New camera on Subaru Telescope may directly observe exoplanets

January 3, 2008, Hilo, HI--The new HiCIAO camera on the Subaru Telescope on Mauna Kea has seen first light.

Jan 3rd, 2008

January 3, 2008, Hilo, HI--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 the 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 camera.

Subaru uses eight innovative cameras and spectrographs optimized for various astronomical investigations in optical and near-infrared wavelengths. On the night of December 3, 2007, the High Contrast Instrument for Adaptive Optics (HiCIAO) camera was brought to life. The HiCIAO is a technologically adaptable system that will replace the infrared Coronagraphic Imager with Adaptive Optics (CIAO) unit 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 ten to 100 times, 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 atmospheric distortion, allowing the Subaru Telescope to observe close to its theoretical performance limits. In addition, a laser guide-star system was installed to enable observations of tiny regions of sky without bright stars to steady the AO system on.

The HiCIAO system, initiated in 2004, was developed by a 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 project, says "the unique instrument was primarily designed for the direct detection of extrasolar planets and disks." The system's 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 for detecting faint dust disks around nearby stars, and for studying small-scale and inner disk structures and dust grain properties, both of which lead to a clearer understanding of extra-solar planetary systems and their evolutionary processes. Dr. Suzuki reports that "although we already know of more than 250 extrasolar planets, they have all proven their existence indirectly by the Doppler or transit method. Because the direct imaging of an extrasolar planet has never been done, if it happens, that will be exciting." Subaru Telescope may be the first to directly observe a planet outside our solar system.

For more information about HiCIAO and other innovative technologies operating at Subaru Telescope, visit www.subarutelescope.org. ---VC

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