[meteorite-list] Comet Hartley 2: The 'Weird' Comet
http://www.space.com/20033-comet-hartley-2.html?cmpid=514648 Hartley 2: The 'Weird' Comet Elizabeth Howell space.com March 1, 2013 Comet Hartley 2, officially known as 103P/Hartley, visits the inner solar system about every 6.5 years. The comet was discovered by an amateur astronomer in 1986 and received a visit from a NASA mission, Epoxi, in 2010. It is expected to return in April 2017. Although the comet is a frequent visitor to the sun, it's still a very active small body. NASA has called Hartley 2 a "weird little comet", and one NASA astronomer characterized Hartley 2 as "a hyperactive little comet, spewing out more water than most other comets its size." Scientists studying the small comet have raised the possibility that more comets behave the same way, especially if they carry plenty of carbon dioxide or monoxide in their composition. Hartley 2's visit by Epoxi also revealed some strange scientific discoveries, such as "glittering blocks" on either end of the comet. Caught by quality control Hartley 2 is named after its discoverer, Malcolm Hartley, an amateur astronomer working for the Siding Spring Observatory in New South Wales, Australia. He has held several roles at the facility over the years, but in March 1986 he was a quality controller examining the accuracy of images taken by a Schmidt telescope on site. On March 16 of that year, he saw a strange smudge on a photographic glass plate. "Back then, the observations came in as negatives - stars and other objects in the sky appeared black on a clear background," said Hartley in an interview published by NASA in 2011. "I noticed a dark haze around a trail. Trails indicate something that is travelling fast through the sky, but asteroids don't have a haze. So I thought it might be a comet." His find was confirmed by the International Astronomical Union's minor planet center a few days after the discovery. Hartley actually went on to discover at least 10 more comets during his career, until Siding Spring changed the Schmidt telescope he used to perform spectroscopy in 2002. Hartley's namesake returns to the inner solar system near Earth about once every 6.5 years. Although it's nowhere near as bright as say, Halley's Comet at its finest, Hartley 2's frequent return makes it a valuable object for astronomers seeking to understand how the sun alters these dirty snowballs during repeat trips near the sun. A last-minute mission switch Interest in Comet Hartley 2 picked up in 2007, when NASA made a last-minute decision to divert the Deep Impact mission in the comet's direction. The agency originally planned to target Comet Boethin, but that periodic comet vanished from view before Deep Impact could get there. "We were confident we could find the comet, and we were astonished when it wasn't there," stated the University of Hawaii's Karen Meech, one of the mission's co-investigators, in a 2007 press release. The scientists guessed that the comet broke up into pieces too small to see from Earth. While Hartley 2 was a promising target, NASA said the drawback to visiting that comet over Boethin was it would take two years longer to bring the spacecraft close by. Because instruments can degrade over time, this initially made Boethin the primary choice. Deep Impact had already launched in 2005 to first swing by Comet Tempel and eject an impactor into the comet before heading by Earth again in 2007, redirecting its trajectory and launching towards Hartley 2. The mission's change to Hartley 2 renewed scientific interest in the comet. Other observatories performed more detailed studies of Hartley 2, including the orbiting NASA Spitzer Space Telescope. Researchers using the observatory examined Hartley 2's nucleus and rate of mass loss that occurs every time it passes near the sun. They estimated that Hartley 2 could last about 700 more years about 100 more trips around the sun - before it breaks up. Carbon dioxide and 'glittering blocks' Before reaching Hartley 2, Deep Impact was renamed Epoxi to reflect a search for Earth-size exoplanets around five stars. It took three laps of the sun before Epoxi could get close to Hartley - a trip of 1.6 billion miles (about 18 times the distance between the Earth and the sun.) Epoxi made its closest approach to Hartley 2 in November 2010, looking to understand more about the comet's interior. It passed as close as 431 miles (694 kilometers) from the comet's surface. Rather than sending a probe into Hartley 2, Epoxi monitored poofs of gas emanating from the comet's surface and surrounding it. It also hunted for water ice on the comet. Studying the oddball comet up close revealed that outbursts on the comet do not happen uniformly. Jets from the comet, powered by carbon dioxide, were more populous on either side of Hartley 2 than at the middle. The "waist" of the comet instead had jets with water vapor, with only a little car
[meteorite-list] Comet Hartley 2 Leaves a Bumpy Trail (WISE)
