The Subaru Telescope, located on the summit of Mauna
Kea, is dedicated to exploring the cosmos, gaining a deeper and more
thorough understanding of everything that surrounds us. With an 8.2-meter
mirror and a suite of sophisticated instruments, astronomers at Subaru
Telescope explore nearby stars looking for planetary systems. A giant step
towards this goal was made recently with the “first-light” inauguration of a
new state-of-the-art instrument.
There are eight innovative cameras and spectrographs at Subaru optimized
for various astronomical investigations in optical and near-infrared
wavelengths. On the night of December 3, 2007, a new instrument was
brought to life, HiCIAO (High Contrast Instrument for the Subaru Next
Generation Adaptive Optics). The HiCIAO camera is designed as a
technologically adaptable system that will replace the infrared CIAO
(Coronagraphic Imager with Adaptive Optics) unit that has been in operation
since April 2000. Both systems are designed to block out the harsh direct
light from a star, so that nearby faint objects such as planets can be viewed.
The new system benefits from a contrast improvement of 10 to 100 times
better than before, allowing astronomers glimpses into regions never
explored. A further advantage of the HiCIAO camera is that it will be used
in concert with an adaptive optics (AO) system that was recently
significantly upgraded, which, in turn, increased the clarity of Subaru’s
vision by a factor of ten, opening up more of the night sky to observing. The
new AO system uses 188 actuators behind a deformable mirror to remove
the atmospheric distortion from its view, allowing Subaru Telescope to
observe close to its theoretical performance limits. In conjunction with the
new AO system a laser guide star system was installed so that any part of the
sky can now be observed.
The HiCIAO system, initiated in 2004, was developed by an ambitious team
of scientists and engineers from the Subaru Telescope, National
Astronomical Observatory of Japan, and the University of Hawaii’s Institute
for Astronomy. Dr. Ryuji Suzuki, a Subaru astronomer leading the HiCIAO instrument development, says “the unique instrument was primarily designed for the direct
detection of extrasolar planets and disks”. The system’s innovative design
allows for high contrast coronagraphic techniques in three observing modes:
direct imaging, polarization differential imaging, and spectral differential
imaging. HiCIAO directly detects and characterizes young extrasolar
planets and brown dwarfs, sub-stellar objects that occupy the mass range
between that of large gas giant planets (e.g. Jupiter) and the lowest mass
stars. With the aid of the laser guide star AO system, HiCIAO targets dim
objects including young stars, protostars, and star forming regions. HiCIAO
is also extremely useful detecting faint dust disks around nearby stars
studying small-scale and inner disk structures and dust grain properties,
leading to a clearer understanding of extra-solar planetary systems and their
evolutionary processes. In addition, the instrument will be used as a test bed for various
future upgrades to allow higher contrast coronagraph and
an imaging spectrometer that would lead to deeper searches of the
smaller planets. Dr. Suzuki reports that “although we already know more than 250 extrasolar planets, they have all
proven their existence by indirect evidences like the Doppler or transit
method. Because the direct imaging of an extrasolar planet has never convincingly been done, if it happens, that will be exciting”. Subaru Telescope hopes to be the
first to directly observe a planet outside our solar system.
December 26 , 2007
Guidelines
for Use of Subaru Images |
