Astronomy: A second wave of star formation (N&V)
*IMAGE*
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Astronomy and planetary science
Embargo
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London: Wednesday 27 January 2016 18:00 (GMT)
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New York: Wednesday 27 January 2016 13:00 (EST)
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Tokyo: Thursday 28 January 2016 03:00 (JST)
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Sydney: Thursday 28 January 2016 05:00 (AEDT)
Observations of three massive clusters of ‘young’ stars (1–2 billion years old) in a pair of nearby galaxies are
reported in this week’s Nature. The study finds evidence of star formation that occurred a few hundred million
years after an initial star-forming event, and shows that star clusters may be able to accrete enough gas from
their environment to create new stars.
Stars in clusters are thought to form in a single burst from a common cloud of gas. However, ‘old’ globular
clusters — those with ages greater than 10 billion years — often have populations of younger stars, indicating
that more than one star-forming event may have occurred.
Chengyuan Li and colleagues determined that the clusters they observed, in two dwarf galaxies orbiting the Milky
Way, have populations of stars that are a few hundred million years younger than the main stellar population,
indicating a separate burst of star formation. They find that these clusters could have accreted enough gas to
form new stars if they had orbited in their galaxies’ gaseous disks between their initial formation and the more
recent bursts of star formation. Alternative explanations for the younger population, such as stellar collisions or
accretion of gas from companion stars, are not compatible with their observations.
Article and author details
1. Formation of new stellar populations from gas accreted by massive young star
clusters
Corresponding Author
Chengyuan Li
Peking University, Beijing, China
Email: joshuali@pku.edu.cn, Tel: +86 18168 054025
N&V Author
Antonella Nota
Space Telescope Science Institute and European Space Agency, Baltimore, MD, USA
E-mail: nota@stsci.edu
DOI
10.1038/nature16493
Online paper*
http://nature.com/articles/doi:10.1038/nature16493
* Please link to the article in online versions of your report (the URL will go live after the embargo ends).
Image 1
Caption: A portrait of the massive globular cluster NGC 1783 in the Large Magellanic Cloud taken by the
Hubble Space Telescope. This dense swarm of stars is located about 160,000 light years from Earth
and has the mass of about 170,000 Suns.
Credit: ESA/Hubble & NASA