Alex Filippenko and his collaborators are determining the nature of the progenitor stars and the explosion mechanisms of different types of supernovae and gamma-ray bursts. He is also using supernovae as cosmological distance indicators, and he was a member of both teams that discovered (in 1998) the accelerating expansion of the Universe, probably driven by "dark energy" -- a discovery that was honored with the 2011 Nobel Prize in Physics to the teams' leaders. He also works on quantifying the physical properties of quasars and active galaxies, and he searches for black holes in both X-ray binary stars and nearby galactic nuclei. His group has developed the 0.76-meter Katzman Automatic Imaging Telescope (KAIT), which is conducting one of the world's most successful searches for relatively nearby supernovae, having discovered more than 1000 of them. He is a frequent user of Lick Observatory, the 10-meter Keck telescopes, and the Hubble Space Telescope.
Research Expertise and Interest
supernovae, active galaxies, black holes, gamma-ray bursts, expansion of the universe
July 26, 2022
A dense, collapsed star spinning 707 times per second — making it one of the fastest spinning neutron stars in the Milky Way galaxy — has shredded and consumed nearly the entire mass of its stellar companion and, in the process, grown into the heaviest neutron star observed to date. Alex Filippenko, Distinguished Professor of Astronomy at the University of California, Berkeley, explores further.
July 11, 2022
In 2019, astronomers observed the nearest example to date of a star that was shredded, or “spaghettified,” after approaching too close to a massive black hole. That tidal disruption of a sun-like star by a black hole 1 million times more massive than itself took place 215 million light years from Earth. Luckily, this was the first such event bright enough that astronomers from the University of California, Berkeley, could study the optical light from the stellar death, specifically the light’s polarization, to learn more about what happened after the star was torn apart.
June 28, 2021
Astronomers have found convincing evidence that supernovae come in a third flavor, powered by a long-suspected explosive mechanism that may explain a bright supernova humans observed 1,000 ago and that birthed the beautiful Crab Nebula.
November 18, 2018
Astronomers may finally have tracked down the type of star that explodes with a distinctive but unusual signature: They show no evidence of hydrogen and helium, by far the most abundant elements in the universe.