{"id":11074,"date":"2013-10-20T01:00:59","date_gmt":"2013-10-20T11:00:59","guid":{"rendered":"http:\/\/darkerview.com\/wordpress\/?p=11074"},"modified":"2013-10-19T10:52:48","modified_gmt":"2013-10-19T20:52:48","slug":"watery-asteroid-discovered-in-dying-star-points-to-habitable-exoplanets","status":"publish","type":"post","link":"https:\/\/darkerview.com\/wordpress\/?p=11074","title":{"rendered":"Watery Asteroid Discovered in Dying Star Points to Habitable Exoplanets"},"content":{"rendered":"

W. M. Keck Observatory press release<\/a>…<\/p>\n

Astronomers have found the shattered remains of an asteroid that contained huge amounts of water orbiting an exhausted star, or white dwarf. This suggests that the star GD 61 and its planetary system \u2013 located about 150 light years away and at the end of its life \u2013 had the potential to contain Earth-like exoplanets.<\/p>\n

The new research findings used data collected from NASA\u2019s Hubble Space Telescope, both of W. M. Keck Observatory\u2019s Keck I and Keck II telescopes, as well NASA\u2019s FUSE telescope, and are reported today in the journal Science. <\/p>\n

\"Watery<\/a>
Artist impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star GD 61. Credit: Copyright Mark A. Garlick, space-art.co.uk, University of Warwick and University of Cambridge.<\/figcaption><\/figure>This is the first time both water and a rocky surface – two key ingredients for habitable planets – have been found together beyond our solar system.<\/p>\n

Earth is essentially a “dry” planet, with only 0.02% of its mass as surface water, meaning oceans came long after it had formed; most likely when water-rich asteroids in the solar system crashed into our planet.<\/p>\n

The asteroid analyzed is composed of 26% water mass, very similar to Ceres, the largest asteroid in the main belt of our solar system. Both are vastly more water-rich compared with Earth. <\/p>\n

The new discovery shows the same water delivery system could have occurred in this distant, dying star\u2019s solar system \u2013 as latest evidence points to it containing a similar type of water-rich asteroid that would have first brought water to Earth. <\/p>\n

Astronomers at the Universities of Cambridge and Warwick say this is the first \u201creliable evidence\u201d for water-rich, rocky planetary material in any extrasolar planetary system. <\/p>\n

The scientists, led by Cambridge\u2019s Institute of Astronomy\u2019s Jay Farihi, describe it as a “look into our future”. Six billion years from now, alien astronomers studying the rocky remains around our burned out sun might reach the same conclusion: terrestrial planets once circled our parent star. <\/p>\n

All rocky planets form from the accumulation of asteroids, growing until full size, so asteroids are essentially the ‘building blocks’ of planets. <\/p>\n

“The finding of water in a large asteroid means the building blocks of habitable planets existed \u2013 and maybe still exist \u2013 in the GD 61 system, and likely also around a substantial number of similar parent stars,” Farihi said.<\/p>\n

“These water-rich building blocks, and the terrestrial planets they build, may in fact be common \u2013 a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces,” Farihi said. “Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system.”<\/p>\n

The detected water most likely came from a minor planet, at least 90 km in diameter but probably much larger, that once orbited the GD 61 star before it became a white dwarf around 200 million years ago. <\/p>\n

Previous and current astronomical observations have measured the size and density of exoplanets, but not their composition, because conventional work was only done on planets orbiting living stars. <\/p>\n

But the only way to see what a distant planet is made of is to take it apart, say the researchers, and nature does this in a dying white dwarf system through its extreme gravitational pull \u2013 sucking in and shredding the surrounding material.<\/p>\n

This debris was chemically analyzed using powerful spectrograph instruments installed on the Keck I and Keck II telescopes to detect a range of elemental abundances in the white dwarf\u2019s contaminated atmosphere, including magnesium, silicon and iron, which, together with oxygen are the main components of rocks. <\/p>\n

By calculating the number of these elements relative to oxygen, the researchers were able to predict how much oxygen should be in the atmosphere of the white dwarf \u2013 but they found significantly more oxygen than if there were only rocks. <\/p>\n

“This oxygen excess can be carried by either water or carbon, and in this star there is virtually no carbon \u2013 indicating there must have been substantial water,” said co-author Boris G\u00e4nsicke, from the University of Warwick. <\/p>\n

“This also rules out comets, which are rich in both water and carbon compounds, so we knew we were looking at a rocky asteroid with substantial water content \u2013 perhaps in the form of subsurface ice \u2013 like the asteroids we know in our solar system such as Ceres,” G\u00e4nsicke said.<\/p>\n

The team used the Cosmic Origins Spectrograph onboard Hubble to obtain precise oxygen levels in the white dwarf\u2019s debris, with chemical analysis computed by team member Detlev Koester from the University of Kiel. <\/p>\n

The planetary bodies such as these asteroids that fall into and pollute this dying star \u2013 which, in its heyday, was three times heavier than our sun \u2013 also reveal that giant exoplanets probably still exist in this remote and withering system.<\/p>\n

“In order for the asteroids to pass sufficiently close to the white dwarf to be shredded, then eaten, they must be perturbed from the asteroid belt \u2013 essentially pushed \u2013 by a massive object like a giant planet,” said Farihi.<\/p>\n

“These asteroids tell us that the GD 61 system had \u2013 or still has \u2013 rocky, terrestrial planets, and the way they pollute the white dwarf tells us that giant planets probably still exist there,” he said. “This supports the idea that the star originally had a full complement of terrestrial planets, and probably gas giant planets, orbiting it \u2013 a complex system similar to our own.” <\/p>\n","protected":false},"excerpt":{"rendered":"

W. M. Keck Observatory press release… Astronomers have found the shattered remains of an asteroid that contained huge amounts of water orbiting an exhausted star, or white dwarf. This suggests that the star GD 61 and its planetary system \u2013 located about 150 light years away and at the end of its life \u2013 had … Continue reading “Watery Asteroid Discovered in Dying Star Points to Habitable Exoplanets”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[9],"tags":[56,50,68,885],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11074"}],"collection":[{"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=11074"}],"version-history":[{"count":2,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11074\/revisions"}],"predecessor-version":[{"id":11077,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/11074\/revisions\/11077"}],"wp:attachment":[{"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=11074"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=11074"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/darkerview.com\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=11074"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}