For the first time ever, isotopes have been found in the atmosphere of an exoplanet. About a year ago, it was reported that multiple planets orbiting a sun-like star had been photographed for the first time ever. The photograph was taken by the European Southern Observatory’s Very Large Telescope (or VLT) in Chile and showed two massive planets orbiting a young sun-like star named TYC 8998-760-1. (The picture can be seen here.)
The system, which is located about 300 light-years away from us, has two planets named TYC 8998-760-1b and c. TYC 8998-760-1b is approximately 14 times larger than Jupiter and orbits at an average distance of 160 astronomical units (AU), while TYC 8998-760-1c is around 6 times bigger than Jupiter and orbits at a distance of 320 AU (one AU is the average distance of Earth to our sun).
And now, scientists have made another fascinating discovery regarding TYC 8998-760-1b as they have made the first ever detection of isotopes in the atmosphere of an exoplanet. Astronomers found a type of carbon called carbon-13 in the haze around the planet. They made this detection by using an instrument named the Spectrograph for Integral Field Observations in the Near Infrared (SINFONI) on the Very Large Telescope.
The team noticed that wavelengths of light that were absorbed by the planet were consistent with carbon-13 (possibly wrapped up in carbon monoxide gas). The most common stable carbon isotope is carbon-12 with six protons, six neutrons, and six electrons; however, carbon-13 contains seven neutrons. And the fact that they found twice the expected amount of carbon-13 in TYC 8998-760-1b’s atmosphere is astonishing and may provide experts with valuable information regarding how the planet formed.
Paul Mollière, who is an astrophysicist at the Max Planck Institute for Astronomy in Germany, explained this in further detail, “The planet is more than one hundred and fifty times farther away from its parent star than our Earth is from our Sun,” adding, “At such a great distance, ices have possibly formed with more carbon-13, causing the higher fraction of this isotope in the planet's atmosphere today.”
The area in which the planet would have formed would be located past the carbon monoxide snow line – this is where carbon monoxide condenses and freezes into ice from gas because of the distance it is from the warmth of its star. To put this into better perspective, Neptune and Uranus have more deuterium (a hydrogen isotope with one proton and one neutron) than Jupiter because they formed past the water snow line.
As for what to expect now that this groundbreaking discovery has been made, astronomer Ignas Snellen from Leiden University said, “The expectation is that in the future, isotopes will further help to understand exactly how, where and when planets form.” “This result is just the beginning.” The study was published in Nature where it can be read in full.
An image of what TYC 8998-760-1b may look like can be seen here.