Beta Crucis is represented within the flags of Australia, Brazil, New Zealand, Papua New Guinea and Samoa.
Beta Crucis. Image credit score: Naskies at en.wikipedia / CC BY-SA 3.0.
Beta Crucis is a triple star system positioned at a distance of 280 light-years from the Earth.
Also generally known as HD 111123, HIC 62434, Becrux and Mimosa, it’s the second-brightest object within the constellation of Crux and the twentieth brightest star within the evening sky.
The main star within the system, beta Crucis A, is a beta Cephei variable star with speedy brightness modifications.
The secondary, beta Crucis B, is a most important sequence star with a stellar class of B2.
And the third companion is a low mass, pre-main sequence star.
To crack the age and mass of beta Crucis A, Dr. Daniel Cotton from the Australian National University and Monterey Institute for Research in Astronomy and his colleagues mixed asteroseismology, the research of a star’s common actions, with polarimetry, the measurement of the orientation of sunshine waves.
“Asteroseismology relies on seismic waves bouncing around the interior of a star and producing measurable changes in its light,” they defined.
“Probing the interiors of heavy stars that will later explode as supernovae has traditionally been difficult.”
In the research, the authors analyzed information from NASA’s WIRE and TESS satellites, high-resolution spectroscopic information from ESO, and polarimetric information from Siding Spring Observatory and Western Sydney University’s Penrith Observatory.
“We wanted to investigate an old idea,” Dr. Cotton stated.
“It was predicted in 1979 that polarimetry had the potential to measure the interiors of massive stars, but it’s not been possible until now.”
“The size of the effect is quite small,” added Professor Jeremy Bailey, an astronomer on the University of New South Wales.
“We needed the world’s best precision of the polarimeter we designed and built.”
The group discovered beta Crucis A to be roughly 14.5 occasions as large because the Sun and round 11 million years previous, making it the heaviest star with an age decided from asteroseismology ever.
“Analyzing the three types of long-term data together allowed us to identify Mimosa’s dominant mode geometries,” stated Professor Derek Buzasi, an astronomer at Florida Gulf Coast University.
“This opened the road to weighing and age-dating the star using seismic methods.”
“This polarimetric study of Mimosa opens a new avenue for asteroseismology of bright massive stars,” added Professor Conny Aerts, an astronomer with the Institute of Astronomy at KU Leuven, Radboud University Nijmegen, and the Max Planck Institute for Astronomy.
“While these stars are the most productive chemical factories of our Galaxy, they are so far the least analyzed asteroseismically, given the degree of difficulty of such studies. The heroic efforts by the Australian polarimetrists are to be admired.”
The group’s paper was revealed within the journal Nature Astronomy.
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D.V. Cotton et al. Polarimetric detection of non-radial oscillation modes within the β Cephei star β Crucis. Nat Astron, revealed on-line December 6, 2021; doi: 10.1038/s41550-021-01531-9