A team of Japanese astronomers from the National Astronomical Observatory of Japan, Tokyo University, and Kyoto University in Japan obtained infrared and high-resolution images of galaxies from 11 billion years ago using the adaptive optics (AO) system and the infrared camera and spectrograph (IRCS) on the Subaru Telescope. Thanks to the removal of atmospheric blur by the AO system, high spatial resolution imaging was achieved in the near-infrared and the profiles of the distant galaxies were revealed. The images of the distant galaxies show almost all of the galaxies have a light profile similar to the disk galaxies in the local universe.

In July 2005, NASA’s Deep Impact Mission was watched closely by a worldwide audience as a large metal impactor crashed into Comet Tempel 1 to study the internal material and nucleus of the comet (see Sept. 15 2005 report). Since then, the spacecraft, which launched the impactor, has been wandering the solar system looking for its next object of interest. Astronomers from the University of Hawaii, Subaru Telescope, and other large telescopes have searched for Comet Boethin as the next target, but due to its faintness its exact location was hard to pinpoint. After an exhaustive search, NASA has decide to go after another comet, Hartley 2, and they call the mission EPOXI.

A team of 15 astronomers observed the dwarf spheroidal galaxy Leo II and found that the galaxy is more extended than previously thought and established a star-formation history of this galaxy.

A new image of a young (less than a million years old) binary star system called XZ Tauri, taken using the Coronagraphic Imager with Adaptive Optics (CIAO) on the Subaru Telescope, reveals for the first time a jet of material streaming away from the pair's primary star. An earlier observation made by Hubble Space Telescope showed a jet streaming from the secondary. This new jet is misaligned with the secondary jet by about 30 degrees. The discoveries of jets coming from both of these young stars suggests that they could each have a circumstellar disk with sites of planetary formation hidden inside. The jets are formed as gas from the disks is channeled through magnetic fields surrounding the binary system and forced out to space at high speed. Their misalignment may indicate some intricate interaction between the two stars and their disks.

(Japanese only)

When meteoroids flash through the Earth’s atmosphere, they bore tunnels through the air, leaving behind narrow meteor tracks that are heated by the collision of the fast-moving incoming object with atoms of highly diluted atmospheric gases. Most meteoroids are bits of space debris the size of a grain of sand. The width of the tracks they make has long been known to be narrower than a meter, but until recently, more precise measurements have been impossible to make.

A Japanese/US collaboration led by a researcher from the University of Tokyo observed the transiting extrasolar planetary system TrES-1 and measured the angle between the stellar spin axis and the planetary orbital axis using the Subaru Telescope High Dispersion Spectrograph (HDS). By measuring the degree of alignment in transiting systems, one can constraint planetary formation models proposed to explain the diverse properties of extrasolar planets. It was the third case and the faintest target so far for which the spin-orbit alignment has been measured.

Astronomers from the National Astronomical Observatory of Japan and Osaka Kyoiku University in Japan, have detected the element thorium in a red giant star called COS82, which lies in the Ursa Minor dwarf galaxy. Their discovery marks the first abundance determination of the actinides element thorium in a star beyond the Milky Way, and follows the detection of thorium in more than ten stars within the Milky Way. The derived thorium abundance indicates that the explosive synthesis of heavy elements occurs in similar-type environments in both the Milky Way and the Ursa Minor dwarf galaxy, which is a satellite of the Milky Way.

Cometary nuclei are believed to contain important information on the condition of the solar nebula, but there is little observational data available on their interior structure. Our ground-based observations of NASA’s Deep Impact event show that comet 9P/Tempel 1 has a surface layer consisting of small (sub-micron sized) carbonaceous grains whose thickness is several tens of cm. This suggests that comet 9P/Tempel 1 contains at several tens of cm of depth material that has not metamorphosed since this comet left the trans-Neptunian region. This further implies that many short-period comets may maintain the components they had upon leaving the trans-Neptunian region at ~ 1 m of depth from the surface even after numerous perihelion passages.

(Japanese Only)

Precise analysis of a high-resolution image of Comet　73P/Schwassman-Wachmann　3 (SW3)　taken in May 2006 by the Subaru Telescope, reveals that one chunk called Fragment B is split into at least 50 fragments. This is well more than the 13 estimated when the image was first released in 2006.

A new image of the Crab Nebula supernova remnant taken using the Prime Focus Camera (Suprime-Cam) on the Subaru telescope highlights the beauty of stellar debris expanding away from the site of this ancient blast. The high-resolution image captures details of an elongated tendril of gas rushing out at roughly 1,500 kilometers per second. While the nebula has been observed many times using both ground- and space-based telescopes, this image is giving astronomers another opportunity to study the mechanics of the expanding gas in much greater detail.

Researchers from the National Astronomical Observatory of Japan (NAOJ) and the University of Tokyo used Subaru's Suprime-Cam camera to discover an unusual streak of ionized hydrogen gas associated with a galaxy 300 million light-years from Earth. The filament of gas is only 6 thousand light-years wide, yet extends 200,000 light-years, about the distance between the Milky Way Galaxy and its companion, the Large Magellanic Cloud. Finding such an extremely narrow and long ionized gas cloud is a first in astronomy.

An international research team from the University of Jena (Germany), Nagoya University, and the Harvard-Smithsonian Center (USA) recently obtained the first images of the second "sun" around a planet-hosting star, gamma Cephei, using the Subaru telescope and the 3.5-meter telescope at Calar Alto (Spain). This direct detection significantly improves our knowledge of the system, such as the masses of the two stars and the minimum mass of the planet.

An international team of astronomers led by Nick Scoville from the California Institute of Technology have created a three dimensional map that provides the first direct look at the large-scale distribution of matter in the universe. This is best evidence yet that normal matter, like stars and galaxies, accumulate along the densest concentrations of invisible dark matter. The map extends to a time when the universe was only half its current size and shows that dark matter has grown increasingly clumpy, forming long flamentary structures. Observations with the Subaru telescope, led by Yoshiaki Taniguchi from Ehime University, contributed the 3D distance and time information. Details are in a paper by Richard Massey et al. in the journal Nature (January 7, 2007 edition).