A NASA sounding rocket will observe a nearby star to learn how starlight affects the atmospheres of exoplanets – key information in the hunt for life outside our solar system.
On its upcoming flight, SISTINE-2 will observe Procyon A, some 11.5 light-years away. Procyon A is an F-type star, which is slightly larger, hotter, and brighter than our Sun. Though it does not have any known exoplanets, studying Procyon A can help us understand F-type stars and their exoplanets throughout the universe.
“Knowing the ultraviolet spectra of these stars will help us find the most promising star-planet environments with future NASA observatories,” France said.
SISTINE-2 comprises a telescope and an instrument known as a spectrograph, which breaks light into its separate colors. SISTINE-2 will focus on ultraviolet light from 100 to 160 nanometers, a range that includes wavelengths known to produce false positive biomarkers. By combining their data with existing observations of X-ray, extreme ultraviolet, and visible light from other F-type stars, the team hopes to assemble a reference spectrum that will help astronomers interpret biomarkers on exoplanets orbiting F-type stars.
SISTINE-2 is also testing hardware. Before its 2019 flight, the team applied an enhanced lithium fluoride optical coating to the instrument’s mirrors to improve its UV reflectivity. The results some three years later help evaluate whether this specialized coating may be suitable for larger, longer-duration space missions.
As in its 2019 flight, the instrument will launch on a sounding rocket, a small suborbital rocket that makes brief observations in space before falling back to Earth. Ascending to an estimated altitude of about 174 miles (280 kilometers) to access ultraviolet light otherwise absorbed by our atmosphere, SISTINE-2 will observe Procyon A for about five minutes. The instrument will then fall back to Earth, descending by parachute for recovery and refurbishing.
The team hopes for a soft landing to aid in a quick turnaround to be ready for its third launch in July 2022, from the Arnhem Space Centre in Nhulunbuy, Australia. There, a refurbished SISTINE instrument will observe Alpha Centauri A and B, G- and K-type stars, respectively, similar to and slightly cooler than our Sun, and the closest such stars to us. This system is also home to Proxima Centauri, a cool red dwarf star orbited by the closest known exoplanet, Proxima B. These observations will add additional entries to the growing star catalog – small but critical steps in the search for life.