Caltech researchers found water on another planet.
Researchers at the California Institute of Technology (Caltech), in collaboration with several other institutions, have used a new technique to analyze the gaseous atmospheres of extra solar planets and have made the first detection of water in the atmosphere of a planet similar to Jupiter’s mass and orbiting the nearby star ‘Tau Bootis b’.
According to the authors of the study, published in The Astrophysical Journal Letters, further development and more sensitive instruments allow this technique will help researchers learn about how many planets similar to Earth and water have pointed exist within the Milky Way.
Had already been previously detected water vapor in a handful of planets, but these detections could only take place in very specific circumstances, explained one of the study leaders, Alexandra Lockwood. Specifically, you can get information when the planet transits or put in orbit in front of its parent star, or also if the world is far enough away from its star.
However, a significant part of the population of extrasolar planets does not meet any of these criteria, and no way to find information about the atmospheres of these planets. Seeking to resolve this problem, Lockwood and his team applied a new technique that uses radial velocity (RV) – commonly used in the visible region of the spectrum to which the eyes are sensitive – for discovering exoplanets that are not in transit.
Using the Doppler Effect, the detection of RV traditionally determines the motion of a star due to the gravitational pull of a planet companion. The star moves away from the orbital motion of the planet and the stellar characteristics change in wavelength direction. The closer the planet from its host star shows larger changes.
But in this case, Lockwood RV extended technique in the infrared to determine the orbit of ‘Tau Bootis b’ around its star, and added a new analysis of the light changes through spectroscopy – analyzing the spectrum of light – and since each compound emits a different wavelength, the firm of ‘unique’ light allows researchers to analyze the molecules that make up the planet’s atmosphere.
Using data from ‘Tau Bootis b’ obtained with the Near Infrared Echelle Spectrograph (NIRSPEC) Keck Telescope (Hawaii), the researchers were able to compare the molecular signature of water in the spectrum of light emitted by the planet, confirming the atmosphere effectively included steam.
“The information obtained from the spectrograph is like listening to an orchestra: if you listen carefully you can recognize a trumpet or a violin or a cello and can know that these instruments are present,” he pointed the researcher.
“With the telescope, the entire board is light, but the spectrograph can choose different parts, such as a wavelength of light that means there sodium or other means that there is water,” he added.
Besides using the spectrographic technique to study the atmospheric composition of the planet, the method also provides a new method for researchers to analyze the mass of the planets. “In fact two separate findings, but when you’re doing calculations to find the firm that determines the components of the atmosphere, it can also determine the 3D motion of the star and planet in the system. With this information, you can know the mass of the star and the planet, “he pointed Lockwood.
Although this new technique promises to increase the chances of scientists to look for water in extrasolar planets has limitations, according to some researchers. For example, the technique is currently limited to the so-called “hot Jupiter” gas giant planets such as ‘Tau Bootis b’ or those that are large and orbit very close to their parent star.
“The technique is limited by the power and range of length telescope gathering light wave, and even the site of incredible concentration Keck Observatory can only analyze hot planets orbiting bright stars,” acknowledged that the author says “When it better telescopes will also advance the art.”