October 30, 2024
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The fastest known planetary system to have been powered by our Galaxy’s Supermassive Black Hole
This incredibly fast star is crossing the Milky Way with a planet in tow
Hubble Space Telescope view of the dense region of stars near the center of the Milky Way, known as the galactic bulge.
It orbits our solar system milky way galaxy Every 225 million years, approximately, at a speed of 230 kilometers per second (a tremendous speed that we do not feel because everything is moving at the same constant speed). But a new study suggests that we’re a cosmic slow motion compared to a system in our own galaxy that has somehow rocketed to 541 kilometers per second, the fastest known planetary system.
“This speed was very high and shocking,” says University of Maryland astrophysicist Sean Terry, lead author of the study. preprint server arXiv.org and present Astrophysical magazine. “It opens up a regime of questions about the survival of these types of systems.”
This galactic speed demon appears to contain a red dwarf star smaller and dimmer than our sun. It is 25,000 light-years from Earth and 1,000 light-years from the center of our galaxy. Astronomers he found the star and a suspected companion planet after a microlensing event named MOA-2011-BLG-262 in 2011, when the system passed in front of a background star and distorted the latter’s light.
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Terry and his colleagues observed the system again in 2021 from the WM Keck Observatory in Hawaii. Its known planet is found to be a gas giant about 29 times the mass of Earth, orbiting its star at a distance between Venus and Earth’s orbit around the sun. (The system may also contain unseen planets.) The researchers also mapped the system’s position in the 2021 data relative to where it was about a decade ago, revealing just how fast it traveled.
This speed suggests that the star of the system may be a hypervelocity staran example of a rare class of stellar objects accelerated by past encounters with other stars, or even a gravitational slingshot from the supermassive black hole at the center of our galaxy. These objects travel faster than 500 kilometers per second, and the fastest known one travels at more than 2,000 km per second. “It’s this really exotic subset of stars,” Terry says, noting that the system’s velocity doubled after its dramatic encounter. No hypervelocity stars have been found with planets, he added.
Jessie Christiansen of NASA’s Exoplanet Science Institute, who was not involved in the research, says the system offers clues about the worlds in the star-dense region at the center of our galaxy. We don’t know if being in that galactic bulge “affects the types of planetary systems that form,” he says.
Although the planet in the fast system is far from the zone around a known red dwarf, where liquid water (and therefore life as we know it) can survive on the surface, its existence suggests that planets can survive the “rather chaotic interaction” that occurs when stars are present. it has accelerated to incredible speeds, says Terry. “This could open up a new study of the origin and evolution of planets around very high-velocity stars,” he added.
