From phil@phil.Stanford.EDU Fri May 3 10:49:00 1996 Return-Path: Received: from phil.Stanford.EDU by quake.Stanford.EDU with SMTP (5.65/25-QUAKE-eef) id AA07388; Fri, 3 May 1996 10:48:59 -0700 Received: by phil.Stanford.EDU (940816.SGI.8.6.9/rsb-1.1) id KAA18063; Fri, 3 May 1996 10:48:58 -0700 From: "Philip Scherrer" Message-Id: <9605031048.ZM18061@phil.Stanford.EDU> Date: Fri, 3 May 1996 10:48:58 -0700 X-Mailer: Z-Mail (3.2.0 26oct94 MediaMail) To: margie@phil.Stanford.EDU Subject: (Fwd) FWD>RAS RELEASE- SOHO OBSE Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Status: R --- Forwarded mail from "David Salisbury" Date: 3 May 1996 09:25:06 -0800 From: "David Salisbury" Subject: FWD>RAS RELEASE- SOHO OBSE To: "Phil Scherrer@Physics" Mail*Link(r) SMTP FWD>RAS RELEASE: SOHO OBSERVATIONS Phil, FYI David -------------------------------------- Date: 5/3/96 9:09 AM From: STEPHEN P. MARAN Received: by news-service.stanford.edu with SMTP;3 May 1996 09:09:28 -0800 Received: by Forsythe.Stanford.EDU; Fri, 3 May 96 09:09:28 PDT Date: Fri, 3 May 1996 12:09:15 -0400 (EDT) From: "STEPHEN P. MARAN" To: rh.dfs@forsythe.stanford.edu Message-Id: <960503120915.22c006a0@ECLAIR.GSFC.NASA.GOV> Subject: RAS RELEASE: SOHO OBSERVATIONS THE FOLLOWING RELEASE WAS RECEIVED FROM THE ROYAL ASTRONOMICAL SOCIETY, IN THE U.K., AND IS FORWARDED FOR YOUR INFORMATION. WE REGRET THAT AN EXTENDED INTERRUPTION IN OUR INTERNET CONNECTION LED TO LATE FORWARDING OF A FEW RELEASES, INCLUDING THIS ONE.. Steve Maran, American Astronomical Society Embargoed for release 2 May 1996 Ref. PN 96/17 Issued by Dr Jacqueline Mitton RAS Public Relations Officer Phone: (0)1223-564914 FAX: (0)1223-572892 E-mail: jmitton @ast.cam.ac.uk and Peter Bond Space Science Advisor Phone: (0)1483-268672 Fax: (0)1483-274047 E-mail: 100604.1111@compuserve.com Space experiment logs 'weather' on the Sun The first results from the joint European Space Agency (ESA) and NASA SOHO (Solar and Heliospheric Observatory) spacecraft are being presented to the media at a Paris press conference on Thursday 2 May. Among those presenting new data will be Dr Richard Harrison of Rutherford Appleton Laboratory, Principal Investigator for the Coronal Diagnostic Spectrometer (CDS) experiment. CDS is a British-led experiment, built by a team from Rutherford Appleton in collaboration with the Mullard Space Science Laboratory in Surrey and institutes in the USA, Norway and Germany. The CDS project also includes solar physicists from the universities of Cambridge, Oxford, Birmingham and St Andrews, as well as the Armagh Observatory. The spectrometer studies the temperature, gas flow patterns and density of the Sun's outer regions. Although the Sun radiates light mainly in the visible region - which the eye can detect - it also radiates light we cannot see such as ultraviolet light and X- rays. CDS is designed to examine in detail how the Sun radiates in extreme ultraviolet radiation (150 to 800 Angstrom). This allows astronomers to detect characteristics in the radiation which are emitted by gases in the Sun's atmosphere, such as helium, neon, oxygen, nitrogen, and even iron, magnesium and silicon. By studying these signals it is possible to probe the Sun's atmosphere in detail - literally taking it to pieces. Different extreme ultraviolet signals can be compared to make temperature or density maps of the Sun's atmosphere. It is even possible to identify how the gases are flowing and what they are made of. In effect, CDS is allowing us to produce a kind of 'weather' map of the Sun's outer atmosphere - the corona - where the temperature soars to about 1 million degrees Celsius. CDS started solar observations on February 5th. Since then the team have studied in detail the extreme ultraviolet spectrum of the Sun and have started to build up maps of