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First Exoplanet To Be Seen In Color Is Blue 139

Posted by timothy from the your-eyes-are-the-color-of-hd-189733-b dept.
ananyo writes "A navy-blue world orbiting a faraway star is the first exoplanet to have its colour measured. Discovered in 2005, HD 189733 b is one of the best-studied planets outside the Solar System, orbiting a star about 19 parsecs away in the Vulpecula, or Fox, constellation. Previous efforts to observe the planet focused on the infrared light it emits — invisible to the human eye. Astronomers have now used the Hubble Space Telescope to observe the planet and its host star. Hubble's optical resolution is not high enough to actually 'see' the planet as a dot of light separate from its star, so instead, the telescope receives light from both objects that mix into a single point source. To isolate the light contribution of the planet, the researchers waited for the planet to move behind the star during its orbit, so that its light would be blocked, and looked for changes in light colour. During the eclipse, the amount of observed blue light decreased, whereas other colours remained unaffected. This indicated that the light reflected by the planet's atmosphere, blocked by the star in the eclipse, is blue."
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First Exoplanet To Be Seen In Color Is Blue More

First Exoplanet To Be Seen In Color Is Blue

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  • Suggested name of the planet (Score:5, Funny)

    by dkleinsc ( 563838 ) on Thursday July 11, 2013 @01:58PM (#44253835) Homepage

    Let's call this place "Eiffel 65".

    • Damn! The other planets are always bluer!

    • Re: (Score:1)

      by Anonymous Coward

      It's in Vulpecula.
      I wonder if it's a good place for Androsynth.

      • It's in Vulpecula.
        I wonder if it's a good place for Androsynth.

        Let's enslave some and find out. Actually, let's not and say we did. I'd rather they didn't unleash Orz into *heavy space*.

    • Blue Marble II - The sequel!

    • Re: (Score:1)

      by Anonymous Coward

      No. Let's not.

    • Re: (Score:2)

      by gmuslera ( 3436 )
      I would call it "Microsoft Windows". From this distance, you can only see a it's Blue Sky Of Death, but maybe some life (i.e. virus, worms and similar) could had evolved there.

  • Question: what atmospheric constituents? (Score:5, Interesting)

    by under_score ( 65824 ) <mishkin.berteig@com> on Thursday July 11, 2013 @02:00PM (#44253857) Homepage

    I'm curious: what are the likely elements and molecules that would cause the blue reflection?

  • Did they find the Androsynth living there?

    • Re: (Score:1)

      by Anonymous Coward

      No, but Orz is happy to *spit* hello.

  • So this planet might have a breathable atmosphere. But odds are it's more methane-based.

    Still, pretty nice we can observe a planet's color.

  • FTA

    To isolate the light contribution of the planet, Evans and his colleagues waited for the planet to move behind the star during its orbit, so that its light would be blocked, and looked for changes in light colour.

    A spectrograph on board the Hubble monitored light coming from the source, in wavelengths ranging from yellow to ultraviolet. During the eclipse, the amount of observed blue light decreased, whereas other colours remained unaffected. This indicated that the light reflected by the planet's atmo

    • Are you suggesting that the planet orbits its star at such a high speed as to produce an observable doppler shift?
      • I don't know. You tell me. I don't know what the orbital period for this planet is or the distance it orbits at. Orbital speeds are pretty fast though. Google tells me that the earth moves about 107,000 km/hr around the sun. If their instruments are sensitive enough, they might see the difference. I would also guess there is a possible gravitational redshift and lensing depending on the mass of the star and the orbital distance.

      • Certainly. We've already managed to locate a few planets based on the miniscule doppler shift of the star as it orbits its system's barycenter (our barycenter for reference varies between about 1/2 and 3 solar radii from the sun's center). In comparison the doppler shift of the planet would be massive (on an admittedly much weaker signal)

        However, it still wouldn't be an issue assuming you made your planet observation(s) immediately before/after it went behind its star - at that point its orbital velocity

      • Are you suggesting that doppler doesn't work for measuring vehicle speeds, with a lower (by many orders of magnitude) velocity relative to the observer? See: RADAR gun

    • No, I did not RTFA, but the first thought I had was; if the planet is between us and its star, we'd be "seeing" the side of the planet facing away from the star. Wouldn't it be dark? It's not like it's a binary system with another star lighting the opposite side. Since it's a gas giant, I guess there would be enough light filtering through the upper atmosphere edges to cast off some light, but overall, it seems like such a small area to glean colors from.

      • Re: (Score:3)

        by Nadaka ( 224565 )

        when a planet begins to transition behind its star, we would be seeing the bright sunward side of the planet, so the measure is still useful. We would only be seeing the full dark side of the planet when it passed in front of the parent star.

