#astronomy New ESO observations present rocky exoplanet has simply half the mass of Venus – Astronotes

August 10, 2021 - Comment

A group of astronomers have used the European Southern Observatory’s Very Massive Telescope (ESO’s VLT) in Chile to shed new mild on planets round a close-by star, L 98-59, that resemble these within the internal Photo voltaic System. Amongst the findings are a planet with half the mass of Venus — the lightest exoplanet ever


A group of astronomers have used the European Southern Observatory’s Very Massive Telescope (ESO’s VLT) in Chile to shed new mild on planets round a close-by star, L 98-59, that resemble these within the internal Photo voltaic System. Amongst the findings are a planet with half the mass of Venus — the lightest exoplanet ever to be measured utilizing the radial velocity approach — an ocean world, and a attainable planet within the liveable zone.

“The planet within the liveable zone might have an environment that would defend and help life,” says María Rosa Zapatero Osorio, an astronomer on the Centre for Astrobiology in Madrid, Spain, and one of many authors of the examine revealed right this moment in Astronomy & Astrophysics.

This artist’s impression reveals L 98-59b

The outcomes are an vital step within the quest to seek out life on Earth-sized planets outdoors the Photo voltaic System. The detection of biosignatures on an exoplanet will depend on the flexibility to check its ambiance, however present telescopes usually are not massive sufficient to attain the decision wanted to do that for small, rocky planets. The newly studied planetary system, known as L 98-59 after its star, is a pretty goal for future observations of exoplanet atmospheres. Its orbits a star solely 35 light-years away and has now been discovered to host rocky planets, like Earth or Venus, that are shut sufficient to the star to be heat.

With the contribution of ESO’s VLT, the group was in a position to infer that three of the planets might include water of their interiors or atmospheres. The 2 planets closest to the star within the L 98-59 system are most likely dry, however might need small quantities of water, whereas as much as 30% of the third planet’s mass could possibly be water, making it an ocean world.

Moreover, the group discovered “hidden” exoplanets that had not beforehand been noticed on this planetary system. They found a fourth planet and suspect there’s a fifth, in a zone on the proper distance from the star for liquid water to exist on its floor. “We have now hints of the presence of a terrestrial planet within the liveable zone of this method,” explains Olivier Demangeon, a researcher on the Instituto de Astrofísica e Ciências do Espaço, College of Porto in Portugal and lead creator of the brand new examine.

This infographic reveals a comparability between the L 98-59 exoplanet system (prime) with a part of the internal Photo voltaic System (Mercury, Venus and Earth), highlighting the similarities between the 2.

The examine represents a technical breakthrough, as astronomers have been in a position to decide, utilizing the radial velocity technique, that the innermost planet within the system has simply half the mass of Venus. This makes it the lightest exoplanet ever measured utilizing this method, which calculates the wobble of the star attributable to the tiny gravitational tug of its orbiting planets.

The group used the Echelle SPectrograph for Rocky Exoplanets and Secure Spectroscopic Observations (ESPRESSO) instrument on ESO’s VLT to check L 98-59. “With out the precision and stability offered by ESPRESSO this measurement would haven’t been attainable,” says Zapatero Osorio. “This can be a step ahead in our capability to measure the plenty of the smallest planets past the Photo voltaic System.”

The astronomers first noticed three of L 98-59’s planets in 2019, utilizing NASA’s Transiting Exoplanet Survey Satellite tv for pc (TESS). This satellite tv for pc depends on a way known as the transit technique — the place the dip within the mild coming from the star attributable to a planet passing in entrance of it’s used to deduce the properties of the planet — to seek out the planets and measure their sizes. Nonetheless, it was solely with the addition of radial velocity measurements made with ESPRESSO and its predecessor, the Excessive Accuracy Radial velocity Planet Searcher (HARPS) on the ESO La Silla three.6-metre telescope, that Demangeon and his group have been capable of finding additional planets and measure the plenty and radii of the primary three. “If we wish to know what a planet is manufactured from, the minimal that we’d like is its mass and its radius,” Demangeon explains.

The group hopes to proceed to check the system with the forthcoming NASA/ESA/CSA James Webb House Telescope (JWST), whereas ESO’s Extraordinarily Massive Telescope (ELT), below building within the Chilean Atacama Desert and set to start out observations in 2027, may also be perfect for learning these planets. “The HIRES instrument on the ELT might have the facility to check the atmospheres of a few of the planets within the L 98-59 system, thus complementing the JWST from the bottom,” says Zapatero Osorio.

“This technique publicizes what’s to return,” provides Demangeon. “We, as a society, have been chasing terrestrial planets because the beginning of astronomy and now we’re lastly getting nearer and nearer to the detection of a terrestrial planet within the liveable zone of its star, of which we might examine the ambiance.”

Armagh Observatory and Planetarium astronomer Gavin Ramsay feedback, “Utilizing information from the TESS area satellite tv for pc, astronomers recognized three seemingly planets orbiting this low mass star since they produce dips within the stars flux as soon as each planet yr. This new work presents extraordinarily correct spectroscopic observations which reveal two extra exoplanets. These observations additionally gave the mass of every of the 5 planets, with the least large being half the mass of Venus. This stellar planetary system will assist astronomers perceive how planetary techniques evolve over time and can seemingly be noticed by future area missions comparable to JWST and Ariel to find out the composition of the planets atmospheres.”



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