminosity luminosity, in astronomy, the rate at which energy of all types is radiated by an object in all directions. A star's luminosity depends on its size and its temperature, varying as the square of the radius and the fourth power of the absolute surface temperature. The sun is a medium-sized star with a luminosity of 3.8×1033 ergs per sec. The luminosities of other stars are commonly expressed in terms of the sun's luminosity., with the rest coming from a compact source that Hubble has seen at the center of the galaxy. He estimates that the clusters are about 20 million years old, radiate a billiontimes the total energy output of the sun and contain many massive, short-lived stars that may soon explode as supernovas. The giant clusters may last only a few hundred million more years before tidal forces at the galaxy's center rip them apart. |
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