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Space Science

Probing an 'Invisible' Exoplanet's Atmosphere 28

Posted by Soulskill
from the seeing-what-we-can-see dept.
astroengine writes "To study the atmospheres of planets beyond the solar system, astronomers have had two choices: pick one that flies across the face of its parent star relative to Earth's perspective (an event known as a transit), or wait for a new generation of more sensitive space telescopes that can directly capture the planet's faint light. Now, there's a third option. Using a cryogenically-cooled infrared detector on a telescope in Chile, astronomers ferreted out beams of light coming directly from Tau Boötis b, a massive planet about 50 light-years from Earth."
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Probing an 'Invisible' Exoplanet's Atmosphere

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  • "Third option"? (Score:5, Interesting)

    by K. S. Kyosuke (729550) on Wednesday June 27, 2012 @05:09PM (#40472151)
    Why does the "third option" sound so suspiciously similar to the second one? If VLT is not one of the "new generation of more sensitive space telescopes", then I'll eat my shoes.
    • Re:"Third option"? (Score:5, Informative)

      by CanHasDIY (1672858) on Wednesday June 27, 2012 @05:15PM (#40472213) Homepage Journal

      Why does the "third option" sound so suspiciously similar to the second one? If VLT is not one of the "new generation of more sensitive space telescopes", then I'll eat my shoes.

      I believe by "space telescopes," the summary writer was specifically referring to telescopes deployed in space.

      • by Hatta (162192)

        I hope OP wears leather shoes.

        • by sco08y (615665)

          I hope OP wears leather shoes.

          I'm hoping that the OP wears cake shoes, just on the principle that if I ever found myself having to eat my shoes, I'd rather they were delicious. And that I was wearing socks, and that I had scrubbed my feet that morning.

    • by jdastrup (1075795)
      Because only have 1 option to overcome doesn't sounds nearly as good as overcoming 2 obstacles.
    • Possibly because the telescope in Chile was a retrofitted existing telescope, as opposed to a new telescope.

  • Why is this a third option?`Doesn't it belong to b)?

    • by rolfeb (1218438)

      Option b) is imaging just the light from the planet (which we can't currently do).

      It looks like option c) is imaging the combined light from the star and planet, but using the doppler shifting of the planet's light as it rotates around the star to work out the planet's contribution.

    • by PPH (736903)
      I sense the presence of CowboyNeal at work here.
    • Re: (Score:2, Funny)

      by Anonymous Coward

      Because Chile != space.

      Seriously, how hard is this? Please join K. S. Kyosuke for a shoe luncheon.

      • by mcgrew (92797) *

        Because Chile != space

        "Alien" != "someone from outer space".

        Alien vs Lucifer [slashdot.org]

        Harley is an alien. Rather than being from Betelguise as one might suppose, or even Guilford, Harley was from Peru.

  • In orbit you would get the cryogenic part for free, and no matter how clear and dry is the atmosphere in Chile, is no match for no atmosphere at all in orbit. But I suppose that a new telescope in space would fit into the 2nd option.
  • Better source (Score:4, Informative)

    by phme (1501991) on Wednesday June 27, 2012 @06:00PM (#40472623)

    discovery.com, really? From ESO's press release (http://www.eso.org/public/news/eso1227/):

    The team used the CRIRES instrument on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile. They combined high quality infrared observations (at wavelengths around 2.3 microns) [At infrared wavelengths, the parent star emits less light than in the optical regime, so this is a wavelength regime favorable for separating out the dim planet’s signal.] with a clever new trick to tease out the weak signal of the planet from the much stronger one from the parent star.

    This method uses the velocity of the planet in orbit around its parent star to distinguish its radiation from that of the star and also from features coming from the Earth’s atmosphere. The same team of astronomers tested this technique before on a transiting planet, measuring its orbital velocity during its crossing of the stellar disc.

    Lead author of the study Matteo Brogi (Leiden Observatory, the Netherlands) explains: “Thanks to the high quality observations provided by the VLT and CRIRES we were able to study the spectrum of the system in much more detail than has been possible before. Only about 0.01% of the light we see comes from the planet, and the rest from the star, so this was not easy”.

    The majority of planets around other stars were discovered by their gravitational effects on their parent stars, which limits the information that can be gleaned about their mass: they only allow a lower limit to be calculated for a planet’s mass. The new technique pioneered here is much more powerful. Seeing the planet’s light directly has allowed the astronomers to measure the angle of the planet’s orbit and hence work out its mass precisely. By tracing the changes in the planet’s motion as it orbits its star, the team has determined reliably for the first time that Tau Boötis b orbits its host star at an angle of 44 degrees and has a mass six times that of the planet Jupiter in our own Solar System.
    [...]
    As well as detecting the glow of the atmosphere and measuring Tau Boötis b’s mass, the team has probed its atmosphere and measured the amount of carbon monoxide present, as well as the temperature at different altitudes by means of a comparison between the observations and theoretical models. A surprising result from this work was that the new observations indicated an atmosphere with a temperature that falls higher up. This result is the exact opposite of the temperature inversion — an increase in temperature with height — found for other hot Jupiter exoplanets

  • by PPH (736903)

    Shake yer Boötis!

  • Scientists not only learned just how massive Tau Boo is -- roughly six times the size of Jupiter

    There are two other planets in this system, it seems: Mu Boo and Na Boo.

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