All articles tagged with #sagittarius a
Astronomers have identified S301, a faint main‑sequence star on an 8.7‑year, highly eccentric orbit around the Milky Way’s supermassive black hole Sagittarius A*, reaching speeds up to 25,000 km/s (about 0.08c) at pericenter. This motion probes relativistic effects and could reveal the spin of Sgr A*, with S301 likely a captured binary via the Hills mechanism.
Astronomers have identified S301, a star orbiting extremely close to the Milky Way's central black hole, Sagittarius A*, reaching about 15,500 miles per second (roughly 55.8 million mph)—the fastest speed ever observed and the closest approach to the black hole to date. Its extreme proximity allows direct tests of relativistic effects, such as frame-dragging (Lense-Thirring), with upcoming measurements from facilities like the Gravity instrument on the VLT and MICADO on the ELT over the next decade.
Using ESO’s GRAVITY instrument at the VLT, astronomers have found S301, a faint star at the Milky Way’s center on the closest, fastest orbit around Sagittarius A*. With an 8.7-year period, it swings within about 12 astronomical units of the black hole at pericenter, racing at roughly 55 million mph (about 0.008c). Tracked across eight years in 19 positions, the star shows strong general-relativistic effects such as Schwarzschild precession, and within a decade could enable a direct measurement of the black hole’s spin. S301 likely originated from a disrupted binary, and its discovery boosts tests of gravity in extreme fields while hinting at many more such stars detectable with GRAVITY+.
Astronomers have identified S301, the Milky Way’s fastest star, racing around the galaxy’s supermassive black hole Sagittarius A* at about 15,500 miles per second (over 8% of light). Its tight 8.7-year orbit, roughly 12 AU from the black hole, offers a novel way to probe Sagittarius A*’s spin and test general relativity via frame dragging, using the GRAVITY instrument on ESO’s Very Large Telescope Interferometer. The discovery, reported in Nature, could allow direct measurements of the black hole’s spin within a decade as researchers continue to monitor two full orbits; S301 may have been captured from a binary system.
Astronomers using the GRAVITY+ instrument have tracked star S301 in an ultra-tight, 8.7-year orbit around the Milky Way’s supermassive black hole Sgr A*, reaching peak speeds over 25,000 km/s (about 15,500 miles/s, ~8% of light speed). The extreme motion near pericenter exposes frame-dragging and spacetime curvature, offering a path to measure Sgr A*’s spin and test the no-hair theorem of black holes, with continued observations through 2031 and future ELT instruments like MICADO.
Astronomers have found S301, the Milky Way’s fastest star, zooming around the central black hole Sagittarius A* at about 25,000 km/s on a tight 8.7-year orbit, coming within roughly 12 AU of the hole. Its extreme proximity could enable a direct measurement of the black hole’s spin and a stringent test of Einstein’s general relativity, using the ESO Very Large Telescope Interferometer to track the orbit back to 2017 and observe the 2031 pericentre passage; spin measurements could come within a decade.
JWST’s mid-infrared study of the inner parsec around the Milky Way’s Sagittarius A* detects water and dust being expelled by the dying AGB star IRS 3, showing that star-produced material can endure in the harsh galactic-center environment. Models suggest IRS 3 formed farther out and migrated inward, continuing to enrich its surroundings with a bright, long-lived stellar wind; the work demonstrates that molecular material can survive near a supermassive black hole and was published in Astronomy & Astrophysics.
For nearly 30 years, astronomers tracked the star S2 as it orbits the Milky Way’s center around Sagittarius A*, a supermassive black hole about 4 million solar masses. At its closest approach it reaches ~7,650 km/s (~0.025c), enabling precise tests of general relativity in strong gravity via relativistic effects like gravitational redshift, transverse Doppler shift, and Schwarzschild precession. The findings—made with ESO's GRAVITY and Keck, by Genzel and Ghez’s teams—helped secure the Nobel Prize in Physics 2020 and complement the Event Horizon Telescope’s 2022 image of the black hole’s shadow.
Astronomers are rethinking the Milky Way’s centre: the long-held view that a supermassive black hole (Sagittarius A*) sits at the heart may be challenged by a fermionic dark matter core that could explain the observed stellar motions and even mimic the black hole’s shadow. Distinguishing the scenarios hinges on precise orbital precession measurements, which future upgrades like GRAVITY+ and the Extremely Large Telescope (and next-gen EHT observations) could enable. If verified, the idea would reshape galactic dynamics and dark matter physics, forcing a rethink of how galaxies host and regulate their centres.
Astronomers using ALMA and Chandra detected a cone-shaped cavity around Sagittarius A*, signaling a hot wind from the Milky Way’s central black hole that has cleared nearby gas; the outflow is estimated to have been active for at least 20,000 years, offering new insight into how Sgr A* influences its environment even in a relatively quiet state and into black hole feedback in galaxies.
Astronomers used reverberation (echo) mapping to probe gas around supermassive black holes in 14 galaxies, finding in five cases that the enclosed mass increases with distance from the SMBH beyond what visible matter can explain. The results hint at dark matter clustering around SMBHs like Sagittarius A* and M87, offering a new method to study dark matter environments, though the findings are preliminary and not conclusive.
Astronomers using ALMA radio maps and NASA’s Chandra X-ray data detected a 3-light-year cone-shaped cavity around Sagittarius A*, the Milky Way’s supermassive black hole, indicating a previously unseen wind. The finding helps explain why our galaxy’s center appeared windless and provides a new observable for understanding how black holes influence their host galaxies.
NASA’s Chandra X-ray Observatory, with help from XMM-Newton, detected a bright X-ray blob near the Milky Way’s center—likely the wreckage of a supernova that exploded about 1,700 years ago and is the closest such debris to Sagittarius A*. The debris lies in a bubble of ionized gas dubbed Sagittarius C and is seen moving at roughly 2 million mph. While an SN origin is favored, some uncertainty remains whether the emission could be from gas heated by nearby massive stars. The study, published in The Astrophysical Journal, highlights how such debris contributes to chemical enrichment and the birth of future stars and planets.
The Event Horizon Telescope released the first image of the Milky Way’s central black hole, Sagittarius A*, in 2022. The 4-million-solar-mass object lies about 27,000 light-years away. Eight linked radio observatories formed an Earth-sized telescope, and the ring around the shadow matches General Relativity despite the object’s minute-scale variability; researchers now plan time-resolved movies to study gravity in action.
Astronomers using ALMA and Chandra observations have captured the first clear evidence of a wind blowing from the Milky Way’s central supermassive black hole, Sagittarius A*, carving a cone-shaped cavity in surrounding cold gas and indicating the black hole has been actively shaping its environment for at least 20,000 years while remaining relatively quiet compared with active galaxies.