{"id":1342,"date":"2007-08-08T07:07:41","date_gmt":"2007-08-08T14:07:41","guid":{"rendered":"http:\/\/capnbob.us\/blog\/2007\/08\/08\/large-exoplanet-discovered-by-lowell-astronomers\/"},"modified":"2007-08-08T11:26:58","modified_gmt":"2007-08-08T18:26:58","slug":"large-exoplanet-discovered-by-lowell-astronomers","status":"publish","type":"post","link":"http:\/\/capnbob.us\/blog\/2007\/08\/08\/large-exoplanet-discovered-by-lowell-astronomers\/","title":{"rendered":"Large Exoplanet Discovered by Lowell Astronomers"},"content":{"rendered":"

\"tres-4.jpg\"<\/a>For several years, Damsel and I have been contributing members of Lowell Observatory<\/a> on Mars Hill<\/a> near Flagstaff, Arizona<\/a>. We occasionally visit them and always enjoy the museum and tours.<\/p>\n

Recently, Lowell Astronomers made a discovery of a very large, but low-density planet, orbiting a distant star. The planet should be smaller and more compact, according to physics, but it is a nebulous, oversized lightweight ball.<\/p>\n

Image above courtesy Lowell Observatory: Artist conception of TrES-4 and it’s host star. Click on the thumbnail image to view the high-resolution artwork.<\/strong>
\n<\/em>
\nFrom Lowell Observatory:<\/p>\n

FOR IMMEDIATE RELEASE<\/a><\/p>\n

August 6, 2007<\/strong><\/p>\n

Largest Transiting Extrasolar Planet Found Around A Distant Star<\/h4>\n

Flagstaff, Ariz.\u00e2\u20ac\u201c An international team of astronomers with the Trans-atlantic Exoplanet Survey announce today the discovery of TrES-4, a new extrasolar planet in the constellation of Hercules. The new planet was identified by astronomers looking for transiting planets \u00e2\u20ac\u201c that is, planets that pass in front of their home star \u00e2\u20ac\u201c using a network of small automated telescopes in Arizona, California, and the Canary Islands. TrES-4 was discovered less than half a degree (about the size of the full Moon) from the team\u00e2\u20ac\u2122s third planet, TrES-3.<\/p>\n

“TrES-4 is the largest known exoplanet,” said Georgi Mandushev, Lowell Observatory astronomer and the lead author of the paper announcing the discovery. “It is about 70 percent bigger than Jupiter, the Solar System\u00e2\u20ac\u2122s largest planet, but less massive, making it a planet of extremely low density. Its mean density is only about 0.2 grams per cubic centimeter, or about the density of balsa wood! And because of the planet\u00e2\u20ac\u2122s relatively weak pull on its upper atmosphere, some of the atmosphere probably escapes in a comet-like tail.”<\/p>\n

The new planet TrES-4 was first noticed by Lowell Observatory’s Planet Search Survey Telescope (PSST), set up and operated by Edward Dunham and Georgi Mandushev. The Sleuth telescope, maintained by David Charbonneau (CfA) and Francis O’Donovan (Caltech), at Caltech’s Palomar Observatory also observed transits of TrES-4, confirming the initial detections. TrES-4 is about 1400 light years away and orbits its host star in three and a half days. Being only about 4.5 million miles from its home star, the planet is also very hot, about 1,600 Kelvin or 2,300 degrees Fahrenheit.<\/p>\n

“TrES-4 appears to be something of a theoretical problem,\u00e2\u20ac\u009d said Edward Dunham, Lowell Observatory Instrument Scientist. “It is larger relative to its mass than current models of superheated giant planets can presently explain. Problems are good, though, since we learn new things by solving them.”<\/p>\n

