What is a Planet? Science in the Pub Number 71 Part of Astronomy on the Go! With panellists Penny Sackett, Pat Roche, Chris Tinney and Gibor Basri Compered by Fred Watson Wednesday, July 23rd 2003, 7:00pm Harlequin Inn, Pyrmont Must planets exist around a star, or are there "free-floating" planets? What's the difference between a "brown dwarf" and a "hot Jupiter"? Is there a difference in origin or is this just a matter of semantics? Designed for a professional audience, the delegates of the International Astronomical Union General Assembly, taking place in the Sydney Convention Centre this week. Guests include Penny Sackett, director of the Mount Stromlo Observatory (Research Centre for Astronomy and Astrophysics at the ANU), Chris Tinney of the Anglo Australian Observatory, Pat Roche from Oxford University and Gibor Basri of the University of California at Berkeley. Compered by Fred Watson. Penny Sackett was appointed Director of ANU's Research School of Astronomy and Astrophysics and the Mount Stromlo and Siding Spring Observatories in 2002. When not occupied with putting out the fires, administrative and otherwise, often associated with that post, Sackett pursues her other major professional interests of extrasolar planets, dark matter, galactic structure, planetary science, Extremely Large Telescopes, and science communication and administration. Sackett took her PhD in theoretical physics from the University of Pittsburgh, and has held positions at Amherst College (USA), the Institute for Advanced Study (Princeton, USA), and the Kapteyn Astronomical Institute (Netherlands). She has served on Australian, Dutch, European, and US science and advisory panels, including several committees for Next Generation Telescopes. Her career also includes science reporting for Science News magazine and program administration for the US National Science Foundation. For seven years, Sackett served as Principal Investigator of the international PLANET microlensing collaboration, using telescopes around the world, including three in Australia. Some of her most memorable research moments include determining the shape of things: that are unseen (dark matter halos) or 200,000 light years distant (star in Small Magellanic Cloud) or yet to come (partial eclipses of extrasolar hot Jupiters). Pat Roche is an astronomer at the University of Oxford in the UK, where his day job is to tutor physics students. He arrived in Oxford to work on a proposal for the UK to join an 8-m telescope project in 1989 on a 2 year secondment from his research fellowship at the Royal Observatory Edinburgh; that short secondment extended and became long term as the proposal became a reality and the Gemini observatory was built and commissioned. Pat was the UK Gemini project scientist from 1996-2002. He spent 4 years at the Anglo-Australian Observatory in Epping in the 1980s where he developed an appreciation of Australian life and Coopers Sparkling Ale, before returning to the UK. His research concentrates on studies of the interstellar medium and the nature and constituents of cosmic dust. He mostly uses the infrared wavebands to detect the elusive signatures of dust grains and molecules in the embers of dying stars and the nurseries of star-forming molecular clouds. Interstellar dust probably has a consistency like smoke particles rather than sooty or sandy grains, so maybe the dinosaurs were finished off by the effects of passive smoke rather than a big bang from a marauding asteroid or comet. Pat believes that the easiest way to make new discoveries is to try something new. The alternatives are to think deeply and to be smart, which are much harder. He has therefore has been involved in many novel infrared instruments, including mid-infrared spectrometers and near-infrared cameras for telescopes in Hawaii. Gibor Basri has been in the Astronomy Dept. at the Univ. of California, Berkeley for more than 20 years. He is primarily an optical spectroscopist, with periodic excursions to short wavelengths using various space observatories. His research ranges widely in the stellar domain, but is unified by an interest in magnetic fields on low mass stars. He has worked extensively on the star-formation problem, and onstellar activity. For the past decade there has been an emphasis on very low mass stars and brown dwarfs. As he ages, he drifts to ever lower masses. Now he is studying objects below the fusion limit (which he calls "planemos"). He is gearing up for NASA's Kepler mission, which will search for terrestrial planets around other stars (those stars will be solar-type, and magnetic activity will still be an important aspect of what he sees in them). In addition to his research, Gibor has been active in the area of science education, especially for underrepresented populations in the USA. He has written a few popular articles, and lectured extensively. He serves on the Board of Oakland's Chabot Space and Science Center. When looking to get away from it all, he is generally found hiking the (US West) outback, or skiing down double-black-diamond slopes. Chris Tinney is Head of Astronomy at the Anglo-Australian Observatory. He has also been involved in a number of other instrumentation projects, such as a recently developed wide-field imager for the Anglo-Australian Telescope. Chris did an Honours degree in physics at the University of Sydney, then headed overseas to do his PhD at Caltech (California Institute of Technology). Following this he went to the European Southern Observatory. After working in Garching, Germany (with frequent shuttling to ESO's observatory in Chile) he returned to Australia to take up a position as Research Scientist with the Anglo-Australian Observatory. Chris spends a lot of his research time working on the Anglo-Australian Telescope's hunt for planets around other stars. This long-term program has been extremely successful, having netted 13 extra-solar planets to date. Chris also studies "brown dwarfs" - stars that don't quite make the grade. These intriguing objects were found only in the last ten years. Chris has been able to show that these smouldering cinders actually have a kind of "weather" going on in their atmospheres. Our compere tonight is Fred Watson is familiar to Science in the Pub fans as both a speaker and a compere. He is astronomer-in-charge of the Anglo-Australian Observatory at Coonabarabran in north-western NSW, and an adjunct professor in the University of Southern Queensland and the Queensland University of Technology. He is a well-known broadcaster and writer on astronomical topics. His new book on the history of the telescope will be published next year by Allen and Unwin. Gibor has provided his poem as a circular argument: Science in the Pub™ is the Eureka Award winning endeavour in science communication. Regular sessions are generally staged 3-4 times per year, (generally 7-9pm on Wednesdays) at the Harlequin Inn, 152 Harris Street, Pyrmont in Sydney. Admission costs $5 worth of raffle tickets, your chance to win one of many excellent prizes! Visit our website at http://www.scienceinthepub.com/. Next Science in the Pub session
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