Herschel confirms shortage of oxygen molecules in space

2012-03-27 by Robert Cumming

The Herschel Space Observatory has carried out the best measurements so far of oxygen molecules in space. The new measurements confirm the discovery by the satellite Odin in 2007 that there is far less molecular oxygen in interstellar space than astronomers had expected.

Cold interstellar clouds and stars near Rho Ophiuchi. Rings mark where Herschel saw traces of oxygen molecules. (Credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA)

– We’ve clearly shown that Odin’s detection was real, says René Liseau, astronomer at Chalmers, who led the study.

The international team, among them several scientists from Onsala Space Observatory and Chalmers, used the instrument HIFI onboard Herschel to detect signatures of oxygen molecules from interstellar clouds near the star Rho Ophiuchi, 400 light years distant.

They also looked for clues to why oxygen molecules are much rarer than expected in space.

- The mystery remains. So far we see no clear pattern which tells us why we see oxygen molecules in some places and not in others, says René Liseau.

A possible explanation is that oxygen molecules are formed only briefly during the lifetime of an interstellar cloud. That could explain why they have been so hard to find.

Contact: Robert Cumming, Onsala Space Observatory, tel +46 70 49 33 114, robert.cumming@chalmers.se, eller René Liseau, Onsala Space Observatory, tel +46 31 772 55 00, rene.liseau@chalmers.se

The research paper, “Multi-line detection of O2 toward rho Oph A” is scheduled for publication in the journal Astronomy & Astrophysics. It’s already available at http://arxiv.org/abs/1202.5637. The team is R. Liseau (Chalmers), P. F. Goldsmith (Caltech, USA), B. Larsson (Stockholm University), L. Pagani (Observatoire de Paris, France), P. Bergman (Onsala Space Observatory), J. Le Bourlot (Observatoire de Paris), T.A. Bell (Centro de Astrobiología, Madrid, Spain), A.O. Benz (ETH-Zürich, Switzerland), E.A. Bergin (Univ of Michigan, USA), P. Bjerkeli (Chalmers), J.H. Black (Chalmers), S. Bruderer (ETH-Zürich, Max-Planck-Institut für Extraterrestrische Fysik, Germany), P. Caselli (Univ of Leeds, UK), E. Caux (Univ of Toulouse, France), J.-H. Chen (Caltech), M. de Luca (Observatoire de Paris), P. Encrenaz (Observatoire de Paris), E. Falgarone (Observatoire de Paris), M. Gerin (Observatoire de Paris), J.R. Goicoechea (Centro de Astrobiología, Madrid), Å. Hjalmarson (Chalmers), D.J. Hollenbach (SETI Institute, USA), K. Justtanont (Chalmers), M.J. Kaufman (San José State University, USA), F. Le Petit (Observatoire de Paris), D. Li (NAO, Beijing, China; Caltech), D.C. Lis (Caltech), G.J. Melnick (Harvard-Smithsonian Center for Astrophysics, USA), Z. Nagy (SRON/Kapteyn Astronomical Institute, Netherlands), A.O.H. Olofsson (Onsala Space Observatory), G. Olofsson (Stockholm University), E. Roueff (Observatoire de Paris), Aa. Sandqvist (Stockholm University), R.L. Snell (Univ of Massachusetts), F.F.S. van der Tak (SRON/Kapteyn Astronomical Institute), E.F. van Dishoeck (Leiden Observatory, Netherlands and MPE, Germany), C. Vastel (Univ of Toulouse), S. Viti (UCL, UK), U.A. Yıldız (Leiden Observatory).