The colourful star cluster NGC 3532
The location of the bright star cluster NGC 3532 in the constellation of Carina
Wide-field view of the sky around the bright star cluster NGC 3532
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The MPG/ESO 2.2-metre telescope at ESO’s
La Silla Observatory in Chile has captured a richly colourful view of
the bright star cluster NGC 3532. Some of the stars still shine with a
hot bluish colour, but many of the more massive ones have become red
giants and glow with a rich orange hue.
NGC 3532 is a bright open cluster located some 1300 light-years away in the constellation of Carina (The
Keel of the ship Argo). It is informally known as the Wishing Well
Cluster, as it resembles scattered silver coins which have been dropped
into a well. It is also referred to as the Football Cluster, although
how appropriate this is depends on which side of the Atlantic you live.
It acquired the name because of its oval shape, which citizens of
rugby-playing nations might see as resembling a rugby ball.
This very bright star cluster is easily seen with the naked eye from
the southern hemisphere. It was discovered by French astronomer Nicolas Louis de Lacaille
whilst observing from South Africa in 1752 and was catalogued three
years later in 1755. It is one of the most spectacular open star
clusters in the whole sky.
NGC 3532 covers an area of the sky that is almost twice the size of
the full Moon. It was described as a binary-rich cluster by John
Herschel who observed “several elegant double stars” here during his
stay in southern Africa in the 1830s. Of additional, much more recent,
historical relevance, NGC 3532 was the first target to be observed by
the NASA/ESA Hubble Space Telescope, on 20 May 1990.
This grouping of stars is about 300 million years old. This makes it middle-aged by open star cluster standards [1].
The cluster stars that started off with moderate masses are still
shining brightly with blue-white colours, but the more massive ones have
already exhausted their supplies of hydrogen fuel and have become red
giant stars. As a result the cluster appears rich in both blue and
orange stars. The most massive stars in the original cluster will have
already run through their brief but brilliant lives and exploded as
supernovae long ago. There are also numerous less conspicuous fainter
stars of lower mass that have longer lives and shine with yellow or red
hues. NGC 3532 consists of around 400 stars in total.
The background sky here in a rich part of the Milky Way is very
crowded with stars. Some glowing red gas is also apparent, as well as
subtle lanes of dust that block the view of more distant stars. These
are probably not connected to the cluster itself, which is old enough to
have cleared away any material in its surroundings long ago.
This image of NGC 3532 was captured by the Wide Field Imager instrument at ESO’s La Silla Observatory in February 2013.
Notes
[1] Stars with masses
many times greater than the Sun have lives of just a few million years,
the Sun is expected to live for about ten billion years and low-mass
stars have expected lives of hundreds of billions of years — much
greater than the current age of the Universe.
More Information
ESO is the foremost intergovernmental
astronomy organisation in Europe and the world’s most productive
ground-based astronomical observatory by far. It is supported by 15
countries: Austria, Belgium, Brazil, the Czech Republic, Denmark,
France, Finland, Germany, Italy, the Netherlands, Portugal, Spain,
Sweden, Switzerland and the United Kingdom. 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, the world’s most advanced visible-light astronomical
observatory and two survey telescopes. VISTA works in the infrared and
is the world’s largest survey telescope and the VLT Survey Telescope is
the largest telescope designed to exclusively survey the skies in
visible light. ESO is the European partner of a revolutionary
astronomical telescope ALMA, the largest astronomical project in
existence. ESO is currently planning the 39-metre European Extremely
Large optical/near-infrared Telescope, the E-ELT, which will become “the
world’s biggest eye on the sky”.
Links
- Photos of the MPG/ESO 2.2-metre telescope
- Other photos taken with the MPG/ESO 2.2-metre telescope
- Photos of La Silla
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
Source: ESO
