The mass of the first planet without a star was measured

According to Isnanot all planets are lucky enough to live in a space like our solar system, and some are doomed to wander the cosmos alone.

Astronomers have now, for the first time, measured the mass and distance of one of these lonely worlds. This planet has about one-fifth the mass of Jupiter and is a little less than 10,000 light-years away from Earth towards the center of the Milky Way.

This size suggests that it most likely formed as part of a planetary system before being banished by a game of gravitational billiards.

These wandering planets are not directly visible due to their small and dim light. Instead, astronomers usually observe them for their effects on distant light. When they pass between us and a bright background body like a star, the planet’s gravitational influence acts like a lens, briefly magnifying or bending the light.

To determine the mass of a converging object, you usually need to know how far away it is from you, and a planet flying by itself provides few contextual clues, so calculating its distance is difficult, but in this case, astronomers were lucky.

The initial convergence event was observed independently by several ground-based telescopes in Chile, South Africa, and Australia on May 3, 2024. It was also observed by the now-retired Gaia space telescope 6 times in a 16-hour period.

The interesting thing is that “Gaia” was located at a distance of 1.5 million kilometers from the earth at the time of this microconvergence event, and from the telescopes on the ground, they gave it a slightly different sky view.

Starlight reaches each observer at different times, allowing astronomers to estimate the distance to the converging mass, and more generally, its mass, in much the same way our brain perceives distance from the slightly deviated inputs we receive through our eyes.

The team calculated that the planet is about 9,785 light-years from Earth and has a mass of about 22% that of Jupiter.

In a related paper, Gavin Coleman, an astrophysicist at Queen Mary University of London, said the technique could be particularly useful for studying errant planets after the Nancy Grace Roman space telescope launches in 2027.

He added: This finding shows how coordinated observations can overcome the problems of determining the position and mass of a wandering planet and improve the understanding of how these planets formed.

This powerful new telescope will scan large swaths of the sky 1,000 times faster than Hubble, increasing our chances of capturing another gravitational lensing event like this one.

This research was published in Science magazine.

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