Ground-based view of the sky around IC 63
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Zoom-in on the Ghost Nebula
Pan across a cosmic ghost
About 550 light-years away in the
constellation of Cassiopeia lies IC 63, a stunning and slightly eerie
nebula. Also known as the ghost of Cassiopeia, IC 63 is being shaped by
radiation from a nearby unpredictably variable star, Gamma Cassiopeiae,
which is slowly eroding away the ghostly cloud of dust and gas. This
celestial ghost makes the perfect backdrop for the upcoming feast of All
Hallow's Eve — better known as Halloween.
The constellation of Cassiopeia, named after a vain queen
in Greek mythology, forms the easily recognisable “W” shape in the
night sky. The central point of the W is marked by a dramatic star named
Gamma Cassiopeiae.
The remarkable Gamma Cassiopeiae is a blue-white subgiant variable
star that is surrounded by a gaseous disc. This star is 19 times more
massive and 65 000 times brighter than our Sun. It also rotates at the
incredible speed of 1.6 million kilometres per hour — more than 200
times faster than our parent star. This frenzied rotation gives it a
squashed appearance. The fast rotation causes eruptions of mass from the
star into a surrounding disk. This mass loss is related to the observed
brightness variations.
The radiation of Gamma Cassiopeiae is so powerful that it even
affects IC 63, sometimes nicknamed the Ghost Nebula, that lies several
light years away from the star. IC 63 is visible in this image taken by
the NASA/ESA Hubble Space Telescope.
The colours in the eerie nebula showcase how the nebula is affected by the powerful radiation from the distant star. The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation — visible in red in this image.
The colours in the eerie nebula showcase how the nebula is affected by the powerful radiation from the distant star. The hydrogen within IC 63 is being bombarded with ultraviolet radiation from Gamma Cassiopeiae, causing its electrons to gain energy which they later release as hydrogen-alpha radiation — visible in red in this image.
This hydrogen-alpha radiation makes IC 63 an emission nebula,
but we also see blue light in this image. This is light from Gamma
Cassiopeiae that has been reflected by dust particles in the nebula,
meaning that IC 63 is also a reflection nebula.
This colourful and ghostly nebula is slowly dissipating under the influence of ultraviolet radiation
from Gamma Cassiopeiae. However, IC 63 is not the only object under the
influence of the mighty star. It is part of a much larger nebulous
region surrounding Gamma Cassiopeiae that measures approximately two
degrees on the sky — roughly four times as wide as the full Moon.
This region is best seen from the Northern Hemisphere during autumn
and winter. Though it is high in the sky and visible all year round from
Europe, it is very dim, so observing it requires a fairly large
telescope and dark skies.
From above Earth’s atmosphere, Hubble gives us a view that we cannot
hope to see with our eyes. This photo is possibly the most detailed
image that has ever been taken of IC 63, and it beautifully showcases
Hubble’s capabilities.
More Information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA
Links
Contact
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching, Germany
Tel: +49 176 62397500
Email: mjaeger@partner.eso.org
More Information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA
Links
Contact
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching, Germany
Tel: +49 176 62397500
Email: mjaeger@partner.eso.org
Source: ESA/Hubble/News
