Study Refines M87 Black Hole Mass Estimate
New research using JWST and Keck data puts the supermassive black hole at about 5.38 billion solar masses, lower than earlier estimates.
Updated on Nov. 9, 2026 in Physics
A study led by Emily Lippe of the University of California, Riverside, refines the mass estimate of the supermassive black hole at the center of galaxy M87 to approximately 5.38 billion solar masses. The figure is lower than the roughly 6.5 billion solar masses derived from the 2019 Event Horizon Telescope image of the black hole's shadow, though the two estimates are consistent within their error bars.
Why it matters
Black hole mass is a fundamental variable in modeling the accretion disk around the object, which is needed to interpret properties such as spin and turbulence in the telescope image. Reducing the overall uncertainty by a factor of two to three sharpens the physical models scientists use to understand these objects.
The estimate rests on roughly 5,000 stellar motion measurements across 618 regions of M87, with stellar velocity dispersion near the galactic center reaching about 500 kilometers per second. The team's specialized algorithm removed periodic distortions from JWST spectra, but the final mass still sits between the two competing estimates.
The players
Emily Lippe
Lippe is the lead researcher on the study refining the mass of the M87 black hole and is affiliated with the University of California, Riverside.
Event Horizon Telescope
The Event Horizon Telescope is a global network of radio telescopes that produced the 2019 image of the shadow of the M87 supermassive black hole.
The details
The new method measures the velocities of stars orbiting near the galactic center to infer the mass of the unseen black hole. The team combined data from the James Webb Space Telescope and the Keck Observatory, applying a data-cleaning algorithm to remove periodic distortions from the JWST spectra.
Timeline
2019: The Event Horizon Telescope released the first image of the M87 black hole's shadow, yielding the initial mass estimate of roughly 6.5 billion solar masses.
The Big Picture
This refinement updates the mass figure first derived from the 2019 Event Horizon Telescope image of M87's shadow, lowering the estimate while keeping it within the original error range. It shows how combining independent stellar-motion measurements with imaging data can tighten the physical parameters that underpin black hole models.
Better black hole mass measurements help astronomers calibrate the models used to interpret future telescope images and gravitational-wave observations. The practical payoff is more reliable inferences about how these extreme objects grow and behave over time.
The takeaway
Combining data from multiple observatories can sharpen estimates that a single instrument cannot fully constrain. Readers following black hole science should expect mass and spin figures to keep narrowing as these methods mature.
Further reading
For the broader theory behind these measurements, explore Physics coverage on Wisevoter.
