New Techniques Weighs Mass of Exoplanets

Ever since the first exoplanet Tau Bootis b was discovered,  which still remains one of the closest exoplanets known, the scientist have constantly been on a go to develop new strategies to measure the planets exact mass. 

These attempts end as an international team has come up with up a remarkable invention. López-Morales, along with her colleagues Florian Rodler and Ignasi Ribas of the Institute of Space Sciences, ICE has for the first time determined the mass of a non-transiting planet using a new technique that involves studying the carbon monoxide signature of the planet's atmosphere.

Team member Ernst de Mooij, a postdoctoral fellow in the University of Toronto's Department of Astronomy and Astrophysics says, "The problem with exoplanets is that in general we do not know the orientation of their orbit as we see them from Earth. This prevents us from getting a good determination of their masses. However, with our new technique we were able to measure the motion of Tau Bootis b, from which we have determined that it orbits its host star at an angle of 44 degrees as seen from the Earth, and that the planet is six times the mass of Jupiter."

Tau Bootis b was one of the first exoplanets to be discovered back in 1996, positioned in the constellation of Bootes, and it orbits a star about 50 light-years from Earth that's bright enough to be visible to the naked eye. Similar to Jupiter in size with a closeness of 8 stella radii, the light year for the planets lasts for just 3.3 eearth days. And also the surface temperature reaches to 1500 degree celcius thereby not supporting life.

The team had conducted a five hours of observations at near infrared wavelength (2.3 microns). They managed to collect data from the high-resolution spectrograph CRIRES, an instrument that is mounted on one of the four 8.2m Very Large Telescopes (VLT) of the European Southern Observatory (ESO) in Chile. The observations made confirmed the presence of carbon monoxide in the planet's atmosphere. In addition, by studying the planet's orbital motion through the displacement of spectral lines of carbon monoxide, the team was able to calculate its exact mass 5.6 times Jupiter  a first using this particular method, and also a first for a non-transiting planet.

This new technique is definitely one of the strong advances ever made in the field of exoplanets.