Brown Dwarf “Missing Links” Found
Astronomers at the Joint Astronomy Center in Hawaii are reporting that they have found examples of so-called “missing links” that fill the gap between Jupiter-class extrasolar planets and the larger brown dwarfs – stars that almost happened. According to a press release, the discovery resulted from a collaboration between astronomers using the United Kingdom Infrared Telescope (UKIRT) in Hawaii and scientists associated with the Sloan Digital Sky Survey (SDSS).
According to the release, “Brown dwarfs have surface temperatures that range down from about 3,500 K (3,200°C) to 1,500K (1,200 °C). Over most of this range their appearances are similar to cool stars of the same
temperature. However, as the surface of a brown dwarf cools below 1,500 K, a dramatic chemical change takes place: large amounts of methane form,
considerably altering the appearance of the brown dwarf.”
Brown dwarfs with detectable Methane in their atmospheres have been detected previously – as have smaller, Jupiter-class planets. It is the objects in between that have eluded astronomers – until now. According the release, “the three newly discovered brown dwarfs bridge the gap between the young, warmer group and the cooler methane group. They are not identical, but form a sequence linking the warmer more star-like and the cooler more planet-like types”.
The results of this research will be published in the Astrophysical Journal.
Related Links
° Brown dwarf ‘missing link’ discovered, Joint Astronomy Center, Hilo, Hawaii
° The Missing Link: Early Methane (“T”) Dwarfs in the Sloan Digital Sky Survey, abstract, Astrophysical Journal
Background Information
° Eight Extrasolar Planets Discovered Circling Sun-like Stars, SpaceRef
° Eight New Very Low-Mass Companions to Solar-Type Stars Discovered at La Silla, ESO press release
° NASA Announces a Significant Advance in Planet Hunting, SpaceRef
° Extrasolar Planets, SpaceRef Directory
° Very Early Planetary Formation Observed in Orion?, SpaceRef
° Hubble Confirms Abundance of Protoplanetary Disks Around Newborn Stars, Space Telescope Science Institute, 1994
° Hot Jupiters and Rare Earths: Planets are common. Are we?, SpaceRef
° Six New Extrasolar Planets Discovered, SpaceRef
° Of Planetary Transits Near and Far, SpaceRef
