ESA’s Herschel Space Observatory has revealed the chemical fingerprints of potential life-enabling organic molecules in the Orion Nebula, a nearby stellar nursery in our Milky Way galaxy. This detailed-spectrum, obtained with the Heterodyne Instrument for the Far Infrared (HIFI) - one of Herschel's three innovative instruments - demonstrates the gold mine of information that Herschel-HIFI will provide on how organic molecules form in space.

The spectrum, one of the first to be obtained with HIFI since it returned to full health in January 2010 following technical difficulties, clearly demonstrates that the instrument is working well. Striking features in the HIFI spectrum include a rich, dense pattern of “spikes”, each representing the emission of light from a specific molecule in the Orion Nebula. This nebula is known to be one of the most prolific chemical factories in space, although the full extent of its chemistry and the pathways for molecule formation are not well understood. By sifting through the pattern of spikes in this spectrum, astronomers have identified a few common molecules that appear everywhere in the spectrum. The identification of the many other emission lines is currently ongoing.

Long caption: The HIFI spectrum of the Orion Nebula, superimposed on a Spitzer image of Orion. A characteristic feature is the spectral richness: among the organic molecules identified in this spectrum are water, carbon monoxide, formaldehyde, methanol, dimethyl ether, hydrogen cyanide, sulphur oxide, sulphur dioxide and their isotope analogues. It is expected that new molecules will also be identified. This spectrum is the first glimpse at the spectral richness of regions of star and planet formation. It harbours the promise of a deep understanding of the chemistry of space once the complete spectral surveys are available (ESA, HEXOS and the HIFI consortium)

“This HIFI spectrum, and the many more to come, will provide a virtual treasure trove of information regarding the overall chemical inventory and on how organics form in a region of active star formation. It harbours the promise of a deep understanding of the chemistry of space once we have the full spectral surveys available,” said Edwin Bergin of the University of Michigan, principal investigator of the HEXOS Key Programme on Herschel.

Unprecedented high resolution
HIFI was designed to provide extremely high-resolution spectra and to open new wavelength ranges for investigation, which are inaccessible to ground-based telescopes. “It is astonishing to see how well HIFI works," said Frank Helmich, HIFI principal investigator of SRON Netherlands Institute for Space Research. "We obtained this spectrum in a few hours and it already beats any other spectrum, at any other wavelength, ever taken of Orion.

The HIFI spectrum of water and organics in the Orion Nebula, with blow outs

The spectrum was obtained only one month after HIFI resumed operations on-board Herschel. In August 2009, HIFI experienced an unexpected voltage spike in the electronic system, probably caused by a high-energy cosmic particle, resulting in the instrument shutting down. The mission team studied the problem and developed a solution that prevents harmful side-effects of this type of event. On 14 January, 2010, HIFI was successfully switched back on using its spare electronics and restarted a sequence of testing and verification, ahead of science observations commencing on 28 February. It now rejoins the other two Herschel instruments, SPIRE and PACS, in their exploration of the far-infrared Universe.

Sophisticated databases
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia, with important participation from NASA.HIFI, a high resolution spectrometer was designed and built by a nationally-funded consortium led by SRON Netherlands Institute for Space Research. The consortium includes institutes from France, Germany, USA, Canada, Ireland, Italy, Poland, Russia, Spain, Sweden, Switzerland, and Taiwan.

Identification of the many spectral features visible in the Orion spectrum with transitions of particular molecular species requires sophisticated molecular spectroscopy databases, which collect the results from many years of laboratory spectroscopy work. The assignments for this HIFI spectrum were made using the Cologne Database of Molecular Spectroscopy (CDMS) and an equivalent database maintained at NASA’s Jet Propulsion Laboratory.

This HIFI spectrum was obtained for the Herschel HEXOS Key Programme – a scientific investigation using the Herschel HIFI and PACS instruments to perform full line surveys of five sources in the Orion and Sagittarius B2 molecular clouds. The scientific rights of these Herschel observations are owned by the HEXOS consortium, led by E. Bergin (University of Michigan).

Additional information
For more information please contact dr. Frank Helmich, principal investigator for HIFI, tel. 06-49423644, mail This email address is being protected from spam bots, you need Javascript enabled to view it , or drs. Frans Stravers, spokesman of SRON, tel. +31 (0)88 777 5892 /06-52679395, mail This email address is being protected from spam bots, you need Javascript enabled to view it