Helioseismology

The BiSON observatory at Carnarvon, Western Australia.

The Sun is the most important star in the sky - it dominates the solar-terrestrial environment and its behaviour has important consequences for our lives on Earth. The group in Birmingham has been studying the Sun since the 1960's and has built up decades of expertise. Members of the group are world leaders in the study of the Sun using its global acoustic modes of oscillation. Over the decades the group has been involved in many exciting aspects of solar science including:

The BiSON observatory at Narrabri, New South Wales, Australia.
  • The discovery and resolution of the solar-neutrino problem.
  • The solar magnetic activity cycle and its associated Space Weather.
  • The dynamo, or multiple dynamos, inside the Sun.
  • The ongoing solar abundance problem.
  • The quest for solar g-modes that would reveal the properties of the deep solar interior.

 

To observe the Sun, the group runs its own global network of automated robotic helioseismic observatories known as BiSON - the Birmingham Solar-Oscillations Network. BiSON consists of six remote sites, each of which supports a variety of complex, purpose-built instrumentation. These instruments observe the 'global' modes of oscillation that probe the deep solar interior. These data are widely regarded as being of unrivalled quality. Our instrumentation are based at the following sites:

The BiSON observatory at Las Campanas, Chile.
  • Mount Wilson, California, USA: this instrument was installed in 1992, and uses a small fraction of the beam from the 60-foot solar tower. It was initially installed on Haleakala in Hawaii in 1981 where it operated until 1991.
  • Las Campanas, Chile: Las Camapnas was commissioned in 1991. It is equatorially mounted and housed in a small dome. This site consistently produces the best BiSON data.
  • Izaña, Tenerife: Izaña is the longest running site of BiSON and has been producing data since 1975. Our station is situated at the Observatorio del Teide in a pyramid like building. It is operated under a collaboration with the I.A.C., and requires daily attention. Unlike the more recent stations, this spectrometer is not equatorially mounted. Sunlight is fed into the instrument using a coleostat - an arrangement of mirrors which change their orientations during the day to follow the course of the sun. The output beam is then reflected through a hole in the wall of the pyramid into the instrument.
  • Sutherland, South Africa: the instrument is installed in a dome situated at the South African Astronomical Observatory (SAAO) at Sutherland, Cape Province. It was commissioned in, and has been producing data since 1990.
  • Carnarvon, Western Australia: Carnarvon was the third BiSON site and was the first to have a spectrometer equatorially mounted in a dome. It was commissioned in 1985. The site is situated close to sea level, near to the Indian Ocean. BiSON shares this site with the buidling relics of an old satellite tracking station. 
  • Narrabri, New South Wales, Australia: Narrabri was commissioned in 1992 - this instrument is equatorially mounted and house in a small dome. The station is situated within the grounds of the ATNF's Paul Wild Observatory.

Data from the network, dating back to 1976, can be downloaded from the BiSON Open Data Portal. You can also view live system telemetry and images from the on-site cameras at BiSON Live!

BiSON images © S.J. Hale.