      • Yes, the colors are measured from that area.

    • The redshift used to measure the speed of objects moving away from us applies primarily to the galaxy as a whole. If you were to normalize the light received to compensate for the redshift of the galaxy as a whole, the additional velocity of the planet, being negligibly small with respect to your new frame of reference would not significantly 'redden' your results. Good question though.

    • It wouldn't be an issue assuming you made your planet observation(s) immediately before/after it went behind its star - at that point its orbital velocity would be at right angles to our line-of-sight, so no doppler shift. Plus those are the points where the planet would be the fullest, so it's the natural time to take your measurements.

  • I, for one, will be happy when Hubble is dead (Score:5, Funny)

    by Overzeetop ( 214511 ) on Thursday July 11, 2013 @02:42PM (#44254363) Journal

    I mean, look at all this time and effort we're wasting on "science" and "discovery."

    We need to get back to 16th century thinking and government funded services so my taxes can go down another $10 a paycheck. I mean, those cigarettes and premium cable TV channels aren't going to pay for themselves!

    • We need to get back to 16th century thinking and government funded services so my taxes can go down another $10 a paycheck.

      I just now calculated it, and you're right, it is about $10 per paycheck for a typical software developer income.

      It used to be that kings and noblemen would fund science. Now they fund vaccines for the poor. It used to be people funded the poor via the "poor box" at church. Now people fund science (whether they like it or not).

      The net result is, for the common person, taking religion

    • Re: (Score:2)

      by Tailhook ( 98486 )

      First, false dilemma.

      Second, taxing people that have disposable income is a lot more effective then trying to tax people that don't.

      Third, get a grip. We're discussing extra-solar planets. Not every story is another opportunity for you to exhibit your training as a malcontent.

  • Glass, people. Glass. (Score:3)

    by vikingpower ( 768921 ) on Thursday July 11, 2013 @02:42PM (#44254367) Homepage Journal
    The planet has a surface temperature of about 1000 degrees Celsius. It is scourged by 7000 km/h winds. Pieces of silica, or if you prefer: glass, are flying around at supersonic speeds. And yes, it is the silica and the glass that give the planet its blue color. We should not call it Eiffel65. We should call it Philip.

  • IANAA (Score:1)

    by Anonymous Coward

    I am not an astronomer; any chance that the coloration could be affected by something in between? For example these so called "wrinkles" that Voyager is experiencing as it exits the solar system? Just curious.

  • Units! (Score:1)

    by Anonymous Coward

    Since parsec is an antiquated unit, this planet is about 62 light years away. (or, more usefully: 2.914 quadrillion furlongs)

    Wow. I actually got to be pedantic about units and none of the units involved were metric!

    • Re: (Score:2)

      by bmk67 ( 971394 )

      Since parsec is an antiquated unit

      Since when? The parsec is a very handy unit when you're measuring distance to stars from Earth using the parallax method.

    • One parsec means a parallax of 1 arc second, so presumably 19 parsecs means a parallax of 19 arc seconds? No? OTOH, to me, last year was a heavy year, so in comparison, this year feels like a light year.

    • Re: (Score:2)

      by sFurbo ( 1361249 )
      While neither parsec or light year [wikipedia.org] are accepted for use with the SI system, the distance in parsecs can be experimentally determined up to around 1.000-2.000 parsecs, so its use can be accepted (though I assume this indicates that the distance is determined by parallax, or is extrapolated from a distance measured with parallax). Light years have no such redeeming features, and is only used because people are to lazy to use proper units, which in this case would make the distance 5.9*10^2 petameters, or 0.59

  • 19 parsecs? (Score:3)

    by plover ( 150551 ) on Thursday July 11, 2013 @02:48PM (#44254421) Homepage Journal

    In other words, it's about 1.6 Kessel Runs? But how fast is that?

  • Where are the pictures? (even if one pixel wide)

  • Several times in TFS, it says that the planet is "eclipsed" by the star. This, of course, is nonsense: the correct term is "occluded," and the event is called an occultation.

  • The planet isn't blue. The blue light that got blocked out by the host star was actually the trillions of blue LEDs that the natives use to light their cities, just because they happen to really fancy blue.

    • Re: (Score:2)

      by Livius ( 318358 )

      " blue LEDs that the natives use to light their cities"

      So, not coloured blue, just giving off blue light?

  • Vulpecula - Little Vixen, it differs slightly in connotation from the article's translation of Fox.

    • Re: (Score:2)

      by danlip ( 737336 )

      Vixen just means female fox, and the connotations you are thinking of post-date Latin by at least a millennium.

  • Fuck that shit! It's light years around here buddy!

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