LHA 120-N55 in the constellation of Dorado
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Zooming in on the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud
Close-up view of the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud
In this image from ESO’s Very Large
Telescope (VLT), light from blazing blue stars energises the gas left
over from the stars’ recent formation. The result is a strikingly
colourful emission nebula, called LHA 120-N55, in which the stars are
adorned with a mantle of glowing gas. Astronomers study these beautiful
displays to learn about the conditions in places where new stars
develop.
LHA 120-N55, or N55 as it is usually known, is a glowing gas cloud in the Large Magellanic Cloud
(LMC), a satellite galaxy of the Milky Way located about 163 000
light-years away. N55 is situated inside a supergiant shell, or
superbubble called LMC 4. Superbubbles,
often hundreds of light-years across, are formed when the fierce winds
from newly formed stars and shockwaves from supernova explosions work in
tandem to blow away most of the gas and dust that originally surrounded
them and create huge bubble-shaped cavities.
The material that became N55, however, managed to survive as a small
remnant pocket of gas and dust. It is now a standalone nebula inside the
superbubble and a grouping of brilliant blue and white stars — known as
LH 72 — also managed to form hundreds of millions of years after the
events that originally blew up the superbubble. The LH 72 stars are only
a few million years old, so they did not play a role in emptying the
space around N55. The stars instead represent a second round of stellar
birth in the region.
The recent rise of a new population of stars also explains the
evocative colours surrounding the stars in this image. The intense light
from the powerful, blue–white stars is stripping nearby hydrogen atoms
in N55 of their electrons, causing the gas to glow in a characteristic
pinkish colour in visible light. Astronomers recognise this telltale
signature of glowing hydrogen gas throughout galaxies as a hallmark of
fresh star birth.
While things seem quiet in the star-forming region of N55 for now,
major changes lie ahead. Several million years hence, some of the
massive and brilliant stars in the LH 72 association will themselves go
supernova, scattering N55’s contents. In effect, a bubble will be blown
within a superbubble, and the cycle of starry ends and beginnings will
carry on in this close neighbour of our home galaxy.
This new image was acquired using the FOcal Reducer and low dispersion Spectrograph (FORS2) instrument attached to ESO's VLT. It was taken as part of the ESO Cosmic Gems programme,
an outreach initiative to produce images of interesting, intriguing or
visually attractive objects using ESO telescopes for the purposes of
education and public outreach. The programme makes use of telescope time
that cannot be used for science observations. All data collected may
also be suitable for scientific purposes, and are made available to
astronomers through ESO’s science archive.
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Contacts
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Source: ESO
