Exoplanets, Swiss Style

• By Faith Tucker
• July 16, 2010
• 3 Comments

Hemmed in on all sides by the heavyweights of Western Europe lies a rather curious country. After spending more than three months in this quadralingual, dairy-obsessed country, I’ve developed a deep fondness for Switzerland. But even I was surprised to find that there’s more to Switzerland than neutrality, fondue and chocolate. Buried beneath their exterior of private banking and cheese manufacturing, Switzerland claims a rich history of astronomy research and innovation that any country could be proud of.

The Matterhorn in Zermatt, Switzerland, photo credit: Faith Tucker

Over just the last few hundred years, many Swiss individuals have managed to distinguish themselves within the scientific world. Basel native Leonhard Euler (1707-1783) was a renowned mathematician who produced pioneering work in the areas of celestial mechanics and the movements of asteroids, comets, and spacecraft. (You might remember him from math class when your teacher wrote his famous Euler’s Formula, eix=cosx+isonx, on the board. You promptly pronounced it ‘Yooler’s’ Formula’ and with a deep sigh of frustration, your teacher corrected you saying, “It’s pronounce ‘Oiler’s Formula’!”) Einstein spent his miracle year of 1905 in Bern writing four monumental physics papers, which is further explored in my previous post “Annus Mirabilis”. And Marcel Golay, the director of the Geneva Observatory, initiated the conference in 1960 that would eventually result in the formation of the European Space Agency. In response to this movement to draw Europe into space exploration, the Swiss Parliament stated, “It is obvious that space research cannot be left as the exclusive domain of the United States and the Soviet Union… Europe, and Switzerland itself, would soon suffer the consequences.” Thus Switzerland propelled itself along with the rest of Europe into the Space Age.

The astute reader might mention that Switzerland’s current scientific clout arguably lies in it being the home of CERN (the European Organization for Nuclear Research) and its Large Hadron Collider, but that is a subject that deserves its very own post (check back in a few weeks). Though there are many exciting astronomy sites to be found in Switzerland, today we’ll be focusing on CERN’s lesser-known neighbor, the Geneva Observatory.

Over the years, the Geneva Observatory has grown out of humble origins to be an international center for astrophysical research. In 1772, young Swiss astronomer Jacques-Andre Mallet founded the Observatory in the center of what is now the historic Old Town of Geneva. Mallet was a thorough observer who used his many telescopes and timepieces (many of which can still be found in the Geneva History of Science Museum) to create detailed star charts and track the motion of celestial bodies across the sky. Around this same time Mallet made the long trek to Lapland to observe Venus’ transit in order to calculate the sun’s parallax. Through the years the Observatory traded hands and locations a number of times before finally settling in its modern location in the outskirts of Geneva in 1966.

Today the Observatory is shared between the University of Geneva Astronomy Department, the Astrophysics Laboratory of the Federal Polytechnic School of Lausanne and the ESA’s INTEGRAL Science Data Center. Between these three groups, research at the Geneva Observatory covers nearly every aspect of astronomy, including planetary systems, stellar evolution, stellar nuclesynthesis, galactic evolution & dynamics, quasars, gamma-ray busts and gravitational waves.

The above list, impressive and expansive as it may be, is just the backdrop that envelopes the crown jewel of the Geneva Observatory’s research. This sparkling achievement for which the observatory is best known began in 1995 when Michel Mayor, along with Didier Queloz, discovered 51 Pegasi b, the first extrasolar planet (also known as exoplanets) orbiting a sun-like star.

An artist’s conception of an exoplanet, Photo credit: NASA Jet Propulsion Laboratory

The shock waves that subsequently ripped through the astronomical community were a result of the initial excitement of finally finding evidence of an exoplanet as well as the unexpected nature of the planet. 51 Pegasi b has roughly the same size and mass as Jupiter, but, distinctly unlike Jupiter, it lies a mere .5 AU from its star, which would put it well within Mercury’s cozy orbit. This unique planet became the archetype of a new breed of planets that resembles Jupiter but who orbits seemingly impossibly close to their star, aptly named “Hot Jupiters.” These bizarre planets challenged astronomers’ theories and understanding of planetary formation and evolution, forcing them to reevaluate how such a massive, gaseous planet could possibly be stable living so close to their star. After all, what fun would science be if we weren’t wrong and hopelessly confused every once and a while?

Since 1995, astronomers around the world have continued their ceaseless hunt for exoplanets and sought to further refine their understanding of these distant Earths. Michel Mayor and the Geneva Observatory added another valuable piece to the developing puzzle of exoplanets in 2009 with the discovery of Gliese 581 e. This exoplanet is the smallest yet to be discovered at 1.9 earth masses and most similar to our own humble planetary abode, but its orbit lies just outside the habitable zone (the orbital band around a star where life could potentially develop). What’s more, in the same study Mayor and his team determined that another planet in the Gliese 581 system, planet ‘d,’ is located within the star’s habitable zone. Although it is too massive to be rocky like earth, its attributes make it “the first serious ‘water world’ candidate,” according to team member Stephane Udry.

Another artist’s conception of an exoplanet, Photo credit: Cal Tech

Between the discoveries of 51 Pegasi b and the Gleise 581 system, I think it’s fair to say that the Geneva Observatory has carved their name into the history of the burgeoning field of exoplanets, and astronomy in general, forever. Along these lines, Genevan astronomer and Swiss Coordinator for the International Year of Astronomy, Pierre Dubath, remarked to me that Mayor’s 1995 discovery particularly gave the Geneva Observatory, and Switzerland as well, a strong reputation and an invaluable place in the astronomy community. Vive la Suisse!

Although the Geneva Observaotry has seen great success in their exoplanet hunting, it is far from the only team engaged in this interstellar safari. NASA’s Kepler mission launched in March of 2009 and embarked on a 3.5 year-long mission to discover exoplanets.

NASA’s Kepler satellite and the patch of sky it will be observing, Photo credit: NASA Goddard Space Flight Center

The satellite is using the transit method of exoplanet detection in which it spots a decrease in a star’s apparent brightness as a planet in orbit passes directly between the star and the observer. Kepler’s confirmed exoplanet count is at five now, but earlier this June they released 43 days of science data that includes a set of 400 objects of interest to be studied further. With so much new data and more coming in each day, Kepler is sure to turn out some fascinating findings!

The light emitted by a star will dip as a planet transits in front of it, Photo credit: NASA Kepler

Last summer, I had the opportunity to visit Kepler’s headquarters at NASA’s Ames Research Center in my hometown of Mountain View, CA. The 28-member team there is working feverishly to sift through the enormous amounts of data Kepler is sending back to them from a small swath of sky between the Cygnus and Lyra constellations. I couldn’t help but get giddy with excitement about what new wonders this powerful satellite would reveal as I watched a room full of computers downloading and processing data. Remember to keep your eyes open for more news from Kepler’s exciting work in the coming months and years!