The Rosy Glow of a Cosmic Seagull
The Seagull Nebula on the borders of the constellations of Monoceros and Canis Major
Wide-field view of the entire Seagull Nebula (IC 2177)
Videos
ESOcast 205 Light: The Rosy Glow of a Cosmic Seagull
Panning across the Cosmic Seagull
Zooming into the Cosmic Seagull
ESO’s VST captures a celestial gull in flight
Colourful and wispy, this intriguing
collection of objects is known as the Seagull Nebula, named for its
resemblance to a gull in flight. Made up of dust, hydrogen, helium and
traces of heavier elements, this region is the hot and energetic
birthplace of new stars. The remarkable detail captured here by ESO’s
VLT Survey Telescope (VST) reveals the individual astronomical objects
that make up the celestial bird, as well as the finer features within
them. The VST is one of the largest survey telescopes in the world
observing the sky in visible light.
The main components of the Seagull are three large clouds
of gas, the most distinctive being Sharpless 2-296, which forms the
“wings”. Spanning about 100 light-years from one wingtip to the other,
Sh2-296 displays glowing material and dark dust lanes weaving amid
bright stars. It is a beautiful example of an emission nebula, in this case an HII region, indicating active formation of new stars, which can be seen peppering this image.
It is the radiation emanating from these young stars that
gives the clouds their fantastical colours and makes them so
eye-catching, by ionising the surrounding gas and causing it to glow.
This radiation is also the main factor that determines the clouds’
shapes, by exerting pressure on the surrounding material and sculpting
it into the whimsical morphologies we see. Since each nebula has a
unique distribution of stars and may, like this one, be a composite of
multiple clouds, they come in a variety of shapes, firing astronomers’
imaginations and evoking comparisons to animals or familiar objects.
This diversity of shapes is exemplified by the contrast
between Sh2-296 and Sh2-292. The latter, seen here just below the
“wings”, is a more compact cloud that forms the seagull’s “head”. Its
most prominent feature is a huge, extremely luminous star called HD
53367 that is 20 times more massive than the Sun, and which we see as
the seagull’s piercing “eye”. Sh2-292 is both an emission nebula and a
reflection nebula; much of its light is emitted by ionised gas
surrounding its nascent stars, but a significant amount is also
reflected from stars outside it.
The dark swathes that interrupt the clouds’ homogeneity and give them texture are dust lanes
– paths of much denser material that hide some of the luminous gas
behind them. Nebulae like this one have densities of a few hundred atoms
per cubic centimetre, much less than the best artificial vacuums on
Earth. Nonetheless, nebulae are still much denser than the gas outside
them, which has an average density of about 1 atom per cubic centimetre.
The Seagull lies along the border between the constellations of Canis Major (The Great Dog) and Monoceros (The Unicorn), at a distance of about 3700 light-years in one arm of the Milky Way. Spiral galaxies can contain thousands of these clouds, almost all of which are concentrated along their whirling arms.
Several smaller clouds are also counted as part of the Seagull Nebula,
including Sh2-297, which is a small, knotty addition to the tip of the
gull’s upper “wing”, Sh2-292 and Sh2-295. These objects are all included
in the Sharpless Catalogue, a list of over 300 clouds of glowing gas compiled by American astronomer Stewart Sharpless.
This image was taken using the VLT Survey Telescope
(VST), one of the largest survey telescopes in the world observing the
sky in visible light. The VST is designed to photograph large areas of
the sky quickly and deeply.
Can you spot the seagull in this photo? We challenge our
readers to let their imagination run free and outline the bird in our
photo as they see it. Share your photos with the outline of the bird
using the hashtag #SpotTheSeagull.
More Information
ESO is the foremost intergovernmental astronomy organisation in Europe
and the world’s most productive ground-based astronomical observatory by
far. It has 16 Member States: Austria, Belgium, the Czech Republic,
Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands,
Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom,
along with the host state of Chile and with Australia as a Strategic
Partner. ESO carries out an ambitious programme focused on the design,
construction and operation of powerful ground-based observing facilities
enabling astronomers to make important scientific discoveries. ESO also
plays a leading role in promoting and organising cooperation in
astronomical research. ESO operates three unique world-class observing
sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO
operates the Very Large Telescope and its world-leading Very Large
Telescope Interferometer as well as two survey telescopes, VISTA working
in the infrared and the visible-light VLT Survey Telescope. Also at
Paranal ESO will host and operate the Cherenkov Telescope Array South,
the world’s largest and most sensitive gamma-ray observatory. ESO is
also a major partner in two facilities on Chajnantor, APEX and ALMA, the
largestastronomical project in existence. And on Cerro Armazones,
close to Paranal, ESO is building the 39-metre Extremely Large
Telescope, the ELT, which will become “the world’s biggest eye on the
sky”.
Contact:
Mariya Lyubenova
ESO Head of Media Relations Team
Garching bei München, Germany
Tel: +49 89 3200 6188
Email: pio@eso.org
ESO Head of Media Relations Team
Garching bei München, Germany
Tel: +49 89 3200 6188
Email: pio@eso.org
Source: ESO/News
