Monday, December 20, 2010

Qatar leads the discovery of a new exoplanet

This is a weekly post by Nidhal Guessoum (see his earlier posts here). Nidhal is an astrophysicist and Professor of Physics at American University of Sharjah
Qatar has helped discover a new exoplanet, a “hot Jupiter” which has been called Qatar-1b, orbiting around the star 3UC311-087990, now dubbed Qatar-1, which lives some 550 light-years away from here. Qatar’s contribution has been in the form of an astronomer, Dr. Khalid Al-Subai, as well as some of the technical resources.
Dr. Al-Subai was in fact the leader of an international team of 22 scientists from 6 countries (Qatar, USA, UK, Germany, Spain, and Denmark). The instruments they used included a Qatar-supplied camera system, which was installed in New Mexico, USA. The Qatari side of the project was funded by the Qatar Foundation (QF), which mission is to support development in three social dimensions: education, scientific research, and community development (see QF’s Science and Research page here). Dr. Al-Subai himself is a research director at QF; see the webpage for his exoplanet-search project here.
Let me give some details about the search and the discovery before commenting on what I find significant in the project as a whole. The first phase consisted of images taken by the Qatari wide-angle 5-camera CCD imaging system (see image below) in New Mexico through most of 2010, whenever the night was clear.

Those images were then processed by some members of the team, including Al-Subai and colleagues of his at the Universities of St Andrews and Leicester, in the UK, bringing out a few hundred star candidates that showed some dipping in their luminosities. (The search used the “transit method”, where a planet going in front of its star will block some of the light coming to us, thus producing a slight and temporary “dip” in its luminosity.) The most promising candidates were then observed again, measuring the dimming more accurately with the KeplerCam instrument on the 1.2-meter-diameter telescope of the Whipple Observatory (Arizona) as well as using a different (spectroscopic) technique with the 1.5-m telescope at Whipple. And once the results indicated the presence of a planet around the star 3UC311-087990, additional observations were performed using two UK-based telescopes, the 1-meter Gregory Telescope at St Andrews and the 0.6-m telescope at Keele, to confirm the Qatar-1b transits as well as refine the orbital period and pin down the planet’s radius.
The star is of type K, a bit smaller and cooler than our Sun, of orange color, and is 550 light-years away, in the constellation of Draco, the Dragon. The planet orbits very close to the star, at only 6 stellar radii (compared to 215 solar radii for Earth and about 80 solar radii for Mercury, on average); it only takes 1.4 days (34 hours) to complete its orbit (compared to a year for Earth). These types of stars, which are the easiest exoplanets to find, are thus dubbed “hot Jupiters”. Moreover, in such orbital situations, the planet is largely expected to be “locked” with its star, taking the same time to rotate around its axis as it orbits around the star, like our Moon does, this being due to tidal forces which, over time, will have slowed the object’s rotation until “resonance” is established. This planet, like the Moon does with Earth, thus always presents the same side to the star it orbits around.
The paper giving the full technical details and other results of the search has been submitted to the highly regarded UK journal Monthly Notices of the Royal Astronomical Society; it is still in the refereeing stages; a preprint can be found here.
The team’s scientists are promising additional searches and discoveries, hopefully of greater importance, particularly smaller planets: “hot saturns”, “hot neptunes”, i.e. in the 10-20 range of earth masses, and perhaps even “cool earths” down the line, though for that to be achieved, other techniques will have to be used…
Though there have now been some 500 exoplanets discovered, a majority of them being of this “hot Jupiter” type, this is still a significant discovery, as evidenced by the submission of the paper to a major Astrophysics journal. Indeed, the more statistics and variety of cases we have, the better we will understand the conditions under which these worlds exist out there.
More importantly, however, as far as I see it, is the fact that such “pure research” has been funded and led by an institution and an astronomer from the Gulf. Oftentimes, research in this region is encouraged in the applied fields (“beneficial to society”), and though astronomy is liked and often discussed by people, I have rarely seen such support and push for research in this field.
Another important issue for me is the participation of researchers, scientists and students, from the region in such projects. It was great to see Al-Subai’s name at the top of the author list in the paper reporting the discovery in a prime journal, but in the future I will be even happier if I see colleagues from the region among the team members, and ecstatic if local/regional students were to take part in such research.


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