\u00e2\u20ac\u0153We continue to be surprised by how relatively large these giant planets can be,\u00e2\u20ac\u009d adds Francis O\u00e2\u20ac\u2122Donovan, a graduate student in astronomy at the California Institute of Technology who operates one of the TrES telescopes. \u00e2\u20ac\u0153 But if we can explain the sizes of these bloated planets in their harsh environments, it may help us understand better our own Solar System planets and their formation.\u00e2\u20ac\u009d<\/p>\n

By definition, a transiting planet passes directly between the Earth and the star, blocking some of the star\u00e2\u20ac\u2122s light and causing a slight drop in its brightness. To look for transits, the small telescopes are automated to take wide-field timed exposures of the clear skies on as many nights as possible. When observations are completed for a particular field \u00e2\u20ac\u201c usually over an approximate two-month period \u00e2\u20ac\u201c astronomers measure very precisely the light from every star in the field in order to detect the possible signature of a transiting planet. “TrES-4 blocks off about one percent of the light of the star as it passes in front of it,” said Mandushev. “With our telescopes and observing techniques, we can measure this tiny drop in the star’s brightness and deduce the presence of a planet there.”<\/p>\n

Not only is the planet TrES-4 mysterious and intriguing, but so is its host star cataloged as GSC 02620-00648. Georgi Mandushev explains: \u00e2\u20ac\u0153The host star of TrES-4 appears to be about the same age as our Sun, but because it is more massive, it has evolved much faster. It has become what astronomers call a \u00e2\u20ac\u02dcsubgiant\u00e2\u20ac\u2122, or a star that has exhausted all of its hydrogen fuel in the core and is on its way of becoming a \u00e2\u20ac\u02dcred giant\u00e2\u20ac\u2122, a huge, cool red star like Arcturus or Aldebaran.\u00e2\u20ac\u009d<\/p>\n

In order to help confirm they had found a planet, G\u00c3\u00a1sp\u00c3\u00a1r Bakos of the Hungarian Automated Telescope Network (HATNet) and Harvard’s Guillermo Torres switched from the 10-centimeter TrES telescopes to one of the 10-meter telescopes at the W. M. Keck Observatory on the summit of Mauna Kea, Hawaii. Using this giant telescope, they confirmed that the TrES team had indeed found a new planet. In order to measure accurately the size and other properties of TrES-4, astronomers also made follow up observations with bigger telescopes at Lowell Observatory and Fred L. Whipple Observatory in Arizona.<\/p>\n

The authors of the paper “TrES-4: A Transiting Hot Jupiter of Very Low Density”, accepted for publication in the Astrophysical Journal, are: Georgi Mandushev and Edward Dunham of Lowell Observatory; Francis T. O\u00e2\u20ac\u2122Donovan and Lynne Hillenbrand of the California Institute of Technology; David Charbonneau, Guillermo Torres, David Latham, G\u00c3\u00a1sp\u00c3\u00a1r Bakos, Alessandro Sozzetti, and Jos\u00c3\u00a9 Fern\u00c3\u00a1ndez of the Harvard-Smithsonian Center for Astrophysics; Mark Everett and Gilbert Esquerdo of the Planetary Science Institute; Markus Rabus and Juan Belmonte of Instituto de Astrof\u00c3\u00adsica de Canarias in Tenerife, Spain; and Timothy Brown of the Las Cumbres Observatory Global Telescope.\n<\/p><\/blockquote>\n

Read a related article at space.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

For several years, Damsel and I have been contributing members of Lowell Observatory on Mars Hill near Flagstaff, Arizona. We occasionally visit them and always enjoy...<\/p>\n","protected":false},"author":190,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32,30],"tags":[],"class_list":["post-1342","post","type-post","status-publish","format-standard","hentry","category-astronomy","category-science"],"_links":{"self":[{"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/posts\/1342","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/users\/190"}],"replies":[{"embeddable":true,"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/comments?post=1342"}],"version-history":[{"count":0,"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/posts\/1342\/revisions"}],"wp:attachment":[{"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/media?parent=1342"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/categories?post=1342"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/capnbob.us\/blog\/wp-json\/wp\/v2\/tags?post=1342"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}