Signs of nuclear fusion inside a shiny new exoplanet

11 Jan. () –

Scientists have used the subtle movements of a distant star to discover a bright new exoplanet, showing signs of nuclear fusion in its core.

An international team of scientists, led by Professor Sasha Hinkley, from the University of Exeter, has detected a new exoplanet orbiting the star HD206893, which is about 750 trillion kilometers from Earth and is 30% larger than our Sun.

The researchers confirmed the existence of the distant planet using the GRAVITY instrument on the Very Large Telescope (VLT), which works using optical interferometry. to synchronize the VLT’s four main telescopes so that they function as a single, much larger telescope.

This technique allows GRAVITY to measure with extreme precision the position of the planet in its orbit, as well as to measure the spectrum of light emitted by the planet’s atmosphere, allowing astrophysicists to characterize its atmosphere.

The team of researchers has used this technique to come to the conclusion that the newly discovered planet clearly shows an obvious “brightness”, because it undergoes nuclear fusion by burning deuterium or “heavy hydrogen” in its core.

The discovery marks a breakthrough in the search for new distant worlds, as it is one of the first detections of a planet whose presence is partially inferred due to the astrometric motion of the host star as it moves across the sky.

The team believes that since ESA’s Gaia mission is expected to point the way to numerous such exoplanets, many will be able to be characterized by direct imaging, as in the case of this new discovery.

Professor Hinkley stated it’s a statement: “The discovery of HD206893c is a really important moment for the study of exoplanets, since ours may be the first direct detection of a ‘exoplanet Gaia'”.

Scientists originally discovered a brown dwarf, known as HD206893B, orbiting the host star in 2017. However, long-term monitoring by ESO’s HARPS instrument, as well as precise measurements of the host star’s proper motion by the Gaea Mission, they also hinted at the presence of an internal, lower-mass partner.

Using the GRAVITY instrument, the scientists were able to show that this companion was a new planet, called HD206893c, orbiting about 300 million miles from its host star – roughly halfway between the orbits of Mars and Jupiter in our own solar system. and with a mass greater than that of Jupiter.

This discovery demonstrates that modern instruments are capable of directly detecting exoplanets at orbital scales similar to those of our solar system.

Furthermore, since the planet is at the deuterium burning limit, commonly accepted at around 13 Jupiter masses, it could help scientists clarify how to discriminate between objects that may be a brown dwarf or an extrasolar planet.

Professor Hinkley added it’s a statement: “This discovery is also very significant because it shows that we can now directly characterize the atmospheres of these exoplanets where we know from previous studies that they most commonly reside, at about two to four times our Earth/Sun distance.”

The research was accepted for publication by the journal Astronomy & Astrophysics.