This illustration shows HD 189733b, a huge gas giant that orbits very close to its host star HD 189733.
(USA TODAY) -- Data from the Hubble space telescope has helped determine that a
planet orbiting a nearby star likely shares Earth's deep-blue tones, but
the similarities stop there, astronomers report.
planet, HD 189733b, circles a star some 63 light years away, about 372
trillion miles, according to the upcoming Astrophysical Journal Letters
report led by the University of Oxford's Tom Evans. The Jupiter-sized
planet, about 13% heftier than the largest planet in our solar system,
orbits very close to its star, circling it once every 2.2 days. That
makes it a (very) "Hot Jupiter" planet, the study notes, with cloud
temperatures likely around 1,800 degrees Fahrenheit and winds whipping
around at 4,350 miles-per-hour.
Astronomers have detected
more than 800 "exoplanets" -- planets that orbit stars outside our solar
system -- in the last two decades. HD 189733b was discovered in 2005.
planet's clouds are likely blue, based on spectroscope data from
Hubble, according to the international team of astronomers. The space
telescope peered at the planet, before, during and after it was eclipsed
by its star. That enabled the astronomers to subtract the light from
the star from the light reflected off the planet, giving them a sense of
"We saw the brightness of the whole system drop
in the blue part of the spectrum when the planet passed behind its
star," Evans says, in a statement. "From this, we can gather that the
planet is blue, because the signal remained constant."
team suggests the blue color likely comes from a hazy atmosphere filled
with melting glass particles, ones that scatter blue light.
is by no means a giant step forward, but a nice observation with
implications for clouds in this hot Jupiter's atmosphere, one of the key
details for those who model the atmospheres of these hot planets," says
planetary theorist Alan Boss of the Carnegie Institution of Washington,
D.C. "It is amazing to think that we can now make measurements that
tell us something about the cloud cover on distant exoplanets, and is
especially amazing when we cannot even see these hot Jupiters directly."