In a scientific first, according to Yale News, astronomers at Yale and Harvard have taken the pulse of distant galaxy called M87, and measured the effects of older red stars on the light of their surroundings. Astronomers have observed many of these stars pulsating in our galaxy.
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“We tend to think of the stars in the sky as unchanging and constant”, he told redOrbit via email. Earth’s Milky Way galaxy has many such starts that are now in this phase.
The researchers used a unique sequence of images of the galaxy M87, in the constellation Virgo, captured by the Hubble Space Telescope over the course of 3 months in the year 2006. The heart-pounding study analyzed how light in nearby galaxy is affected by the stellar pulse.
Astronomers have caught a giant elliptical galaxy “shimmering” as its stars pulsate. If the pulsating stars in M87 have solar systems like our own, we are seeing them at the time when their inner planets have been destroyed – a somewhat unsettling thought! Their brightness sees massive swings as it increases and decreases every few hundred years. By looking at the strength and speed of the galaxy’s pulses, astronomers can determine a galaxy’s age.
Just a like human being or any other living being for that matter, a star is born, it lives out its life, out there, on the cold verges of space and then, at the peak of its life, it begins to grow more luminous and graceful than ever. The heartbeat effect is caused by the pulsating light of old red stars, and this is the first time such an effect has been measured. Conflicting to the belief, galaxies are said to be unsteady beacons, but they are sparkling due to the presence of giant, pulsating constituent stars. It approximately takes a timescale of 270 days to change its brightness.
“We realized that these stars are so bright and their pulsations so strong that they are hard to hide”, Charlie Conroy, lead author of the study and an assistant professor at Harvard, said.
In addition to underlining the potential of Hubble data as source of new discoveries, researchers say the measurements offer a new way of determining the age of such distant systems. The team finds that M87 is about 10 billion years old, a number that agrees with previous estimates using different techniques.
With age, the brightness is expected to dim. Still, the pulsations will continue for a long while more, scientists are convinced.
“Our models suggest that the pulsations will be stronger in younger galaxies, and that’s something we’d love to test”, said co-author Jieun Choi, a Harvard graduate student. The findings of the research were made available in the November 16 online edition of the journal Nature.
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“Amazingly, one in four pixels in the image changes with time”, Prof. van Dokkum said.
