To find life in other worlds, NASA will look at the light of a star
A NASA rocket will monitor a nearby star to find out how stellar light affects the atmosphere of extraterrestrials, which are important information for searching for life in space.
Using an updated tool that was first launched in 2019, the mission has a new goal: Procyon A, the brightest star in the Canis Minor galaxy.
SISTINE-2 (Exoplanet Host Stars near Suborpital Imaging Spectrograph for Transition Region Radiance) will have the first opportunity to launch from the White Sands missile range in New Mexico on November 8.
Answering the question of whether there is life anywhere else in the universe is fraught with technical challenges. We can no longer travel to the planets around other stars called exoplanets. Our telescopes are not powerful enough to see their surface either.
Instead, astronomers look at the atmosphere of an extraterrestrial and look for traces of chemicals associated with life. The so-called water, methane, oxygen, ozone and biomarkers create unique light patterns that telescopes can detect remotely. But to interpret them correctly, astronomers need to look at the planet’s star.
“The relationship between the planet’s atmosphere and the host star’s ultraviolet light determines which gases act as the best biomarkers,” said Kevin France, astronomer at Boulder University in Colorado and chief researcher on the mission.
Some ultraviolet (UV) wavelengths, for example, break down carbon dioxide and combine one oxygen atom with another to form molecular oxygen (made up of two oxygen atoms) or ozone (made up of three). Stars that emit enough light will create fake biomarkers on their planets and send astronomers to the wrong places.
The SISTINE team aims to avoid this dilemma by developing a guide for the wavelengths emitted by each type of star. There are different types of stars, and we do not yet have a complete picture of their light output or how it changes over time. Using the Starlight list, scientists can assess whether the detected biomarker is a possible sign of life or a false signal generated by an annoying starlight.
In its next flight, SISTINE-2 will observe Procyon A at a distance of about 11.5 light-years. Procyon A is an F-type star that is slightly larger, warmer, and brighter than our Sun. Although there are no extraterrestrials, studying Procyon A will help us understand the F-type stars and their orbits throughout the universe.
“Knowing the ultraviolet spectrum of these stars will help us find the most promising star-planet environments with future NASA observatories,” France said.
SISTINE-2 consists of a telescope and an instrument called a spectrograph, which separates light into its individual colors. SISTINE-2 is a range of wavelengths known to target false ultraviolet light from 100 to 160 nanometers, creating false positive biomarkers. The team hopes to gather a reference spectrum to help astronomers interpret biomarkers on exoplanets orbiting F-type stars by combining their data with visible light observations of existing X-rays, ultraviolet and other F-type stars.
Also tests SISTINE-2 hardware. Prior to its 2019 flight, the team applied an enhanced lithium fluoride optical coating to the instrument’s mirrors to enhance their UV reflectivity. The results, after about three years, help to assess whether this special coating is suitable for large and long space missions.
Five minute mission
Like its 2019 aircraft, the instrument will be launched on a probe rocket, a small auxiliary rocket that makes brief observations in space before returning to Earth. Climb to an altitude of approximately 280 km to access the ultraviolet light absorbed by our atmosphere and observe SISTINE-2 Procyon A for about five minutes. The instrument will then fall back to earth and the parachute will fall down for recovery and reconstruction.
The team expects a smooth landing from the Arnhem Space Center in Nhulunbuy, Australia to help make a quick turnaround ready for its third Eve in July 2022. There, the rearranged SISTINE instrument will monitor the alpha centaurians A and B, types G and K, respectively, similar to our Sun and slightly cooler and closer to us.
The system is orbited by Proxima Centauri, the cold red dwarf star Proxima B.