This month, two probe rockets will be launched from Australia, with experiments to determine whether the ultraviolet light emitted by the stars of the Alpha Centauri system is harmful to any potential life on the planets around them. The study will also reveal how typical (or abnormal) the sun is.
Alpha Centauri consists of two primary stars, Alpha Centauri A and Alpha Centauri B (which form a binary pair), as well as a third star, Proxima Centauri, which is only 4.3 light-years away. Although no planets have been positively detected around Alpha Centauri A or B, if any, the ultraviolet radiation from their stars can have a significant impact on whether or not they support life. .
Only the right amount of ultraviolet light can break down simple organic molecules, such as methane, causing molecular fragments to reform as more complex molecules needed for life. On the other hand, excess ultraviolet can dissociate water vapor, making it subject to being removed from a planet’s atmosphere by the solar wind and leaving the planet dry and arid, as Mars is today.
“Understanding ultraviolet radiation is extremely important to understanding what makes a planet habitable,” Brian Fleming, an astrophysicist at the University of Colorado, Boulder, said in a statement. Fleming is the lead researcher on one of the missions, the Dual Channel Extreme Ultraviolet Continuous Experiment (DEUCE). The other experiment launched with a probe rocket is called a suborbital imaging spectrograph for the irradiation of the transition region of the host stars of the nearby exoplanet (SISTINE). Sounding rockets fly in a parabolic trajectory, spending perhaps 20 minutes in space before re-entering the atmosphere, meaning each experiment will have little time to make observations.
Missions must be launched from the southern hemisphere because the Alpha Centauri system is not visible above a latitude of 29 degrees north, and only borders the horizon from Florida, while it is high in the sky seen from of Australia. SISTINE collects data at longer distant ultraviolet wavelengths, while DEUCE complements them by observing shorter extreme ultraviolet wavelengths, with some overlap between the two experiments so that the data can be calibrated and used as a data set. unique.
SISTINE was first launched on Wednesday (July 6) from the Arnhem Space Center in the Northern Territory of Australia. It was the second launch from the privately owned commercial space center after the launch in June of NASA’s quantum X-ray calorimeter. If all goes well, DEUCE will take off on July 12th. Each mission will travel a suborbital path to NASA’s two-stage Black Brant IX spacecraft.
Observing ultraviolet stars is difficult, because the ozone layer of the Earth’s atmosphere blocks ultraviolet light, forcing scientists to send ultraviolet telescopes into space. Meanwhile, the interstellar medium of gas and dust between the stars also absorbs ultraviolet light, so that any star at an appreciable distance cannot be observed very clearly in ultraviolet light.
As such, we have complete ultraviolet observations for only one star, the sun. But how typical are ultraviolet emissions from the sun? Astronomers don’t know it; they need ultraviolet readings from other stars to find out. Alpha Centauri A and B are good targets for the study, for two reasons. First, they are close, so their ultraviolet light is not dimmed by the interstellar medium. Second, they have sun-like masses and temperatures.
“Looking at Alpha Centauri will help us check if other stars like the sun have the same radiation environment or if there are a variety of environments,” said Kevin France, an astrophysicist at the University of Colorado, Boulder, and senior researcher at SISTINE . in the statement. The three spacecraft launches from the Arnhem Space Center are the first launches NASA has made from a commercial spaceport outside the United States. (NASA has already launched from Australia before, most recently, in 1995), but these rockets left the Royal Australian Air Force’s Woomera Range complex.)
“This range of commercial launches in Australia opens up new access to the night sky of the southern hemisphere, expanding the possibilities for future science missions,” Thomas Zurbuchen, associate administrator of NASA’s Scientific Mission Directorate, said in a statement. .
News summary:
- NASA probe rockets are launching to investigate Alpha Centauri
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