Stormy Weather: Brown Dwarf Star Could Model Extra-Solar Planet Atmosphere

Article written: 13 Sep , 2011
Updated: 24 Dec , 2015
by

[/caption]Thanks to the help of the infrared camera on the 2.5m telescope at Las Campanas Observatory in Chile, astronomers are taking a very close look at a brown dwarf star named 2MASS J2139. During a recent survey they noticed something a little bit peculiar about this transitional solar system entity. Not only does it lay somewhere in-between being a dwarf star or a large planet – but it would appear to have a form of weather. Apparently there’s no place to escape clouds!

A University of Toronto-led team of astronomers had been doing a survey of nearby brown dwarfs, when they noticed that one in particular changed brightness in a matter of hours – the largest variation observed so far.

“We found that our target’s brightness changed by a whopping 30 per cent in just under eight hours,” said PhD candidate Jacqueline Radigan, lead author of a paper to be presented this week at the Extreme Solar Systems II conference in Jackson Hole, Wyoming and submitted to the Astrophysical Journal. “The best explanation is that brighter and darker patches of its atmosphere are coming into our view as the brown dwarf spins on its axis,” said Radigan.

The team quickly took into account all possibilities for the differences in magnitude – from the possibility of a binary companion to cool magnetic spots – but none of these answers were likely. What could be causing this difference in brightness that seemed to be rotational?

“We might be looking at a gigantic storm raging on this brown dwarf, perhaps a grander version of the Great Red Spot on Jupiter in our own solar system, or we may be seeing the hotter, deeper layers of its atmosphere through big holes in the cloud deck,” said co-author Professor Ray Jayawardhana, Canada Research Chair in Observational Astrophysics at the University of Toronto and author of the recent book Strange New Worlds: The Search for Alien Planets and Life beyond Our Solar System.

Using computer modeling, astronomers can hypothesize what may be going on as silicates and metals mix over a variety of temperatures. The result is a condensate cloud. Thanks to 2MASS J2139’s variability, we’re able to observe what may be evolving “weather patterns”. These models may one day help us to extrapolate extra-solar giant planet weather conditions.

“Measuring how quickly cloud features change in brown dwarf atmospheres may allow us to infer atmospheric wind speeds eventually and teach us about how winds are generated in brown dwarf and planetary atmospheres,” Radigan added.

Original Story Source: University of Toronto News. For Further Reading: High Amplitude, Periodic Variability of a Cool Brown Dwarf: Evidence for Patchy, High-Contrast Cloud Features.

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21 Responses

  1. How far away is it? We need some ultra fast mini probes that can be launched on a whim to take pictures of relatively close objects. Each orbital launch could take up several dozen and spray them across our galaxy! Only takes one month at 1 g acceleration to reach a considerable portion of light speed! We could have intimate knowledge of our neighborhood in 30 years!

  2. Fred Trafton says

    Using what for fuel? You’ll still be long dead before we get pictures back. Oh, and how will we be able to receive a signal to get those pictures? How many megawatts of a transmitter would be needed for us to be able to detect a signal with a sun right behind it? I don’t think so. Space-based observations from within our own solar system are far more promising.

  3. Fred Trafton says

    Using what for fuel? You’ll still be long dead before we get pictures back. Oh, and how will we be able to receive a signal to get those pictures? How many megawatts of a transmitter would be needed for us to be able to detect a signal with a sun right behind it? I don’t think so. Space-based observations from within our own solar system are far more promising.

  4. Fred Trafton says

    Using what for fuel? You’ll still be long dead before we get pictures back. Oh, and how will we be able to receive a signal to get those pictures? How many megawatts of a transmitter would be needed for us to be able to detect a signal with a sun right behind it? I don’t think so. Space-based observations from within our own solar system are far more promising.

