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Scientists Find Distant Extrasolar Planet With Atmosphere

Posted by chrisd on from the unique-delicate-snowflakes dept.

MurthyDN writes "The New York Times (Free Registration, man) has an article which says 'The Hubble Space Telescope has detected an extensive atmosphere of hydrogen enveloping and escaping from a newfound planet of a distant star, scientists reported yesterday. The discovery comes as no surprise, astronomers say, but is important nonetheless as apparent confirmation that the extrasolar planets observed so far not only are much like the solar system's Jupiter in size but also are similarly huge gaseous bodies.'"

16 comments

  1. Let's hope by jsse · · Score: 0, Offtopic

    it doesn't has any oil repository.

    Or it'd be declared Evil Planet any time soon.

  2. Deja vu all over again by infernow · · Score: 1

    Roto-Rooter Man said it first, but I agree:
    Dupe.
    The link's different, but the story's the same.
    Guess the /. editors just can't resist "free registration [and so forth]" statements. ^_^

    --

    that that is is that that is not is not

  3. Old news by barakn · · Score: 4, Informative

    This was posted way back on March 13 here. There are links that don't require the intrusive NY Times registration. They are Spaceflightnow and Nature

    --
    "I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
  4. Can you imagine what kind of weather it would have by geoswan · · Score: 1
    Can you imagine what kind of weather it would have?

    It would be receiving much more energy from its primary. Much more significant tides, too. The storms on this "Hot Jupiter" would make our Jupiter's Great Red Spot look like a spit in a bucket.

    (If it comes from a star other than the Sun, would you still call it "insolation"?)

  5. Thanks, but I'm not interested... by Randolpho · · Score: 0, Redundant

    ... until they find a rocky extra-solar planet, I'm not really interested. It's always Gas Giant, or Brown Dwarf, blah, blah, blah.

    Gimme a ST class M and I'll suddently get really friggin' interested.

    --
    "Times have not become more violent. They have just become more televised."
    -Marilyn Manson
  6. Hot Jupiter could lose entire atmosphere? by geoswan · · Score: 1
    Hot Jupiter could lose entire atmosphere?

    IANAPhysicist, but is seems to me there is an implication of this suggestion that the articles don'e mention.

    Short version: Losing all that mass will boost "hot jupiter" to a higher orbit. Wouldn't a "hot jupiter" become a merely "warm jupiter" before it lost its entire atmosphere?

    This is the same phenomenon that stripped out the Hydrogen and Helium from the Earth's atmosphere. The individual gas molecules in a planet's atmosphere, have a range of velocities -- depending on their temperature and pressure. Those molecules that random collisions to the extreme upper range of velocities can acheive escape velocity for that planet.

    The rate at which the planet loses gas depends on how hot the atmosphere is. Our own "cold" Jupiter would be losing some gas to this phenomenon too.

    But this "hot jupiter" is losing 10,000 tons a second. Jupiter is 318 times the mass of the Earth, and this "hot jupiter" is, according to the article, 2/3 of that. Again, according to the speculation mentioned in the article, it may lose all its gas, and be reduced to a cinder 10 times the mass of the Earth.

    In other words it is going to lose 95% of its mass.

    May I suggest more gas will reach escape velocity and leave from the hot side of the planet than the cold side?

    For every action there is an equal and opposite reaction. If the overall vector of the escaping gas is towards HD 209458, then it will be slowly pushing "Hot Jupiter" away from HD 209458.

    May I suggest that a "Hot Jupiter", ejecting 10,000 tons of gas per second is going to boost itself to a higher orbit, and cool enough to be a merely "Warm Jupiter", before it loses its entire atmosphere?

    1. Re:Hot Jupiter could lose entire atmosphere? by CheshireCatCO · · Score: 1

      That actually depends. If the planet were spinning rapidly, like Jupiter or Saturn, the planet would probably be pretty nearly isothermal. There is some doubt on that point, though, since planets this close to their primaries are likely tidally locked (in a 1:1 spin-orbit resonance), or at least in some low-order resonance (a la Mercury).

