Friday, November 21, 2008

Another Image of an Exoplanet


Click photo to enlarge. Credit: NASA, ESA, P. Kalas, J. Graham, E. Chiang, E. Kite (University of California, Berkeley), M. Clampin (NASA Goddard Space Flight Center), M. Fitzgerald (Lawrence Livermore National Laboratory), and K. Stapelfeldt and J. Krist (NASA Jet Propulsion Laboratory)
Yet another photo of an exoplanet - this one by the Hubble Space Telescope of a planet circling Fomalhaut 25 light years from Earth in the Piscis Australis constellation.. This is the first visible light photo (the previous photos of planets circling HR 8799 used infrared). The planet, Fomalhaut b, is estimated to less than three times Jupiter's mass and orbiting 10.7 billion miles (roughly 115 AUs) out from Fomalhaut; by comparison Pluto is 39.5 AUs from our Sun. A large dust ring surrounds Fomalhaut, and astronomers theorized that since the ring was offset from the star, with a sharp inner edge - evidence that pointed to a planet circling the star gravitationally affecting the ring. Fomalhaut b is a billion times dimmer than the star is orbits, so the work of finding the planet was demanding, but after several years of determined work, the team of astronomers met with success - the first visible light photo of an exoplanet. The hunt for exoplanets is moving in exciting directions.

Reference:

"Hubble Directly Observes A Planet Orbiting Another Star." Science News. ScienceDaily. 13 Nov. 2008. Web. 21 Nov. 2008. <http://www.sciencedaily.com/releases/2008/11/081113151456.htm>.

Thursday, November 20, 2008

First confirmed images of exoplanets

Gemini and Keck observatory astronomers, using adaptive optics, have taken the first photos of confirmed exoplanets. Readers may recall the First Picture of an Extrasolar Planet! post Oct 3, also from Gemini Observatory - but that one is yet to be confirmed to be a planet. Three planets were confirmed. The planets in the photo to the right, taken by the Gemini Observatory, are two super Jupiters circling the star HR 8799 located 130 light-years away in the Pegasus constellation. The planets are circling 40 and 70 AUs from the central star. Astronomers at the Keck II Observatory discovered the third planet, circling 25 AUs away. HR 8799 is a very young star about 1.5x the mass of the Sun, and 5x brighter. The planets were probably formed 60 million years ago, far too young for life. But in the future...

Which raises an interesting thought. Far into the Earth's future, whatever sentient life form is the dominant species at the time, may have to abandon the Earth as the Sun expands and boils away the Earth's atmosphere and oceans. The planet may have to be abandoned - by then if there are any Earth-sized planets or Earth-sized moons circling the gas giants of HR 8799, they will be old enough to be hospitable for life. Future Earthlings may have to abandon this solar system for another. It would be probably easiest to colonize/terraform a planet that is ready for life, but on which life has yet to establish itself or has yet to firmly establish itself. That way the Earthlings can form the planet to their needs. This would, thus, have to begin some time before the Earth needs to be abandoned. 130 light-years is quite a distance away, but for a technologically advanced civilization that is desperate, very desperate, it could be done. Even if it was by robots including robotic ships that carried suspended genetic material to seed not only Earth life, but whoever the sentient life form is (we hope it will still be humans).

References:

"Gemini Releases Historic Discovery Image of Planetary 'First Family.'" Gemni Observatory. 13 Nov. 2008. Web. 20 Nov. 2008. <http://www.gemini.edu/threeplanetspr>.


"First Picture of Likely Planet around Sun-like Star." Gemini Observatory. 15 Sept. 2008. Web. 5 Oct. 2008. <http://www.gemini.edu/node/11126>.

"Planetary First Family Images." Gemini Observatory. 13 Nov. 2008. Web. 20 Nov. 2008. <http://www.gemini.edu/node/11150>.