Harvard-Smithsonian Center for Astrophysics | 2015 Nov 16
[img3="The monstrous elliptical galaxy M87, located 53 million light-years from Earth isIn many ways stars are like living beings. They're born; they live; they die. And they even have a heartbeat. Using a novel technique, astronomers have detected thousands of stellar "pulses" in the galaxy Messier 87 (M87). Their measurements offer a new way of determining a galaxy's age.
the dominant galaxy at the center of the neighboring Virgo cluster of galaxies.
Astronomers have measured the "heartbeats" of stars within M87 and used that
data to determine the galaxy's age in a new way. This photograph was taken with
the Hubble Space Telescope's Advanced Camera for Surveys instrument.
(Credit: NASA, ESA, and the Hubble Heritage Team)"]https://www.cfa.harvard.edu/sites/www.c ... 1/base.jpg[/img3][hr][/hr]
We tend to think of stars as stable and unchanging. However, late in life stars like the Sun undergo a significant transformation. They become very bright and swell up to an enormous size, swallowing any planets that are within Earth's distance from the Sun. Near the end of their lifetime they begin to pulsate, increasing and decreasing their brightness by a large amount every few hundred days. In our own Milky Way galaxy many stars are known to be in this stage of life.
No one had considered the effects of these stars on the light coming from more distant galaxies. In distant galaxies the light of each pulsating star is mixed in with the light of many more stars that are not varying in brightness.
"We realized that these stars are so bright and their pulsations so strong, that they are difficult to hide," said Charlie Conroy, an assistant professor at Harvard University and astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA), who led the research. "We decided to see if the pulsations of these stars could be detected even if we couldn’t separate their light from the sea of unchanging stars that are their neighbors."
The astronomers studied the elliptical galaxy M87, located 53 million light-years from Earth in the constellation Virgo. They examined a unique series of images taken with the Hubble Space Telescope over the course of three months in 2006. They quickly found what they were looking for. ...
We’ve got the beat: Astronomers discover a distant galaxy with a pulse
Yale University | 2015 Nov 16
Ubiquitous Time Variability of Integrated Stellar Populations - Charlie Conroy, Pieter van Dokkum, Jieun Choi
- Nature (online 16 Nov 2015) DOI: 10.1038/nature15731
arXiv.org > astro-ph > arXiv:1511.04086 > 12 Nov 2015