Figure 1: Gemini Planet Imager’s first light image of Beta Pictoris b, a
planet orbiting the star Beta Pictoris. The star, Beta Pictoris, is
blocked in this image by a mask so its light doesn’t interfere with the
light of the planet. In addition to the image, GPI obtains a spectrum
from every pixel element in the field of view to allow scientists to
study the planet in great detail.
Beta Pictoris b is a giant planet – several times larger than Jupiter –
and is approximately ten million years old. These near-infrared images
(1.5-1.8 microns) show the planet glowing in infrared light from the
heat released in its formation. The bright star Beta Pictoris is hidden
behind a mask in the center of the image. Image credit: Processing by Christian Marois, NRC Canada. High Resolution TIF | Full Resolution JPG
Figure 2: Gemini Planet Imager’s first light image of the light
scattered by a disk of dust orbiting the young star HR4796A. This narrow
ring is thought to be dust from asteroids or comets left behind by
planet formation; some scientists have theorized that the sharp edge of
the ring is defined by an unseen planet. The left image (1.9-2.1
microns) shows normal light, including both the dust ring and the
residual light from the central star scattered by turbulence in the
Earth’s atmosphere. The right image shows only polarized light.
Leftover
starlight is unpolarized and hence removed from this image. The light
from the back edge of the disk is strongly polarized as it scatters
towards us. Image credit: Processing by Marshall Perrin, Space Telescope Science Institute. Full Resolution JPG
Figure 3: Comparison of Europa observed with Gemini Planet Imager in K1
band on the right and visible albedo visualization based on a composite
map made from Galileo SSI and Voyager 1 and 2 data (from USGS) on the
left. While GPI is not designed for ‘extended’ objects like this, its
observations could help in following surface alterations on icy
satellites of Jupiter or atmospheric phenomena (e.g. clouds, haze) on
Saturn’s moon Titan. The GPI near-infrared color image is a combination
of 3 wavelength channels. Image credit: Processing by Marshall Perrin, Space Telescope. Science Institute and Franck Marchis SETI Institute. High Resolution TIF | Full Resolution JPG
World's most powerful exoplanet camera turns its eye to the sky
GPI facility and team photos can be found here.
After nearly a decade of development, construction, and testing, the
world’s most advanced instrument for directly imaging and analyzing
planets around other stars is pointing skyward and collecting light from
distant worlds.
The instrument, called the Gemini Planet Imager (GPI), was designed,
built, and optimized for imaging faint planets next to bright stars and
probing their atmospheres. It will also be a powerful tool for studying
dusty, planet-forming disks around young stars. It is the most advanced
such instrument to be deployed on one of the world’s biggest
telescopes – the 8-meter Gemini South telescope in Chile.
“Even these early first-light images are almost a factor of 10 better
than the previous generation of instruments. In one minute, we are
seeing planets that used to take us an hour to detect,” says Bruce
Macintosh of the Lawrence Livermore National Laboratory who led the team
that built the instrument.
GPI detects infrared (heat) radiation from young Jupiter-like planets in
wide orbits around other stars, those equivalent to the giant planets
in our own Solar System not long after their formation. Every planet GPI
sees can be studied in detail.
“Most planets that we know about to date are only known because of
indirect methods that tell us a planet is there, a bit about its orbit
and mass, but not much else,” says Macintosh. “With GPI we directly
image planets around stars – it’s a bit like being able to dissect the
system and really dive into the planet’s atmospheric makeup and
characteristics.”
GPI carried out its first observations last November – during an
extremely trouble-free debut for an extraordinarily complex astronomical
instrument the size of a small car. “This was one of the smoothest
first-light runs Gemini has ever seen” says Stephen Goodsell, who
manages the project for the observatory.
For GPI’s first observations, the team targeted previously known
planetary systems, including the well-known Beta Pictoris system; in it
GPI obtained the first-ever spectrum of the very young planet Beta
Pictoris b. The first-light team also used the instrument’s polarization
mode – which can detect starlight scattered by tiny particles – to
study a faint ring of dust orbiting the very young star HR4796A. With
previous instruments, only the edges of this dust ring, (which may be
the debris remaining from planet formation), could be seen, but with GPI
astronomers can follow the entire circumference of the ring.
Although GPI was designed to look at distant planets, it can also
observe objects in our Solar System. The accompanying test images of
Jupiter’s moon Europa, for example, can allow scientists to map changes
in the satellite’s surface composition. The images were released today (January 7, 2014)
at the 223rd meeting of the American Astronomical Society in Washington
DC.
“Seeing a planet close to a star after just one minute, was a thrill,
and we saw this on only the first week after the instrument was put on
the telescope!” says Fredrik Rantakyro a Gemini staff scientist working
on the instrument. “Imagine what it will be able to do once we tweak and
completely tune its performance.”
