Astronomers discover how long-lived Peter Pan discs evolve
Date:
June 11, 2020
Source:
Queen Mary University of London
Summary:
New research has revealed how long-lived Peter Pan discs form,
which could provide new insights into how planets arise.
FULL STORY ==========================================================================
New research from scientists at Queen Mary University of London has
revealed how long-lived Peter Pan discs form, which could provide new
insights into how planets arise.
========================================================================== Planet-forming, or protoplanetary, discs are giant discs of gas and
dust found circling young stars. The recently discovered Peter Pan discs received their name as like their fictional counterpart they are thought
to "never grow up," living around 5-10 times longer than other typical protoplanetary discs.
Whilst astronomers have been aware of the existence of Peter Pan discs
since 2016, questions around how and why these discs live so long and
the implications for how planets form, have been left unanswered.
In this study, the scientists used computer simulations to look at a range
of possible starting configurations and ways in which the disc evolves
to reveal the combination of conditions needed to form Peter Pan discs,
which they termed 'Neverland's parameters'. They found these discs only
form in lonely environments, away from other stars, and that they need
to start out much larger than normal discs.
Dr Gavin Coleman, first author of the study and postdoctoral researcher
at Queen Mary, said: "Most stars form in big groups containing around
100,000 stars however it seems that Peter Pan discs can't form in these environments.
They need to be much more isolated from their stellar neighbours as the radiation from other stars would blow these discs away. They also need
to start out massive, so they have more gas to lose and are therefore
able to live for much longer." Until the discovery of long-lived Peter
Pan discs, scientists thought that all discs had a lifetime of a few
million years and faded away by 10 million years, suggesting that the
planets within them must form quickly.
Dr Thomas Haworth, a Dorothy Hodgkin Fellow at Queen Mary, said: "The
existence of these long-lived discs was really surprising, and finding
out why these discs can survive longer than expected could be critical
for helping us understand more about disc evolution and planet formation
in general. A particularly interesting point is that Peter Pan discs have
so far only been found around low mass stars, and these low mass stars are generally being found to host lots of planets. The large disc masses that
we need to end up with Peter Pan discs could be an important ingredient
that allows these planets to exist." Due to the specific environment
needed for the formation of these discs it is expected that they are
very rare. So far, seven Peter Pan discs have been discovered as the
result of a citizen science collaboration between NASA and Zooniverse,
known as the Disk Detective project.
Dr Coleman, said: "It's great that the findings of a citizen science
project are now fuelling novel scientific research into these unique
discs, and could even help us to better understand planet formation,
one of the key problems in astrophysics."
========================================================================== Story Source: Materials provided by Queen_Mary_University_of_London. Note: Content may be edited for style and length.
========================================================================== Journal Reference:
1. Thomas J Haworth, Gavin A L Coleman. Peter Pan discs: finding
Neverland's
parameters. Monthly Notices of the Royal Astronomical Society:
Letters, 2020; 496 (1): L111 DOI: 10.1093/mnrasl/slaa098 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2020/06/200611094206.htm
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