From: owner-chakram-refugees-digest@smoe.org (chakram-refugees-digest) To: chakram-refugees-digest@smoe.org Subject: chakram-refugees-digest V6 #80 Reply-To: chakram-refugees@smoe.org Sender: owner-chakram-refugees-digest@smoe.org Errors-To: owner-chakram-refugees-digest@smoe.org Precedence: bulk chakram-refugees-digest Wednesday, April 12 2006 Volume 06 : Number 080 Today's Subjects: ----------------- [chakram-refugees] OT: NY Times Article on Planet Xena ["bookdaft" Subject: [chakram-refugees] OT: NY Times Article on Planet Xena This was reported in today's New York Times Science News section (for those who care, they are talking about Planet Xena's albedo): April 11, 2006 10th Planet Appears Barely Larger Than Pluto By KENNETH CHANG The 10th planet turns out to be barely larger than Pluto, a new photograph by the Hubble Space Telescope shows. The object  still officially unnamed but currently tagged with the designation 2003 UB313 and nicknamed Xena  covered an area only 1.5 pixels across in the digital image taken by Hubble, but that was enough to extract the diameter: 1,490 miles, give or take 60 miles. Pluto has a diameter of 1,422 miles. While small, 2003 UB313 is surprisingly bright, reflecting 86 percent of the light that hits it. "It's just crazy," said Michael E. Brown, a professor of planetary sciences at the California Institute of Technology who discovered 2003 UB313 in January 2005 and who also led the analysis of the Hubble image. "We were shocked how bright it was." Pluto, already considered bright, reflects 60 percent of its incoming light. Only Enceladus, one of the moons of Saturn, is more reflective among objects in the solar system. Astronomers recently discovered that Enceladus has geysers of water shooting out of its south pole; the water, turned to ice crystals, give the surface a sheen of freshly fallen snow. That is unlikely to be the reason for 2003 UB313's brightness; it is too far away  nine billion miles  and too cold  probably minus-400 degrees Fahrenheit. Instead, Dr. Brown speculates the bright surface is a result of a highly eccentric orbit. When it was closer to the Sun, coming as close as 3.5 billion miles, 2003 UB313 was warmer and probably had a thin atmosphere of methane. As it moved away, the air likely froze and fell to the ground, giving 2003 UB313 a bright layer of ice, Dr. Brown said. A previous estimate by researchers at the University of Bonn had put the diameter at 1,900 miles. But that calculation, based on measurements taken from the ground, had a greater uncertainty of 250 miles. Another Hubble observation later this year should pin down the orbit of a moon orbiting 2003 UB313 and that would give the planet's mass. Astronomers have not decided whether to officially call 2003 UB313 a planet or demote Pluto. In recent years, many astronomers have said Pluto should just regarded as a member of the Kuiper Belt, a ring of icy bodies beyond the orbit of Neptune. Given that 2003 UB313 is almost a twin of Pluto, at least in terms of size, the ultimate fate of terminology for the two distant objects could well be the same. Copyright 2006 The New York Times Company ========================================================= This has been a message to the chakram-refugees list. To unsubscribe, send a message to majordomo@smoe.org with "unsubscribe chakram-refugees" in the message body. Contact meth@smoe.org with any questions or problems. ========================================================= ------------------------------ End of chakram-refugees-digest V6 #80 *************************************