“Exoplanets are extraordinarily faint and difficult to see next to a
bright star,” notes GPI chief scientist Professor James R. Graham of the
University of California who has worked with Macintosh on the project
since its inception. GPI can see planets a million times fainter than
their parent stars. Often described, ‘like trying to see a firefly
circling a streetlight thousands of kilometers away,’ instruments used
to image exoplanets must be designed and built to “excruciating
tolerances,” points out Leslie Saddlemyer of NRC Herzberg (part of the
National Research Council of Canada), who served as GPI’s systems
engineer. “Each individual mirror inside GPI has to be smooth to within a
few times the size of an atom,” Saddlemyer adds.
“GPI represents an amazing technical achievement for the international
team of scientists who conceived, designed, and constructed the
instrument, as well as a hallmark of the capabilities of the Gemini
telescopes. It is a highly-anticipated and well-deserved step into the
limelight for the Observatory”, says Dr. Gary Schmidt, program officer
at the National Science Foundation (NSF), which funded the project along
with the other countries of the Gemini Observatory partnership.
“After years of development and simulations and testing, it’s incredibly
exciting now to be seeing real images and spectra of exoplanets
observed with GPI. It’s just gorgeous data,” says Marshall Perrin of the
Space Telescope Science Institute.
“The entire exoplanet community is excited for GPI to usher in a whole
new era of planet finding,” says physicist and exoplanet expert Sara
Seager of the Massachusetts Institute of Technology. Seager, who is not
affiliated with the project adds, “Each exoplanet detection technique
has its heyday. First it was the radial velocity technique (ground-based
planet searches that started the whole field). Second it was the
transit technique (namely Kepler). Now,” she says, “it is the ‘direct
imaging’ planet-finding technique’s turn to make waves.”
In 2014, the GPI team will begin a large-scale survey, looking at 600
young stars to see what giant planets orbit them. GPI will also be
available to the whole Gemini community for other projects, ranging from
studies of planet-forming disks to outflows of dust from massive, dying
stars.
Looking through Earth’s turbulent atmosphere, even with advanced
adaptive optics, GPI will only be able to see Jupiter-sized planets. But
similar technology is being proposed for future space telescopes.
“Some day, there will be an instrument that will look a lot like GPI, on
a telescope in space,” Macintosh projects. “And the images and spectra
that will come out of that instrument will show a little blue dot that
is another Earth.”
GPI is an international project led by the Lawrence Livermore National
Laboratory (LLNL) under Gemini’s supervision, with Macintosh as
Principal Investigator and LLNL engineer David Palmer as project
manager. LLNL also produced the advanced adaptive optics system that
measures and corrects for atmospheric turbulence a thousand times per
second. Early research and development that led to the GPI project were
supported by the National Science Foundation's Center for Adaptive
Optics. Key technologies such as the deformable mirror were tested at
the UC Observatories' Laboratory for Adaptive Optics, led by Donald
Gavel. Scientists at the American Museum of Natural History, led by Ben
Oppenheimer (who also led a project demonstrating some of the same
technologies used in GPI on the 5-meter Palomar project) designed
special masks that are part of the instrument’s coronagraph which blocks
the bright starlight that can obscure faint planets. Engineer Kent
Wallace and a team from NASA’s Jet Propulsion Laboratory constructed an
ultra-precise infrared wavefront sensor to measure small distortions in
starlight that might mask a planet. A team at the University of
California Los Angeles’ Infrared Laboratory, under the supervision of
Professor James Larkin, together with Rene Doyon at the University of
Montreal, assembled the infrared spectrograph that dissects the light
from planets. Data analysis software written at University of Montreal
and the Space Telescope Science Institute assembles the raw spectrograph
data into three-dimensional cubes. NRC Herzberg in British Columbia
Canada, built the mechanical structure and software that knits all the
pieces together. James R. Graham, as project scientist, led the
definition of the instrument’s capabilities. The instrument underwent
extensive testing in a laboratory at the University of California Santa
Cruz before shipping to Chile in August. Franck Marchis at the SETI
institute in California manages GPI’s data and communications.
Media Contacts:
-
Peter Michaud
Gemini Observatory, Hilo, HI
Email: pmichaud@gemini.edu
Cell: (808) 936-6643
Desk: (808) 974-2510
Science Contacts:
- Bruce Macintosh
Lawrence Livermore National Laboratory
Email: macintosh1@llnl.gov
Desk: (925) 423-8129
- James R. Graham
University of California Berkeley
Email: jrg@berkeley.edu
Cell: (510) 926-9820
- Marshall Perrin
Space Telescope Science Institute
Email: mperrin@stsci.edu
Cell: (410) 507-5483
Desk: (410) 338-4789