the corona. "We are seeing this atmosphere in a way which is totally new," comments Dr. Harrison. "We can take slices through the atmosphere and so build up the layers. We have even started to find rapid variations, where some layers in the Sun's atmosphere appear to change in tens of seconds while the layers above and below remain calm. The middle layer - a transitional region about 1,000-2,000 km above the Sun's visible surface - doesn't seem to care what the other layers are doing. "We have also found examples of jets of gas streaming through the atmosphere. The most extreme example found so far is travelling at around 450 km per second. These jets are trapped and being channelled along the magnetic field lines. " Studies such as these are important because there is still a lot we do not know about how the solar atmosphere works and how it influences us. The Sun occasionally ejects huge gas clouds and streams of energetic radioactive particles into space which travel at supersonic speeds towards the Earth. Occasionally, huge explosions occur in the Sun's atmosphere, many tens of times the size of the Earth, and these can produce enhanced levels of harmful radiation in, for example, the ultraviolet region. "With CDS, and its sister instruments on SOHO, we should soon begin to know better our star, the Sun, and its effects on our planet," says Dr. Harrison. SOHO was launched on 2nd December 1995. The space mission, which has taken almost a decade to develop, includes twelve experiments designed to study the Sun's core, its atmosphere, and its effects on the surrounding space. The spacecraft operates from a unique location in space, between the Earth and the Sun, at the so-called L1 Lagrangian point, where the gravitational pulls of the Sun and Earth form a balance. This way, the spacecraft can sit Sunward of the Earth with a continuous view of the Sun. The L1 point is 1.5 million km from the Earth. SOHO took about two and a half months to reach the L1 point, and during its 'cruise' phase the instruments were commissioned and tested. On February 14th a small burn inserted SOHO into its operating position. SOHO's nominal mission lifetime is two years, though scientists hope it will be extended to at least six years. UK scientists are involved in five other SOHO experiments. The University of Birmingham is collaborating on the LASCO (Large Angle Spectrometric Coronagraph). Professor Douglas Gough of Cambridge University is Co-Investigator on the GOLF, VIRGO and SOI experiments which are studying solar oscillations or 'sunquakes'. Scientists from Rutherford Appleton, Mullard Space Science Laboratory, Armagh Observatory, St Andrews, Oxford and Cambridge Universities are also working on data from the SUMER (Scanning Ultraviolet Spectrometer) experiment. SOHO is part of the International Solar-Terrestrial Science Programme and, with the four Cluster spacecraft scheduled for launch shortly, is a Cornerstone of ESA's Horizon 2000 long-term science programme. Together, they form a key part of the research programme of the Particle Physics and Astronomy Research Council (PPARC) with overall management and financial control being provided by Rutherford Appleton Laboratory. Contacts: Dr Richard A. Harrison, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0X11 0QX. Tel: (+44) (0)1235-446884. Fax: (+44) (0)1235-446509. E-mail: harrison@solg2.bnsc.rl.ac.uk Professor Douglas Gough, Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA. Tel: (+44) (0)1223-337548. Fax: (+44) (0)1223-337523. E-mail: dgough@mail.ast.cam.ac.uk Pictures are available from Dr. Harrison or the ESA press office in Paris (Tel: 33-1-5369-7155). Further information is also available on the RAL Worldwide Web page at http://star-www.rl.ac.uk/ssd.html ---End of forwarded mail from "David Salisbury"