Planets like Kepler-7b (left) are nicknamed "hot Jupiters" because they share characteristics with the largest planet in our solar system (right), but have a much higher surface temperature. Kepler-7b's temperature is about 1,800 degrees Fahrenheit (1,300 Kelvin). Jupiter's temperature is about -234 degrees Fahrenheit (125 Kelvin).

Image courtesy NASA/JPL-Caltech/MIT

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  • On November 27, 2001, analysis of Hubble Space Telescope data detected an atmosphere on the extrasolar planet Osiris, the first atmosphere detected on a planet outside our solar system. Osiris orbits a star in the constellation Pegasus. It is located more than 150 light years from our solar system. Osiris is a “hot Jupiter,” almost 220 times as big as Earth.
    Using sensitive instruments aboard Hubble, scientists determined that only a planet with a stable atmosphere could produce the light spectrum exhibited by Osiris. While the size and composition of Osiris is incompatible with organic life, astrophysicists discovered some familiar elements in its atmosphere: hydrogen, carbon, oxygen, and sodium.
  • Term Part of Speech Definition Encyclopedic Entry
    astrophysicist Noun

    person who studies the relationship between matter, energy, motion, and force outside the Earth's atmosphere.

    atmosphere Noun

    layers of gases surrounding a planet or other celestial body.

    Encyclopedic Entry: atmosphere
    constellation Noun

    group of stars that form a recognizable shape.

    element Noun

    chemical that cannot be separated into simpler substances.

    exhibit Noun

    display, often in a museum.

    extrasolar planet Noun

    planet outside the solar system, orbiting a star other than the sun. Also called an exoplanet.

    instrument Noun


    orbit Noun

    path of one object around a more massive object.

    organic Adjective

    composed of living or once-living material.

    solar system Noun

    the sun and the planets, asteroids, comets, and other bodies that orbit around it.

    spectrum Verb

    continuous band of material with each piece differing in small amounts from the piece before and after it.

    stable Adjective

    steady and reliable.

    star Noun

    large ball of gas and plasma that radiates energy through nuclear fusion, such as the sun.