Thursday, March 19, 2009

SONG of the Stars

In the region of Canada that is now Quebec and Ontario, a Native American tribe known as the Algonquin developed a detailed myth about the annual path of the Big Dipper around the north celestial pole, which they chanted in their Song of the Stars: "We are the stars which sing, / we sing with our light; / We are the birds of fire, / we fly over the sky". Next week an international team of astronomers known as the SONG collaboration will gather in Denmark to discuss future plans for studying "stars which sing with their light".

The SONG collaboration is a Danish-led initiative to establish a global network of small telescopes to observe the subtle signatures of star-quakes that probe the interiors of distant Suns. The idea for SONG -- an acronym for Stellar Oscillations Network Group -- is based on the successful implementation of a similar concept deployed in the 1990's for observations of the Sun. The continuous oscillations that can be detected on the surfaces of the Sun and other stars require uninterrupted observations for long periods of time. The rotation of the Earth prevents a single telescope from being able to observe for such long periods without interruption. This limitation can be overcome by coordinating the observations of telescopes that are strategically located around the planet -- the star under investigation is always visible from somewhere, so a suitable network of telescopes can monitor any given star 24/7.

The Danish astronomers are among the world's leading experts on the observation and interpretation of star-quakes to deduce the internal structure and composition of stars like the Sun. Their motivation for establishing a global network of dedicated telescopes was driven by their frustration trying to conduct such observations with existing facilities. Obtaining time to use the telescopes at most observatories is a competitive process. Proposals are normally submitted 6 months to a year ahead of time, including a detailed scientific justification, and a typical allocation usually does not exceed 1 or 2 weeks. Since the proposals at different observatories are evaluated by independent time allocation committees, coordinating the observations from many telescopes is difficult to say the least. In the end, these logistical constraints were compromising the quality of the resulting observations -- so the Danes started looking for a better way to proceed.

With an initial grant from the Carlsberg Foundation, funded by the Danish beer company, they formulated a conceptual design that could accomplish their scientific objectives. Subsequent grants from public and private sources in Denmark will fund the construction of the prototype, which is scheduled to begin operating at an observatory in the Canary Islands by 2012. The purpose of the meeting next week is to coordinate with international partners who will seek their own funding to replicate the prototype and operate one of the telescopes in the network at their local observatory.

The Danes can't do it alone, but they have made it considerably easier to establish the network by doing much of the difficult work up front. This will certainly make it an easier sell to funding agencies and private foundations around the planet.