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Exo-Planet Image Probably A Star Science News - June 28, 1999 - New data indicate that the object described last year as probably the first extrasolar planet to be imaged is more likely just a run-of-the-mill star. At a widely reported press briefing in May 1998, NASA unveiled Hubble Space Telescope images that astronomer Sue Terebey of the Extrasolar Research Corp. in Pasdena, Calif., said might show a planet born to a pair of stars 450 light-years from Earth. The images made headlines because they could go down in history as the first ever taken of a planet outside the solar system. But several astronomers recently told Science News that additional data, which Terebey presented at two meetings this month, strongly suggest that the object is too hot to be a planet. Instead, it is "almost certainly a normal reddened star," says Keith S. Noll of the Space Telescope Science Institute in Baltimore. Details appear in the June 26 issue of Science News, a weekly news magazine. Terebey told Science News that she would not talk to reporters until next month. By then, she said, she will have had time to assimilate comments from the scientists who had seen her new data and to submit a research article to a peer-reviewed journal. According to several scientists who attended her presentations, Terebey acknowledged that the spectrum she has now obtained of the faint object, dubbed TMR-1C, reveals that it does not contain water vapor, which should be present if it were a planet with a temperature lower than 2,500 K. Because water is abundant in the cosmos, its absence is a reliable indicator of a high temperature, Noll explains. Terebey presented her spectrum, taken at the Keck telescopes atop Hawaii's Mauna Kea, on June 9 at a meeting on giant planets and cool stars in Flagstaff, Ariz., and on June 17 at a Gordon Research Conference on the origin of the solar system in Henneker, N.H. According to astronomers at the two meetings, Terebey acknowledged that the spectrum could be that of a star. However, she also suggested that the object might be a failed star, known as a brown dwarf, or a planet that is warmer and possibly younger than she had first thought. Terebey showed that the spectrum of an ordinary, low-mass star, partly obscured by foreground dust, roughly matches her spectrum of TMR-1C, according to astronomers who heard her Flagstaff presentation. This "implies strongly" that TMR-1C is just a background star, says Mark S. Marley of New Mexico State University in Las Cruces, an organizer of the Flagstaff meeting. "It is a real stretch of the data to claim anything else." "In my opinion, it is a waste of time and bad science to keep pursuing this idea [of a planet] when a much simpler and more likely alternative is supported by all the evidence," says Noll. "Extrasolar planets are one of current astronomy's holy grails, and so there is strong temptation to see them where one want to see them. But in this case, the data seems to be saying quite clearly that this extrasolar planet was an illusion."
Additional Links
ExtraSolar at Spacer.Com
Radar Opens Hidden Lunar Poles Ithaca - June 3, 1999 - The hidden poles of the moon have been revealed by Cornell University and Jet Propulsion Laboratory researchers working with the radar antennas of NASA's Deep Space Network at Goldstone, Calif. The south pole image, in particular, reveals a chaotic surface, with deep craters that are in permanent shadow from the sun and which are potential repositories for water ice. |
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