NASA Telescopes Detect Jupiter-like Storm on Small Star
Date :
December 12, 2015
Source :
NASA/Jet Propulsion
Laboratory
Summary : 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.
Keterangan
gambar : 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.
Credit:
NASA/JPL-Caltech
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. "The
L-dwarf's clouds are made of tiny minerals," said Gizis. Spitzer has observed other cloudy brown dwarfs before, finding evidence
for short-lived storms lasting hours and perhaps days.
In the new study, 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.
The researchers plan to look for other stormy stars and brown dwarfs
using Spitzer and Kepler in the future. "We don't
know if this kind of star storm is unique or common, and we don't why it
persists for so long," said Gizis. Other authors
of the study are: Adam Burgasser--University of California, San Diego; Kelle
Cruz, Sara Camnasio and Munazza Alam--Hunter College, New York City, New York;
Stanimir Metchev--University of Western Ontario, Canada; Edo Berger and Peter
Williams--Harvard-Smithsonian Center for Astrophysics, Cambridge,
Massachusetts; Kyle Dettman--University of Delaware, Newark; and Joseph
Filippazzo--College of Staten Island, New York. NASA's Ames
Research Center in Moffett Field, California, manages the Kepler and K2
missions for NASA's Science Mission Directorate. JPL managed Kepler mission
development. Ball Aerospace & Technologies Corp. operates the flight system
with support from the Laboratory for Atmospheric and Space Physics at the
University of Colorado in Boulder.
JPL manages the Spitzer Space Telescope mission for NASA. Science
operations are conducted at the Spitzer Science Center at the California
Institute of Technology in Pasadena. Spacecraft operations are based at
Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived
at the Infrared Science Archive housed at the Infrared Processing and Analysis
Center at Caltech.
Caltech
manages JPL for NASA.
Story Source:
The above post
is reprinted from materials provided by NASA/Jet
Propulsion Laboratory. Note:
Materials may be edited for content and length.
Journal
Reference:
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
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