Astronomers spy on three comets circling a nearby star

NASA's TESS spacecraft searching for exoplanets has spotted three comets in orbit around a star at 64 light-years away from the screen, according to a new document.

The comets of our own solar system are objects in solar orbit that develop a cloud and a tail from volatile elements when they receive enough solar energy. Scientists have already detected comet-like objects orbiting other stars, but these three are the first to be seen in the Transiting Exoplanet Survey Satellite (TESS) mission data. The results show the types of exciting discoveries that may arise from this relatively new mission, launched in April 2018.

The first author of the study, Sebastian Zieba, a master's student at the Austrian University of Innsbruck, analyzed the TESS observations of Beta Pictoris, a shining star well known in the southern sky. Scientists already knew that this star was interesting: it had an exoplanet and a carbon-rich disc. But the data revealed a strange hollow, a sign that something was passing in front of the star and attenuating its light.

But Beta Pictoris can be a difficult star to study, said Konstanze Zwintz, Zieba's advisor. "The star itself is oscillating," she explained. Its light glitters and, because of the luminous signal of the star, the researchers must understand it perfectly in order to determine the source of the gradation. The oscillating star and the gradation of the comet are incredibly weak.

"It's like you're on a mountain, light a candle and go to another mountain a mile away and watch the candle blink," Zwintz said. "The signals … are even smaller than that."

After taking into account the flickering of the star and taking into account any potential noise that TESS himself could introduce, there remained a signal like the capital V written in script: a net attenuation down, then a clearer clarification . It looked exactly like a prediction made two decades ago about what exocometes should look like, Zwintz explained. Then, looking more closely into the data, they found two more of these signals, according to the study published in Astronomy and Astrophysics.

Other researchers think it's cool too. "It was a prediction made twenty (20) years ago that Beta Pictoris would have observable exocomets. So it's extremely gratifying to see that this is indeed the case, "Jessie Christiansen, an astrophysicist at NASA's Exoplanet Science Institute at Caltech, told Gizmodo in an email. "And the data is really clean, which helps to make big claims like" exocomets! ""

Of course, this is an interpretation of a data set, and more data is needed to better understand what is happening. We do not really know how much they see the nucleus of the comet, the tail of gas and dust, and what is the density of all this. Let's hope that researchers will one day know what these exocometes are made of.

The work further demonstrates the power of the TESS mission and the many exciting things it can find outside our solar system.