Astronomers have discovered two Super-Earths orbiting the nearest star

(ORDO NEWS) — Two new worlds have just been discovered, believed to be made of rocky minerals, orbiting a star close to our cosmic neighborhood.

These two newly discovered exoplanets are what are known as super-Earths. but smaller than the ice giant orbiting the cool red dwarf HD 260655, which is only 33 light-years away.

While the worlds are unlikely to be habitable given our current understanding of life, the star and its exoplanets are among the closest multi-world systems to Earth.

This makes it an excellent target for future studies to try to understand what exoplanets are made of and evaluate their atmospheres. an attempt that will help us in the search for extraterrestrial life, even if the two worlds are unable to accept it themselves.

“Both planets in this system are considered among the best objects to study the atmosphere because of the brightness of their star,” says astronomer Michelle Kunimoto of the MIT Kavli Institute. for astrophysics and space research.

“Is there an atmosphere rich in volatile substances around these planets? And are there signs of aquatic or carbonaceous species? These planets are fantastic testing grounds for such research.”

To date, over 5,000 exoplanets have been confirmed in the Milky Way, and astrobiologists are deeply interested in discovering terrestrial or rocky worlds such as Earth, Venus, and Mars.

We have a sample of exactly one world that is known to have life – ours, so finding planets similar to Earth in size and composition is one of the main criteria in the search for life elsewhere. galaxies.

Rocky exoplanets, however, are relatively small in size and mass, making them difficult to detect; most of the exoplanets we’ve been able to measure to date tend to fall into giant rocky worlds, or better yet, neighboring rocky worlds are in high demand.

The two worlds orbiting HD 260655, named HD 260655 b and HD 260655 c, were discovered because they pass between us and their star. during their orbit. The faint dips in starlight due to these exoplanetary transits have been recorded by NASA’s TESS exoplane telescope, designed to detect just such phenomena.

When Kunimoto noticed these transit gaps in the TESS data, the next step was to find out if the star had appeared in previous surveys. and it was.

The high-resolution Echelle spectrometer at the Keck Telescope (now known as ANDES) had publicly available data dating back to 1998. Another spectrometer, CARMENES at the Calar Alto Observatory in Spain, also recorded stars.

This has huge implications for exoplanet science: spectrographic data can show whether a star is moving in place or not.

“Each planet orbiting a star is going to have a slight gravitational pull on its star,” says Kunimoto. “We are looking for any subtle movement of this star that could indicate that it is being pulled by a planetary-mass object.”

Between the TESS data and the HIRES and CARMENES data, the team was able to confirm that two exoplanets orbit HD 260655. What’s more, with both datasets, the team was able to compile a complete profile of the two exoplanets.

The transit data provides a physical size based on how the star blocks out a lot of light; and the spectral data shows how massive the exoplanet is, based on how strongly the star is moving. Both datasets can be used to calculate the exoplanet’s orbit.

The inner exoplanet, HD 260655 b, is about 1.2 times the size of Earth and twice the mass of Earth, and orbits the star every 2.8 days. The outer world, HD 260655 c, is 1.5 times the size and three times the mass of Earth, and has an orbital time of 5.7 days.

With these sizes and masses, their densities suggest that the two exoplanets are likely to be rocky worlds.

Unfortunately, although the star is cooler and dimmer than the Sun, the planets’ proximity to HD 260655 means the worlds will be too hot for life as we know it.

HD 260655 b has an average temperature of 435 degrees Celsius (816 degrees Fahrenheit), while HD 260655 c has a milder but still scorching temperature of 284 degrees Celsius (543 degrees Fahrenheit).

“We believe this range is outside the habitable zone, too hot for liquid water to exist on the surface,” says Kunimoto.

However, both exoplanets may still have atmospheres that should be ripe for exploration with the recently deployed James Webb Space Telescope, which includes peering into exoplanet atmospheres among its mission targets.

What’s more, there may even be additional exoplanets orbiting the star that we haven’t yet discovered.

“There are many multi-planet systems containing five or six planets, especially around small stars like this one,” says astrophysicist Avi Sporer of the Institute for Astrophysics and Space Research. Kavli at the Massachusetts Institute of Technology. habitable zone. That’s optimistic thinking.”


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