by Zakutnyaya Olga
Moscow (Voice of Russia) May 15, 2012
Light coming from an exoplanet only eight times larger than the Earth was observed with the help of NASA's Spitzer Space Telescope.
With the advent of new space and Earth-based devices, the study of exoplanets has become more intensive and competitive than ever. Even though no 'entrance fee' is required to enter the space race, Russia still considers exoplanet research as a potential, rather than real, prospect.
The planet under close scrutiny is orbiting a star in the Cancer constellation and is called 55 Cancri e, since its star has four other planets. Exoplanet 55 Cancri e faces its star, 55 Cancri A, whose temperature exceeds 2000 Kelvin, with only one side, and takes a little less than 18 hours to complete an orbit.
As the star is relatively close to our Solar System (55 Cancri A can be observed with naked eye), and the planet's position is convenient for observation, the planet was chosen as a promising target for further studies. The study was performed by an international team of researchers with the help of the Spitzer Space Telescope. The results will be published in the Astrophysical Journal.
While preliminary observations studied the planet as it passed in front of its star, thus affecting the appearance of the latter, a new study was aimed at the planet's composition. Therefore researchers tried to detect infrared light coming from the planet itself.
Collected data were interpreted and revealed evidence that 55 Cancri e most likely has a rocky core enveloped in an extremely thin atmosphere, that does not allow the heat from the sun-facing side to be transferred to the other side. It might also be covered by water in a so-called 'super-critical' state, which is both liquid water and gas.
Such observations can also prove useful as they allow the orbit of the planet to be defined more accurately and therefore helping make assumptions about its internal structure. For example, tidal forces can lead to extensive volcanism that might be supporting the atmosphere of the planet.
The work performed by researchers paves the way for further, more detailed studies of exoplanets. While Spitzer, launched nearly a decade ago (in August 2003), was primarily used for studying radiation from hot 'Jupiters' (gas giants that are very close to their host stars), a new generation of telescopes, the James Webb Space Telescope being the first to name, might bring a wealth of data on emissions from super-Earths, or much smaller rocky planets comparable to the Earth.
Although they frequently say that the technique applied in the current research can be used to detect signs of life on other planets, studies of the overall structure and composition of alien worlds are no less promising for their own sake, since they can help one to understand the formation of planetary systems around stars.
The study and discovery exoplanets evolves rapidly. More than 750 planets outside the Solar System have been found since 1992 (to name only confirmed ones).
Even more are promised by the continued operation of NASA's Kepler observatory, specially dedicated to search for extrasolar planetary systems, that led to wave of new exoplanets (accounting for thousands since its launch in 2009) discovered on a routine basis.
However, since we know that there are other planets outside of our Solar System, it is not enough to find a new one, but rather to obtain its detailed characteristics and to find a rather peculiar planet.
Therefore it is of utter importance that new instruments possess high sensitivity since the objects being studied are extremely far and faint (strictly speaking, the telescopes do not detect planets themselves, but rather their effects on the host star, thus making the task even more complicated).
The search for life or planets capable of sustaining life is only part of the task, since no one really knows how life can manifest itself. It would be more precise to say that studying other planetary systems brings us closer to understanding the way planets evolve and whether there are common laws for planetary formation.
Up until now only few planetary systems have been found that resemble our own Solar System, where gas giants orbit the Sun in the outer regions and small rocky planets - in the inner regions. Suprisingly, we see the contrary: gas giants that seem to like form near their stars, thus shattering earlier theories on the origin and evolution of planetary systems.
The study of exoplanets was one of the space exploration development strategies specified by the Federal Space Agency. According to the document, other planetary systems are to be studied from a period lasting till 2030.
As there are no specific details on the plan, one is left to speculate what actual steps will be taken to actually carry out these studies. As for now, Russia does not have observatories specifically dedicated to the task, and it is unlikely that there will be any, since the history of other space instruments, such as Spitzer or Kepler, counts several decades from initial idea to the actual design.
Probably, there might be some kind of program that will use Earth-based facilities, but its specific structure is unclear. Furthermore, as technology and data processing methods develop rapidly, the task to study other planets might become kind of a routine by the end of 2020's. To stay in trend, one is better to start today.
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