A glossary of_their_quarry

A glossary of_their_quarry

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  Section Name 3 MAY2013 VOL 340 SCIENCE www.sciencemag.org Gas giants more than 50 times the mass of Earth orbiting too close to their stars to be habitable. Make up 42% of confirmed planets. Example: 51 Pegasi b. Similar to a hot Jupiter in mass and prox- imity to a star, but much less dense and thus larger. Synonym: Inflated hot Jupiter. Example: HAT-P-1. Planets between 10 and 50 Earth masses orbiting close to their stars. Example: Gliese 436 b. A planet that is less massive than Neptune but shares its characteristic thick atmo- sphere of hydrogen and helium. Current detection techniques can have trouble telling them from super-Earths. Example: Kepler-11 b-f. A planet with about two to 10 times the mass of Earth. Can be hard to distinguish from a mini-Neptune. Example: Kepler-62 e and f. A planet about the mass of Earth, but not nec- essarily within its star’s habitable zone. Exam- ple: Planet orbiting Alpha Centauri Bb. A rocky planet with one to 10 times the mass of Earth, orbiting in the habitable zone of its star. Possible example: expected any time. Synonyms: Twin Earth, Goldilocks planet, Earth 2.0, Earth analog, Earth-like planet. CREDITS:(GRAPHICPHOTOSLEFTTORIGHT)NASA/APOLLO17CREW;NASA/JPL;NASA/JPL/UNIVERSITYOFARIZONA;(BOTTOM)NASA/TIMPYLE 570 –LIZZIE WADE Published by AAAS onMay3,2013www.sciencemag.orgDownloadedfrom
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  www.sciencemag.org SCIENCE VOL340 3 MAY 2013 An exoplanet orbiting a pulsar, a spinning neutron star left behind after a supernova; probably debris from the explosion, trapped by the neutron star’s strong gravity. Only a handful are known. Not habitable. Examples: PSR 1257+12 b, c, and d, the first exoplanets ever discovered back in 1992. A super-Earth covered in water— in the form of ice, oceans, or a water-vapor atmosphere, depend- ing on the planet’s proximity to the star. Example: Gliese 1214b. With orbits the shape of stretched- out ellipses, these planets can swoop through drastically different temperature zones in the course of a year. Example: HD 80606 b. CREDITS(CLOCKWISEFROMTOPLEFT):NASA/JPL-CALTECH/R.HURT/SSC;ESO/L.CALÇADA/P.DELORME/R.SAITO/VVVCONSORTIUM; NASA/JPL-CALTECH;NASA/ESA/D.AGUILAR/HARVARD-SMITHSONIANCENTERFORASTROPHYSICS;ESO/L.CALÇADA;NASA/JPL;ESA/NASA/L.CALÇADA/ESOFORSTSCL 571 A planet that orbits a binary star system and thus has two suns instead of one. Examples: Kepler-16 b, Tatooine. A planet that does not orbit a star. Astron- omers don’t know whether these wander- ing planets were ejected from star systems or formed by themselves in interstellar space. Rogue planets can be up to 13 times the mass of Jupiter; more-massive bod- ies are classified as brown dwarfs. Without stars to keep them warm, they are always frigid. Synonyms: orphan planet, homeless planet, nomad planet, free-floating planet, sub-brown dwarf. Example: CFBDSIR 2149-0403. The rocky core left behind after the gas of a hot Jupiter evaporates as a result of orbiting so close to its star. Synonym: chthonian planet, evaporated remnant core. Example: COROT-7b (suspected); HD 209458 b is in the process of evaporating. Sometimes called a failed star, a brown dwarf forms when a cloud of gas collapses but is not massive enough to ignite the fusion reactions that fuel fully formed stars. Brown dwarfs can be 13 to 75 times the mass of Jupiter. Less massive bodies are rogue planets; more mas- sive ones can sustain fusion and are thus stars. Some brown dwarfs have their own planets. Example: 2M1207. A moon orbiting an exoplanet. Some exomoons of gas giants may have molten interiors thanks to tidal heating, which could keep them warm even outside their stars’ habitable zones and make them easy to spot from afar. But so far, no exomoons have been observed. Possible example: Fomalhaut b. Published by AAAS onMay3,2013www.sciencemag.orgDownloadedfrom