      (Also, if it is spinning rapidly and NOT isothermal, you'll still get the bulk of the escape occuring off to one side of the planet-star line. It takes a while for an atmosphere to heat to it's maximum daily temperature. Which is why noon is seldom the hottest part of the day.)

      Even if it isn't spinning rapidly, the heat could easily be well-distributed. Venus's temperature is pretty nearly constant across the planet, and it spins excurciatingly slowly.

      Still, interesting idea. I should run the numbers through on that one.

  7. Hot Jupiter moves out by geoswan · · Score: 1
    HD 209458 is roughly similar to Sol. What would have been the effect of a "hot jupiter" boosting itself to a higher orbit in the early Solar System?

    Bode's law: Tidal forces influenced the smaller planet's orbits to be in harmony with the real Jupiter. The same thing would happen if there were a hot jupiter in an inner orbin, wouldn't it?

    And, as "hot jupiter" slowly boosted itself to the orbit of a merely "warm jupiter", would these smaller planets move outward too?

    They aren't ejecting 90% of their mass?

    No, that is not right. At some point in their history, they were 95% of their Hydrogen and Helium too. But, with their small mass, they would have lost their H and He more quickly.

    Anyhow, what happens to you, if you are a ball of rock, in a stable orbit, when a big, "hot jupiter" slowly bears down on you?

    1. Re:Hot Jupiter moves out by CheshireCatCO · · Score: 1

      What do you mean by "harmony"? And Bode's law (as I've always seen it) doesn't work.

      A hot Jupiter would have destroyed/removed any smaller inner planets as it migrated in. So there's no real issue there.

    2. Re:Hot Jupiter moves out by geoswan · · Score: 1
      Well, I looked up your web-page, so I think I ought to be prepared to defer to you. Maybe I mis-spoke. Pluto, and those other recently discovered big Kuiper Belt objects? Aren't their orbits all 1.5 times that of Neptune? That is what I meant by harmony. Bode's law, there you have me. I couldn't restate it. I thought it merely described how the orbits of the Sun's smaller satellites were synchronized with Jupiter.

      I visited your web-site, and looked at your talk about Pluto and Charon. I saw that your summary for your colleagues stated that the Gas giants were believed to move inwards. But I didn't quite follow the mechanism. Was this just due to friction with the gas surrounding the infant sun?

    3. Re:Hot Jupiter moves out by CheshireCatCO · · Score: 1

      Ah, the term you want is "resonance". The simplist kind of resonance is a "mean motion" resonance wherein the bodies have orbital periods which are small-integer ratios. (3:2 for Pluto/Neptune, for instance.) The planets do not, in general, have orbtial resonances with each other. The fact that Pluto is in resonance with Neptune is, to some, a good reason to not call it a planet. In order to get into resonace, usually one of the bodies needs to be migrating. In Neptune's case, outward.

      (The Titus-Bode law, often simply called Bode's law -- which kind of slights poor Titus -- says that the planet's orbits lie in specific plays given by an exponential formula. It was fitted to the then-known planets, but failed increasingly miserably for the subsequently discovered planets. Interestingly, though, simulations have shown that planets do tend to space out exponentially. They don't follow a nice formula, but the distances between each does seem to increase in that general fashion.)

      Hot Jupiters migrated inwards. I've never thought about what would happen if they captured a terrestrial planet into resonance as the move, but any such capture would have to be inside of the jovian planet. Making such a planet REALLY hot once the hot Jupiter parked itself. I'm a bit dubious about whether you could capture a planet in such migration, though. The jovan planet migration timescales that I see tossed about (for the hot Jupiter; ignore Uranus and Neptune for now) is fairly short, tens to hundreds of thousands of years, usually. To capture something in a resonance, you have to sort of creep up on it. If you move to fast, the resonace sweeps right over the body and soon the hot Jupiter gets to close and either absorbs the planet or ejects it.

      The usual mechanism for hot Jupiter migrations is disk torques, actually. A massive prot-stellar disk well feel the giant planets. In return, the disk pulls back on the planet. If the torques don't balance out, the planet migrates. (The other popular mechanism is scattering a lot of small bodies out of the system. I'm a bit more skeptical of this mechanism because you have scatter a LOT of small bodies to make it work.)