From ICRAR: “Star clusters discovery could upset the astronomical applecart”

ICRAR Logo
International Centre for Radio Astronomy Research

March 7, 2017
Dr Bi-Qing For (ICRAR-UWA)
biqing.for@icrar.org
+61 8 6488 7729

Dr Kenji Bekki (ICRAR-UWA)
kenji.bekki@icrar.org
+61 8 6488 7730

Pete Wheeler—Media Contact, ICRAR
pete.wheeler@icrar.org
+61 423 982 018

1
This image from NASA’s Spitzer Space Telescope features the Large Magellanic Cloud, a satellite galaxy to our own Milky Way galaxy. Overlaying the image are circles showing the locations of 15 star clusters where multiple generations of stars have been discovered. Credit: Karl Gordon and Margaret Meixner – Space Telescope Science Institute/AURA/NASA. Compilation by Bi-Qing For and Kenji Bekki (ICRAR/UWA).

The discovery of young stars in old star clusters could send scientists back to the drawing board for one of the Universe’s most common objects.

Dr Bi-Qing For, from the International Centre for Radio Astronomy Research in Perth, said our understanding of how stars evolve is a cornerstone of astronomical science.

“There are a billion trillion stars in the Universe and we’ve been observing and classifying those we can see for more than a century,” she said.

“Our models of stellar evolution are based on the assumption that stars within star clusters formed from the same material at roughly the same time.”

A star cluster is a group of stars that share a common origin and are held together by gravity for some length of time.

Because star clusters are assumed to contain stars of similar age and composition researchers have used them as an “astronomical laboratory” to understand how mass affects the evolution of stars.

“If this assumption turns out to be incorrect, as our findings suggest, then these important models will need to be revisited and revised,” Dr For said.

The discovery, published today in the Monthly Notices of the Royal Astronomical Society, involves a study of star clusters located in the Large Magellanic Cloud, a neighbouring galaxy to the Milky Way.

By cross-matching the locations of several thousand young stars with the locations of stellar clusters, the researchers found 15 stellar candidates that were much younger than other stars within the same cluster.

“The formation of these younger stars could have been fuelled by gas entering the clusters from interstellar space,” said co-author Dr Kenji Bekki, also from the International Centre for Radio Astronomy Research.

“But we eliminated this possibility using observations made by radio telescopes to show that there was no correlation between interstellar hydrogen gas and the location of the clusters we were studying.

“We believe the younger stars have actually been created out of the matter ejected from older stars as they die, which would mean we have discovered multiple generations of stars belonging to the same cluster.”

Dr Bekki said the stars were currently too faint to see using optical telescopes because of the dust that surrounds them.

“They have been observed using infrared wavelengths by orbiting space telescopes Spitzer and Herschel, operated by NASA and the European Space Agency,” he said.

“An envelope of gas and dust surrounds these young stars but as they become more massive and this shroud blows away, they will become visible at optical wavelengths for powerful instruments like the Hubble Space Telescope.”

“If we point Hubble at the clusters we’ve been studying, we should be able to see both young and old stars and confirm once and for all that star clusters can contain several generations of stars.”

See the full article here .

Please help promote STEM in your local schools.
STEM Icon

Stem Education Coalition

ICRAR is an equal joint venture between Curtin University and The University of Western Australia with funding support from the State Government of Western Australia. The Centre’s headquarters are located at UWA, with research nodes at both UWA and the Curtin Institute for Radio Astronomy (CIRA).
ICRAR has strong support from the government of Australia and is working closely with industry and the astronomy community, including CSIRO and the Australian Telescope National Facility, iVEC, and the international SKA Project Office (SPO), based in the UK.

ICRAR is:

Playing a key role in the international Square Kilometre Array (SKA) project, the world’s biggest ground-based telescope array.

SKA Square Kilometer Array
Attracting some of the world’s leading researchers in radio astronomy, who will also contribute to national and international scientific and technical programs for SKA and ASKAP.
Creating a collaborative environment for scientists and engineers to engage and work with industry to produce studies, prototypes and systems linked to the overall scientific success of the SKA, MWA and ASKAP.

SKA Murchison Widefield Array
A Small part of the Murchison Widefield Array

Enhancing Australia’s position in the international SKA program by contributing to the development process for the SKA in scientific, technological and operational areas.
Promoting scientific, technical, commercial and educational opportunities through public outreach, educational material, training students and collaborative developments with national and international educational organisations.
Establishing and maintaining a pool of emerging and top-level scientists and technologists in the disciplines related to radio astronomy through appointments and training.
Making world-class contributions to SKA science, with emphasis on the signature science themes associated with surveys for neutral hydrogen and variable (transient) radio sources.
Making world-class contributions to SKA capability with respect to developments in the areas of Data Intensive Science and support for the Murchison Radio-astronomy Observatory.

Advertisements