sunset from behind the wire

sunset from behind the wire

Sunday, December 13, 2015

Clouds and Storms on Stars


This illustration shows a cool star, called W1906+40, marked by a raging storm near one of its poles. The storm is thought to be similar to the Great Red Spot on Jupiter. Scientists discovered it using NASA's Kepler and Spitzer space telescopes.

Astronomers have discovered what appears to be a tiny star with a giant, cloudy storm, using data from NASA's Spitzer and Kepler space telescopes. The dark storm is akin to Jupiter's Great Red Spot: a persistent, raging storm larger than Earth.
"The star is the size of Jupiter, and its storm is the size of Jupiter's Great Red Spot," said John Gizis of the University of Delaware, Newark. "We know this newfound storm has lasted at least two years, and probably longer." Gizis is the lead author of a new study appearing in The Astrophysical Journal.
While planets have been known to have cloudy storms, this is the best evidence yet for a star that has one. The star, referred to as W1906+40, belongs to a thermally cool class of objects called L-dwarfs. Some L-dwarfs are considered stars because they fuse atoms and generate light, as our sun does, while others, called brown dwarfs, are known as "failed stars" for their lack of atomic fusion.

The L-dwarf in the study, W1906+40, is thought to be a star based on estimates of its age (the older the L-dwarf, the more likely it is a star). Its temperature is about 3,500 degrees Fahrenheit (2,200 Kelvin). That may sound scorching hot, but as far as stars go, it is relatively cool. Cool enough, in fact, for clouds to form in its atmosphere.

Spitzer has observed other cloudy brown dwarfs before, finding evidence for short-lived storms lasting hours and perhaps days.
John E. Gizis, Kyle G. Dettman, Adam J. Burgasser, Sara Camnasio, Munazza Alam, Joseph C. Filippazzo, Kelle L. Cruz, Stanimir Metchev, Edo Berger, Peter K. G. Williams. Kepler Monitoring of an L Dwarf. II. Clouds with Multi-year Lifetimes. The Astrophysical Journal, 2015; 813 (2): 104 DOI: 10.1088/0004-637X/813/2/104
In the new study, cited above, the astronomers were able to study changes in the atmosphere of W1906+40 for two years. The L-dwarf had initially been discovered by NASA's Wide-field Infrared Survey Explorer in 2011. Later, Gizis and his team realized that this object happened to be located in the same area of the sky where NASA's Kepler mission had been staring at stars for years to hunt for planets.

Kepler identifies planets by looking for dips in starlight as planets pass in front of their stars. In this case, astronomers knew observed dips in starlight weren't coming from planets, but they thought they might be looking at a star spot -- which, like our sun's "sunspots," are a result of concentrated magnetic fields. Star spots would also cause dips in starlight as they rotate around the star.

Follow-up observations with Spitzer, which detects infrared light, revealed that the dark patch was not a magnetic star spot but a colossal, cloudy storm with a diameter that could hold three Earths. The storm rotates around the star about every 9 hours. Spitzer's infrared measurements at two infrared wavelengths probed different layers of the atmosphere and, together with the Kepler visible-light data, helped reveal the presence of the storm.

While this storm looks different when viewed at various wavelengths, astronomers say that if we could somehow travel there in a starship, it would look like a dark mark near the polar top of the star.


13 comments:

  1. I am starting to become concerned about you, LL: not a single harsh word about Hillary Clinton or Barack Obama in this post, but rather simply droning on and on about astronomical blither blather.

    Brain lesion, perhaps? Or a late night on the town, more likely. I am hoping that I see the next post full of venom and loathing of all things liberal, you know, the old LL that we all know and love.

    Get well, OK LL?

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    1. Sorry for the lack of invective...I'm clearly not myself.

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    2. I'm sure you'll shake it off, and then your old self will be back, good as new: flecks of spittle flying from your open maw as you excoriate those who would wish our country harm (aka liberals).

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    3. Did you see the post from earlier in the morning regarding Bill Clinton?

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  2. No, but upon your prompt I scrolled down and read it. Yes, Bubba will be a handful if allowed back in the Oval Office. And I have other names for Barry, but you've heard them all. I never knew Hillary was a bull dike, but I am not shocked (SHOCKED!).

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    1. Yoko Ono outed her officially (and reported wildly on-line), but it's one of those things people have known for decades. I think that it ticked her off that Bill always ended up with the hot women and she had to take the cast-offs and sweat hogs. Bill had his pick and could cut one out of the herd. Hillary had to 'go ugly early' in the evening in the hopes of catching a stray. They are a couple made for politics.

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  3. Larry, you are so prolific I can't keep up with you. I need a day off just to follow you. So, I'll leave the political ranting to those that are better informed than I and stick to pretty planets. Space has a way of making everything else seem so insignificant.
    It is very pretty star, don't you think?
    A colossal cloudy storm? Sounds like England.


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    1. Space is beautiful, the sky is beautiful - there is no such thing as an imperfect sky. It helps to keep us all humble.

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  4. Thanks for the star update. But a massive cloudy storm? I didn't know the Episcopal Church had gotten so big.

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  5. THey are doing some amazing research these days... :-)

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It's virtual - it's a mirage - it's life