Twenty-five years ago, astronomers discovered a new class of exoplanet unlike any in our Solar System; hot Jupiters. These are gas giants that orbit their host star at distances hundreds of times closer than Jupiter (and other gas giants in our Solar System) around our Sun.
Using an instrument developed at Yale University, astronomers have been able to look into the particularly scorching skies of one such planet, located over 450 light-years from Earth. From spectral “fingerprints,” they were able to determine the existence of vaporized metals in the planet’s atmosphere. Ultimately, the researchers hope that their findings will help to broaden our understanding of how planetary systems form, and aid our search for habitable planets.
With temperatures measuring in at more than 1,730°C (3,140°F), MASCARA-2 b’s atmosphere graduates the planet to an ultra-hot status. Lying 100 times closer to its star than Jupiter’s orbit to our Sun, MASCARA-2 b orbits its host star every 3.47 days. For the researchers, this exoplanet was the perfect candidate to test the relatively new Extreme Precision Spectrometer (EXPRES), found at the Lowell Observatory Discovery Channel Telescope, Arizona.
Although the instrument’s main mission is to enable the detection of Earth-like planets around nearby stars, EXPRES’ extreme precision can be utilized to probe the atmospheres of distant planets.
“Atmospheric signatures are very faint and difficult to detect,” Sam Cabot, a graduate student in astronomy at Yale and leader of the study’s data analysis, said in a statement. “Serendipitously, EXPRES offers this capability, since you need very high-fidelity instruments to find planets outside our own Solar System.”
As described in the paper, accepted by the journal Astronomy and Astrophysics, when MASCARA-2 b aligns directly in between Earth and its host star, elements in its atmosphere block some of the starlight from reaching the ground-based telescope. By analyzing the specific wavelengths absorbed, the team was able to determine that gaseous iron, magnesium, and chromium resided in the exoplanet’s air.
A further look at the spectra obtained by EXPRES, suggested that MASCARA-2 b’s chemistry differs between the “morning” and “evening” sides of the planet.
“These chemical detections may not only teach us about the elemental composition of the atmosphere, but also about the efficiency of atmospheric circulation patterns,” Jens Hoeijmakers, lead author of the study and astronomer at the Geneva Observatory, explained.
As well as contributing to our knowledge of hot-Jupiters, the observations serve as a warm-up for future measurements by the EXPRES instrument that could dramatically advance the search for habitable exoplanets.
“Hot Jupiters provide the best laboratories for developing analysis techniques that will one day be used to search for biosignatures on potentially habitable worlds,” Professor Debra Fischer, co-author from Yale University and guiding force behind the instrument, said.
“The detection of vaporized metals in the atmosphere of MASCARA-2 b is one of the first exciting science results to emerge from EXPRES, more results are on the way.”