Small, Ground-Based Telescope Images Three Exoplanets

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA 91109. TELEPHONE 818-354-5011
http://www.jpl.nasa.gov

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

News release: 2010-128 April 14, 2010

Small, Ground-Based Telescope Images Three Exoplanets

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-128&cid=release_2010-128

PASADENA, Calif. -- Astronomers have snapped a picture of three planets orbiting a
star beyond our own using a modest-sized telescope on the ground. The surprising feat
was accomplished by a team at NASA's Jet Propulsion Laboratory in Pasadena, Calif.,
using a small portion of the Palomar Observatory's Hale Telescope, north of San Diego.

The planets had been imaged previously by two of the world's biggest ground-based
telescopes -- one of the two 10-meter (33-foot) telescopes of W.M. Keck Observatory
and the 8.0-meter (26-foot) Gemini North Observatory, both on Mauna Kea in Hawaii.
The planets, which orbit the star HR 8799, were among the very first to be directly
imaged, a discovery announced in Nov. of 2008.

The new image of the planets, taken in infrared light as before, was captured using just a
1.5-meter-diameter (4.9-foot) portion of the Hale telescope's mirror. The astronomy team
took painstaking efforts to push current technology to the point where such a small mirror
could be used. They combined two techniques -- adaptive optics and a coronagraph -- to
minimize the glare from the star and reveal the dim glow of the much fainter planets.

The picture is online at http://www.nasa.gov/topics/universe/features/exoplanet20100414-a.html.

"Our technique could be used on larger ground-based telescopes to image planets that are
much closer to their stars, or it could be used on small space telescopes to find possible
Earth-like worlds near bright stars," said Gene Serabyn, an astrophysicist at JPL and
visiting associate in physics at the California Institute of Technology in Pasadena.
Serabyn is lead author of a report on the findings in the April 15 issue of the journal
Nature.

The three planets, called HR8799b, c and d, are thought to be gas giants similar to Jupiter,
but more massive. They orbit their host star at roughly 24, 38 and 68 times the distance
between our Earth and sun, respectively (our Jupiter resides at about five times the Earth-
sun distance). It's possible that rocky worlds like Earth circle closer to the planets' star,
but with current technology, they would be impossible to see under the star's glare.

The star HR 8799 is a bit more massive than our sun, and much younger, at about 60
million years, compared to our sun's approximately 4.6 billion years. It is 120 light-years
away in the constellation Pegasus. This star's planetary system is still active, with bodies
crashing together and kicking up dust, as recently detected by NASA's Spitzer Space
Telescope (http://spitzer.caltech.edu/news/1000-feature09-16-Unsettled-Youth-Spitzer-Observes-a-Chaotic-Planetary-System). Like fresh-baked bread out of the oven, the
planets are still warm from their formation and emit enough infrared radiation for
telescopes to see.

To take a picture of HR 8799's planets, Serabyn and his colleagues first used a method
called adaptive optics to reduce the amount of atmospheric blurring, or to take away the
"twinkle" of the star. This technique was optimized by using only a small piece of the
telescope. Once the twinkle was removed, the light from the star itself was blocked using
the team's coronograph, an instrument that selectively masks out the star. A novel "vortex
coronagraph," invented by team member Dimitri Mawet of JPL, was used for this step.
The final result was an image showing the light of three planets.

"The trick is to suppress the starlight without suppressing the planet light," said Serabyn.

The technique can be used to image the space lying just fractions of a degree from a star
(about one degree divided by roughly 10,000). This is as close to the star as that achieved
by Gemini and Keck -- telescopes that are about five and seven times larger, respectively.

Keeping telescopes small is critical for space missions. "This is the kind of technology that
could let us image other Earths," said Wesley Traub, the chief scientist for NASA's
Exoplanet Exploration Program at JPL. "We are on our way toward getting a picture of
another pale blue dot in space."

JPL is a partner with the California Institute of Technology in Pasadena in the Palomar
Observatory. Caltech manages JPL for NASA. More information about exoplanets and
NASA's planet-finding program is at http://planetquest.jpl.nasa.gov . More information
about the Palomar Observatory is at http://www.astro.caltech.edu/palomar/ .

-end-

To remove yourself from this mailing, please go to http://www.kintera.org/TR.asp?a=iuLPI8PQIeJUJjL&s=eoKQLPNpGaICLOPvFoE&m=rkI0IaMQJfL2F

To remove yourself from all mailings from NASA Jet Propulsion Laboratory, please go to http://www.kintera.org/TR.asp?a=ceIDJQMsG8IJL2J&s=eoKQLPNpGaICLOPvFoE&m=rkI0IaMQJfL2F