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Thursday, May 10, 2012

New Molecule of Interstellar And Star Formation Has Been Detected

Ophiuchi star formation region detected by GREAT

Optical color image of the rho Ophiuchi star formation region, about 400 light-years from Earth, with dark dusty filamentary gas clouds. The position of the optically obscured low-mass protostar IRAS16293-2422 towards which interstellar deuterated hydroxyl OD has been detected is marked with a red circle. The absorption line spectrum, observed with GREAT onboard SOFIA, displays the molecule’s fingerprint at a frequency of 1.3915 Terahertz (or 0.215 mm wavelength). The inset shows the OD molecule (red: oxygene, gray: deuterium), an isotopic substitute of hydroxyl (OH) with the hydrogen atom replaced by heavier deuterium. This deuterated molecule is an important marker in the formation of interstellar water and may serve as a chemical clock in the early star formation process.The bright yellowish star in the bottom left is Antares, one of the brightest stars in the sky. Below and to Antares’ right is the globular cluster Messier 4.Credits: Spectrum: MPIfR/B. Parise, Photo: ESO/S. Guisard
SOFIA (Stratospheric Observatory for Infrared Astronomy) has been detected a new interstellar molecules. Not only that, the spectral lines important in space also successfully detected. These observations carry information about the various stages in the process of star formation. SOFIA using the German Receiver for Astronomy at Terahertz Frequencies (GREAT) in this observation.

As a joint project between NASA and the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), SOFIA operates a 2.7-m telescope in a modified Boeing 747SP aircraft and is the world's largest ever airborne infrared observatory. SOFIA flies at altitudes as high as 13700 meters to provide access to astronomical signals at far-infrared wavelengths that would otherwise be blocked due to absorption by water vapour in the atmosphere. The SOFIA observatory and the GREAT instrument open the far-infrared skies for high-resolution spectroscopy, and GREAT pushes its technology to higher frequencies and sensitivities than ever reached before.

By using GREAT, scientists are now able to investigate the velocity field of gas in the parental molecular clouds. Velocity field is traced by the important cooling line radiation of ionized carbon in several star forming regions.

GREAT detected the velocity signature of infalling gas motion (“collapse”) in the envelopes of three protostars, directly probing the dynamics of a forming star. Two interstellar molecular species were detected for the first time ever: OD, an isotopic substitute of hydroxyl (OH) with the hydrogen atom replaced by the heavier deuterium, and the mercapto radical SH. Observations of the ground-state transition of OH at a frequency of 2.5 Terahertz (120 microns wavelength) explored new astrochemical territories while pushing the technological frontier.

The remnant envelope of an evolved star, ionized by its hot stellar core, was also investigated as was the violent shock interaction of a supernova remnant and the surrounding interstellar medium. Furthermore, the circumnuclear accretion disk, ultimately feeding the black hole in the centre of the Milky Way galaxy was studied, as well as star formation in the circumnuclear region of the nearby galaxy IC342.

“The rich harvest of scientific results from this first observing campaign with SOFIA and the GREAT instrument gives a first glimpse of the tremendous scientific potential of this observatory and promises unique astronomical observations for years to come, particularly in the topical research areas of star formation and astrochemistry” states the Deputy Director of the SOFIA Science Mission, Hans Zinnecker, from DSI. In parallel with Rolf Güsten from the Max-Planck-Institut für Radioastronomie, the Principal Investigator of the GREAT project, Zinnecker organized the selection process and ultimately selected some of the most exciting observing proposals from the German astronomical community.

“The high resolving power of the GREAT spectrometer is designed for studies of  interstellar gas and the stellar life cycle, from a protostar’s early embryonic phase when still embedded in its parental cloud  to an evolved star’s death when the stellar envelope is ejected back into space”, says Güsten. “This stunning collection of first scientific results is reward for the many years of development work, and underlines the huge scientific potential of airborne far-infrared spectroscopy.”

This story had edited by author of threelas
Source: Alphagalileo

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