http://www.jpl.nasa.gov/news/news.cfm?release=2011-210 Comet Hartley 2 Leaves a Bumpy Trail Jet Propulsion Laboratory July 14, 2011 New findings from NEOWISE, the asteroid- and comet-hunting portion of NASA's Wide-field Infrared Survey Explorer mission, show that comet Hartley 2 leaves a pebbly trail as it laps the sun, dotted with grains as big as golf balls. Previously, NASA's EPOXI mission, which flew by the comet on Nov. 4, 2010, found golf ball- to basketball-sized fluffy ice particles streaming off comet Hartley 2. NEOWISE data show that the golf ball-sized chunks survive farther away from the comet than previously known, winding up in Hartley 2's trail of debris. The NEOWISE team determined the size of these particles by looking at how far they deviated from the trail. Larger particles are less likely to be pushed away from the trail by radiation pressure from the sun. The observations also show that the comet is still actively ejecting carbon dioxide gas at a distance of 2.3 astronomical units from the sun, which is farther away from the sun than where EPOXI detected carbon dioxide jets streaming from the comet. An astronomical unit is the average distance between Earth and the sun. "We were surprised that carbon dioxide plays a significant role in comet Hartley 2's activity when it's farther away from the sun," said James Bauer, the lead author of a new paper on the result in the Astrophysical Journal. An abstract of the scientific paper is online at http://arxiv.org/abs/1107.2637 , with the option of downloading a full PDF. JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise , http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise . Whitney Clavin (818) 354-4673 Jet Propulsion Laboratory, Pasadena, Calif. whitney.cla...@jpl.nasa.gov 2011-210 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] comet hartley
that is quite a timely coincidence surely the meaning for those images are known within the respective Native American communities? Jim Original Message From: gmh...@htn.net Date: Nov 4, 2010 16:03 To: , Subject: Re: [meteorite-list] comet hartley Hey All, Anyone notice the similarities of the "dumbell tektite comet" http://www.nasa.gov/mission_pages/epoxi/epoxi-1-20101104.html that Jim commented on and some of the petroglyphs that Thomas has on his web page (halfway down his list of images here: http://www.photoblog.com/GreyDX/ ) Maybe those Indians were a little more sophisticated than most give them credit for. Maybe the BLM have some of their early telescopes hidden away from public view for government use! ;-) Best regards, Greg Greg Hupe The Hupe Collection NaturesVault (eBay) gmh...@htn.net www.LunarRock.com IMCA 3163 Click here for my current eBay auctions: http://search.ebay.com/_W0QQsassZnaturesvault - Original Message - From: To: Sent: Thursday, November 04, 2010 11:36 AM Subject: [meteorite-list] comet hartley > Thanks Jeff > what a cool looking dumbell tektite comet---excellent job nasa > > close-up image > > http://www.nasa.gov/mission_pages/epoxi/epoxi-1-20101104.html > __ > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.864 / Virus Database: 271.1.1/3236 - Release Date: 11/03/10 15:34:00 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] comet hartley
Hey All, Anyone notice the similarities of the "dumbell tektite comet" http://www.nasa.gov/mission_pages/epoxi/epoxi-1-20101104.html that Jim commented on and some of the petroglyphs that Thomas has on his web page (halfway down his list of images here: http://www.photoblog.com/GreyDX/ ) Maybe those Indians were a little more sophisticated than most give them credit for. Maybe the BLM have some of their early telescopes hidden away from public view for government use! ;-) Best regards, Greg Greg Hupe The Hupe Collection NaturesVault (eBay) gmh...@htn.net www.LunarRock.com IMCA 3163 Click here for my current eBay auctions: http://search.ebay.com/_W0QQsassZnaturesvault - Original Message - From: To: Sent: Thursday, November 04, 2010 11:36 AM Subject: [meteorite-list] comet hartley Thanks Jeff what a cool looking dumbell tektite comet---excellent job nasa close-up image http://www.nasa.gov/mission_pages/epoxi/epoxi-1-20101104.html __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.864 / Virus Database: 271.1.1/3236 - Release Date: 11/03/10 15:34:00 __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] comet hartley
Thanks Jeff what a cool looking dumbell tektite comet---excellent job nasa close-up image http://www.nasa.gov/mission_pages/epoxi/epoxi-1-20101104.html __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] Comet Hartley 2 - Hartley 103/P
Hello Observers and Meteorite Lovers, Last week I captured some images of comet hartley 2 and I wanted to share them with the group(s). You can see a single frame and an animated gif representing 45 minutes of flight here: http://www.mikesastrophotos.com/comets/comet-hartley-2-103phartley/ Thanks, Mike __ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