    • Anonymous says

      Photons collimated by a Fresnel lens can send a light reflecting sail to about .5c (half light speed), which is not bad. We could send probes out to 20 light years, enough to take a look at the Gliese 581 planets. More below

      LC

      • squidgeny says

        Yes, enough to take “a look”. I would imagine that if the probe is travelling at half the speed of light, one look is about as much as we could hope for. Getting the probe there is only half the challenge – how would we slow it down for a decent period of meaningful observations?

      • Anonymous says

        The retrograde motion of a photon sail can be performed. Picture the photon sail as a large disk, about 10km in radius. This is made of ultra-thin material, so as to keep the mass low, with a small craft at the radial center and various controlling struts and lines. An inner portion of the disk detaches and the outer part is a reflecting annulus which directs reflected photons back to the inner disk. This serves to reduce the velocity of the inner disk.

        This is somewhat complicated of course as a physics problem. As your spacecraft reaches a significant percentage of the speed of light the photons which push it forwards are red shifted in the frame of the craft. This reduces the acceleration of the craft. Then with two mirrors things get a bit more complicated.

        Once the inner craft reaches the target stellar system it uses the photon sail as a propulsion system using the photons produced by the star. The craft may navigate around the stellar system for several years and maybe drop landing craft on planets of interest.

        LC

      • squidgeny says

        Presumably a solar sail good enough to decelerate on the light of the destination star is also good enough to accelerate on the light on the origin star (redshift aside)… in which case, the Fresnel lens would be unnecessary wouldn’t it?

        Unless you were going to use it to give the spacecraft additional kinetic enrgy on top of the solar sail’s efforts. But if that were so, wouldn’t that then mean the spacecraft has more kinetic energy than it would be able to shed using its solar sail alone at the destination star?

      • Anonymous says

        EM radiation from the sun drops off as 1/r^2. The point of the Fresnel lens is to collimate photons into a narrow beam. Fresnel lenses are used in light houses to direct a beam, and form the base of those overhead projectors that are now becoming old fashioned. That way when the photon sail accelerates far out beyond Pluto and even more reaches the target star there is a reasonable photon flux. The Fresnel lens is positioned in space in solar orbit to direct solar photons at the photon sail. Of course some complicated beam steering and directing of light towards the lens is required.

        LC

      • squidgeny says

        I get that, but if we didn’t have a Fresnel lens at the destination star, how would enough light be supplied to slow the space probe back down?

      • Anonymous says

        The disk shaped photon sail releases a smaller disk in the middle where the core of the ship is. The remaining annulus reflects light back to the smaller “core.” The annular part accelerates off into space, but the core craft is decelerated.

        LC

      • squidgeny says

        I think I need a diagram. lol!

      • Anonymous says

        The engineering theory is based on Robert Forwards’ idea of the StarWisp. There he suggests using microwaves send by a large maser. I discussed a similar thing using a Fresnel lens, which seems simpler to me. The propulsion and breaking scheme is illustrated in his paper

        http://www.transorbital.net/Library/D001_AxA.html

        LC

      • Anonymous says

        Your work on the Fresnel sail craft would have been my choice for a submission to the 100 Year Spaceship contest. It avoid getting bogged down on what is likely unresolvable physics limitations (thus sub-luminal).

        It was my understanding that the Fresnel sail is something that could realistically be developed this century by an entrepreneurial space agency.

        Either way, we should start seriously considering how we can send probes to these worlds that will undoubtedly crop up close to home.

      • Anonymous says

        I suppose I could have done that. I was not sure how well it would fit in though. I had an idea with a directed inflaton field, but I found a problem with this idea.

        LC

  5. HawksHockey says

    My extreme compliments to LC and thoses talking to him on the wonderful knowledge they possess. I find the subject matter facinating, but unfortunately, am limited on what I understand and am able to absorb. Re-watched Apollo 13 last night and am still amazed at the brilliance that not only sent those men into space – but more so, the absolute genius (and team work) that brought them home. Thank you, all of you.

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