Tuesday, June 28, 2016

Listen Like an Astroseismologist: 13 Billion Year Old Music, The Resonant Songs of the Earliest Stars

Astrophysicists from the University of Birmingham have captured the sounds of some of the oldest stars in our galaxy, the Milky Way, according to research published this month in the journal Monthly Notices of the Royal Astronomical Society


The research team, from the University of Birmingham's School of Physics and Astronomy, has reported the detection of resonant acoustic oscillations of stars in 'M4', one of the oldest known clusters of stars in the Galaxy, some 13 billion years old.

An image of the globular star cluster M4, made with the MPG/ESO 2.2-m telescope at the La Silla Observatory in Chile. The yellow circles mark the positions of the stars observed in the new study. Click the image for an animation and audio from each star.
 Credit: ESO / University of Birmingham

Using data from the NASA Kepler/K2 mission, the team has studied the resonant oscillations of stars using a technique called asteroseismology. These oscillations lead to miniscule changes or pulses in brightness, and are caused by sound trapped inside the stars. By measuring the tones in this 'stellar music', it is possible to determine the mass and age of individual stars. (You can listen to the sound of each star here.)

This discovery opens the door to using asteroseismology to study the very early history of our Galaxy.

Dr Andrea Miglio, from the University of Birmingham's School of Physics and Astronomy, who led the study, said: 'We were thrilled to be able to listen to some of the stellar relics of the early universe. The stars we have studied really are living fossils from the time of the formation of our Galaxy, and we now hope be able to unlock the secrets of how spiral galaxies, like our own, formed and evolved.'

Dr Guy Davies, from the University of Birmingham's School of Physics and Astronomy, and co-author on the study, said: 'The age scale of stars has so far been restricted to relatively young stars, limiting our ability to probe the early history of our Galaxy. In this research we have been able to prove that asteroseismology can give precise and accurate ages for the oldest stars in the Galaxy '

Professor Bill Chaplin, from the University of Birmingham's School of Physics and Astronomy and leader of the international collaboration on asteroseismology, said: 'Just as archaeologists can reveal the past by excavating the earth, so we can use sound inside the stars to perform Galactic archaeology.'

Contacts and sources:
Luke Harrison
Prof Andrea Miglio
University of Birmingham

Citation:  The work appears in "Detection of solar-like oscillations in relics of the Milky Way: asteroseismology of K giants in M4 using data from the NASA K2 mission", A. Miglio, W. J. Chaplin, K. Brogaard, M. N. Lund, B. Mosser, G. R. Davies, R. Handberg, A. P. Milone, A. F. Marino, D. Bossini, Y. P. Elsworth, F. Grundahl, T. Arentoft, L. R. Bedin, T. L. Campante, J. Jessen-Hansen, C. D. Jones, J. S. Kuszlewicz, L. Malavolta, V. Nascimbeni and E. L. Sandquist, Monthly Notices of the Royal Astronomical Society, in press.

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