Wediscovered an Earth-sized exoplanet orbiting a red dwarf:Arewe alone?
We found an Earth-sized exoplanet orbiting a red dwarf star.
Red dwarfs, also known as M-type dwarfs, dominate the stellar populations of the Milky Way Galaxy and often last for more than 1000 billion years. These long-lived stars, which make up the majority of the stars in our galaxy, have the potential to host many planets.
Astronomers have examined a red dwarf star named Speculos 3, a Jupiter-sized star about 55 light years away, and discovered an Earth-sized exoplanet orbiting it. The planet is an excellent candidate for further research by the JAMES WEBB Space Telescope (JWST) and has been named SPECULOOS-3b.
SPECULOOS is an effort by observatories in Southern Europe to find Earth-like planets orbiting cool stars like red dwarfs, and the search for habitable planets eating superCoolStarsproject aims to find planets suitable for spectroscopy using JWST and VERY Large Telescope (ELT). Its unusual name pays tribute to the Belgian sweet biscuit.
The discovery of SPECULOOS-3b was presented in a recent paper in Nature Astronomy entitled “Detection of An Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3.”The lead author is Michael Gillon of the Astrobiology Research Unit at the University of Liège in Belgium.
Speculos is an automatic search using four telescopes: the Paranal Observatory in Chile, the Teide Observatory in Tenerife, the Lasila Observatory in Chile, and the Ukaimden Observatory in Morocco. The project is exploring 1,000 super cool stars and brown dwarfs for Earth-like planets.
Detecting planets around these stars is difficult due to their low luminosity, making it difficult to detect and study transit exoplanets. So far, astronomers have discovered only 1 well-known planetary system around these stars: the TRAPPIST-1 system. WHEN THE SPECULOOS PROGRAM BEGAN, IT WAS AIMED ATFINDINGATleast1SYSTEMSIMILAR TO TRAPPIST-12.
“We specially designedSpeculosto explore nearby super cool dwarfs in search of rocky planets,” Gillon said. “With thegreathelp of the Speculos prototype and the NASA Spitzer space Telescope, we discovered the famous Trappist-1 system. It was a great start.”
The darkness of these stars is important. “This particular red dwarf is more than 1,000 times brighter than the Sun, but its planet orbits much closer than Earth, heating the planet’s surface,” said co・author Catherine Clark, a postdoctoral researcher at NASA’s JPL in Southern California.
A new planet, an Earth-sized world, will orbit its star in just 17 hours.Starswith a spectral type of M6.5providethe planet with 16.5 timesmoresolar radiationthanthe Sun gives to the Earth. DESPITE BEING MUCH COOLER THAN THE SUN (5,772KCOMPARED TO2,900K OFTHE SUN), THE SHORT DISTANCE BETWEEN SPECULOOS-3 AND ITS PLANET CAUSES INTENSE IRRADIATION.
Sincetheplanet isprimarily infrared and the star is only the size of Jupiter, it isan exceptional candidate for follow-up observations, in line with the goals of theSpeculosProject,SpeculosProject1 has identified about 365 temperate, earth-sized targets for further research with JWST.
The SPECULOOS-3 system is about 6.6 BILLION years old. Its luminosity, mass, and radius are 0.084%, 10.1%, and 12.3% of the Sun’s luminosity, respectively. “SLIGHTLY LARGER THAN TRAPPIST-1, SPECULOOS-3 IS the 2nd SMALLEST MAIN SEQUENCE star found to host a PASSING PLANET,” the AUTHORS EXPLAIN IN their PAPER.
2 Different telescopes observed the passage of planets around the star in 2021 and 2022 over 8 nights. “Visual inspections of the light curve in 2021 and 2022 showed several transit-like structures motivated by intensive star monitoring in the future,” the authors explain. The star was re-observed in 2023.
The researchers determined that Speculos-3b is about the same size as the Earth and is about 96% of the planet’s radius. But the density and mass of the planet are not yet constrained. “Nevertheless, the author writes,” several factors strongly suggest a rocky composition.”
2 empirical reasons suggest that the planet is probably a rock. First, its radius is on the rocky side of the radius gap. Second, “All known earth-sized planets in the NASA exoplanet archive have masses that imply rock composition,” the authors explain.
The big problem concerns the planet’s potential atmosphere. “From a theoretical point of view, it is unlikely that such a small planet in such a short orbit maintained aconsiderableenvelope of hydrogen,asstrong extreme ultraviolet lightis emittedduring the early life of a low-mass star,” the authors explain.
The researchers looked for the 2nd planet around the star, but could not find it. They also spectroscopically examined the planet in ground facilities. We will have to wait for JWST to fully examine the planet’s atmosphere. The 2 most likely types of atmospheres for hot rocky planets are CO2 dominant and h2o dominant.
JWST can examine SPECULOOS-3b using luminescence spectroscopy (transmission spectroscopy), which can analyze light emittedfromplanetsandlight passing through the atmosphere. Luminescence spectroscopy is unaffected by the irregular stellar behavior commonly found in red dwarfs and helps determine surface mineralogy in the absence of an atmosphere. There is a wealth of potential information waiting to be discovered.
Source: Wediscovered an Earth-sized exoplanet orbiting a red dwarf:Arewe alone?
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Wediscovered an Earth-sized exoplanet orbiting a red dwarf:Arewe alone?