30/08/2026

theSunday Special VI ON SUNDAY AUG 30, 2026

Fastest star orbits Milky Way black hole

S CIENTISTS have detected the fastest-known star, a stellar speedster that is zooming around a supermassive black hole residing at the centre of our galaxy, and might hold the key to measuring the spin of this celestial beast for the first time. The star, about 50% more massive and five times brighter than our sun, travels at speeds up to about 90 million km per hour as it orbits the Milky Way’s central black hole – named Sagittarius A*, or Sgr A*. That is more than 8% the speed of light. No other star in our galaxy or elsewhere has ever been clocked at that speed. The star, named S301, is traveling in a highly elliptical path around Sgr A*, taking about 8.7 years to complete an orbit. Its closest approach to the black hole is about 11.5 times Earth’s orbital distance from the sun, a metric called an astronomical unit. That means the star’s nearest pass is somewhat more than the planet Saturn’s orbital distance from the sun. But at its farthest, S301 is about 1,360 astronomical units from Sgr A*. Black holes are extraordinarily dense objects with gravity so strong that not even light can escape. Sgr A* possesses about four million times the sun’s mass and is located about 26,000 light-years from Earth. A light-year is the distance light travels in a year, 9.5 trillion km. While Sgr A* is presently in a quiescent state, its gravitational pull is considerable – meaning it could gulp down stars or other material straying too close. But the researchers said S301 should remain safe from the black hole’s wrath. “Its orbit will not decay anytime soon. The orientation of the orbit will change, but it is not in danger of being swallowed,” said astrophysicist Stefan Gillessen of the Max Planck Institute for Extraterrestrial Physics in Germany, one of the leaders of the research published recently in the journal Nature . No other star is known to orbit as close to Sgr A* as this one. So, how did S301 end up with this crazy orbit? Gillessen said it appears that S301 originally was part of a two-star system called a binary, gravitationally bound to a stellar partner. But the two stars at some point ventured too close to the black hole while travelling through space and the subsequent three-way gravitational interaction wreaked havoc. The object looks like a star the size of our solar system, but produces 100 billion times more energy than any star – a mighty blast of power closer to what is produced by a black hole. The black hole star, which dates from 660 million years after the Big Bang, was spotted by a US-led team of astronomers using the James Webb Space Telescope (JWST), according to a study published in the journal Nature . Since history’s most powerful telescope went online in 2022, it has been spotting many extremely bright cosmic objects dubbed “little red dots” in the early universe that have baffled scientists. “What exactly these objects are has been one of the most debated topics of the JWST era,” lead study author Rohan Naidu of Hawaii University said in a statement. The team had been trying to find clues for a different mystery: Why JWST keeps finding bright galaxies in the universe’s infancy, when it was thought to have been too early for them to have become so huge. But while looking through the images, they spotted a little red dot.

S301 could be key to measuring spin of supermassive celestial beast at centre of galaxy “One star shoots out from the centre of the Milky Way travelling at high speed and even leaving the galaxy. The other star is stuck forever on an orbit close to the black hole. That is S301,” Gillessen said. The researchers observed S301 using the European Southern Observatory Chile-based Very Large Telescope Interferometer. The continuing influence that Sgr A* exerts on S301 during its orbit may enable scientists to better understand the black hole, including possibly measuring its spin. “Currently, there is very little that we know about the rotation of Sgr A*,” said study co-author Felix Mang, a doctoral student at the Max Planck Institute for Extraterrestrial Physics. Black holes are believed to rotate, so much so that they twist the very fabric of space and time around them. But confirming this spin is difficult because black holes do not emit or reflect light, rendering them invisible. “We only can see their rotation by seeing the effect on the space around them,” Gillessen said. The researchers said the motion of S301 remains sensitive to Sgr A*. “The star during its orbit comes so close to Sgr A* that it actually will feel the spin of Sgr A*. “It is not a wobble – like in back and forth – but rather the star gets pushed onto a slightly different orbit each time it passes the black hole. That means that by observing that change in orbit for another decade, we should be able to directly determine the spin of the black hole. Such a measurement is unheard of, so far,” Gillessen said. – Reuters

Sgr A* is the supermassive black hole at the centre of our galaxy. – ESO HANDOUT PIC VIA REUTERS

Astronomers find new space object, possible solution to red dot mystery ASTRONOMERS announced recently they had discovered a new type of astronomical object called a “black hole star”, potentially solving a mystery involving strange red dots spotted in the early universe. from the Massachusetts Institute of Technology. However, when the team sifted through their data, they found that at certain wavelengths, the object’s light simply disappeared.

To their surprise, this suggested that it is not dust making this object appear red – it is hydrogen gas. This explained the object’s colour, but not how it could be pumping out so much energy. “You can’t be powering this by nuclear fusion, which is the energy source that sits at the heart of all the stars,” Naidu explained. Using modelling simulations, they determined the most likely scenario was that the object is powered by a central black hole surrounded by a cocoon of gas that makes it resemble a star. The team named the object MoM-BH*-1. The BH and asterix is for black hole star – and the number one suggests they believe there are more out there. “Every little red dot is consistent with being a black hole star. “What is special about MoM-BH*-1 is the black hole star is essentially completely outshining its surrounding host galaxy, such that we’re seeing pure black hole star light,” Naidu said. – AFP

The JWST, which spotted the new astronomical object called a ‘black hole star’, floats through space. – NASA HANDOUT VIA AFP ‘Pure black hole star light’

from Canada recently made the sky in Boston look bright red, astronomical objects can also appear redder than their intrinsic colour when you see them through a veil of dust,” said Robert Simcoe, a study co-author

“When we see something very red in the universe, we often assume that it is surrounded by dust, such as soot or ash. “The same way that the wildfire smoke