Constellations: Chamaeleon 'the Chameleon' Content from the guide to life, the universe and everything

Constellations: Chamaeleon 'the Chameleon'

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The shield of the Science, Mathematics and Engineering faculty of the h2g2 University.Constellations: Overview | Andromeda | Antlia | Apus | Aquarius | Aquila | Ara | Aries | Auriga | Boötes | Caelum
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Karma karma karma karma karma chameleon
You come and go
You come and go
– 'Karma Chameleon' by Culture Club

Latin:Chamæleon
Genitive:Chamæleontis
Short form:Cha
Area:132 sq deg
Co-ordinates1:Right Ascension 11h, Declination −80°
Origin:Modern (late 16th Century)

Chamæleon the chameleon (because it is well hidden) is in a nondescript section of the sky with no bright stars; its most notable feature is the rather gorgeous cosmic tornado HH49/50 (see 'Deep-sky Objects'). This portion of sky also contains the Chamæleon Dark Clouds, around 500 light years'2 distance from Earth. It is a stellar nursery, where stars known as T Tauri-types3 are being created. The Clouds, composed of mostly gas and dust, have a mass of approximately half a million Suns.

Bordered by Musca, Carina, Volans, Mensa, Octans and Apus, Chamæleon is one of a dozen constellations delineated by Dutch astronomers Pieter Dirkszoon Keyser and Frederick de Houtman during their voyage to the southern seas between 1595 and 1597 on board the Hollandia. The chameleon first appeared in Johann Bayer's Uranometria (star catalogue) of 1603. Even the most fertile imagination struggles to form the shape of a lizard from this star group, Bode's drawing more resembles a dinosaur with a crab's pincer for a beak.

Stars

Stars are known by their 'Bayer designation', that is a Greek letter combined with the genitive of the constellation name. Some stars have proper names as well, for example, alpha Lyrae is a very well-known star called Vega, but there are no named stars in Chamæleon. Other stars, like HD 63454, are known by their catalogue number. Newly discovered variable stars like ST Chamæleontis are given upper case English letters.

Stars of Chamæleon

Alpha Chamæleontis is a relative neighbour at just 64 light years distant. Although it is a rare white giant star, it is giving off the luminosity and temperature range of a much-younger dwarf. Chemical analysis of its spectrum provides us with the data 'high lithium' and 'high nitrogen', when usually it is one or the other. Such a puzzle adds interest to an otherwise boring piece of the sky. Is it a young star still cooking, or a dying older star swelling prior to exploding as a nova?

Delta, epsilon, mu and theta Chamæleontis are all binary star systems.

ST Chamæleontis is a binary system comprising a cataclysmic variable star (CV) and a 'normal' star, and it is the companion's periastron (closest orbital proximity) which is causing the outbursts. ST Chamæleontis underwent its most recent outburst on 3 September, 2008.

R Chamæleontis is a Mira-type variable. This means that it belongs to the same class as the star named Mira (omicron Ceti), which is the prototype of this class of variables. R Chamæleontis varies between magnitude +7.5 and +14.

Star Table

StarDesignationBrightness (m)Distance
(light years)
Spectral classification
and/or comments
αalpha Cha+4.0564White giant
γgamma Cha+4.1 var400Red giant
βbeta Cha+4.2 var270Blue-white dwarf
θtheta Cha+4.3 var150Binary
εepsilon Cha+4.9 var360Binary
κkappa Cha+5.04 var400Orange giant
ζzeta Cha+5.07 var500Blue-white dwarf
ιiota Cha+5.3 var104Yellow-white subgiant
δdelta Cha+5.4 var350 avBinary
ηeta Cha+5.46316Part of cluster Mamajek 1
μ1mu1 Cha+5.5 var400White subgiant
μ2mu2 Cha+6.6560Yellow giant
STST Cha+12.8 to +17.6450CV
RR Cha+7.5 to +14300Mira-type variable
HD 63454HD 63454+9.3 var116Orange dwarf/
has a planet

Deep-sky Objects

The NGC was compiled by John Louis Emil Dreyer (the director of the Armagh Observatory from 1882 - 1916). This was later expanded to include newer discoveries, and is being continually updated as the NGC/IC project. Newer discoveries are listed in different catalogues.

NGC 3195 is an unusual planetary nebula with an irregular inner disk of various coloured stripes (including pink, green and white), radiating out from the central star like a multicoloured flowerhead. Sir Patrick Moore included NGC 3195 in his 'challenge for backyard astronomers' catalogue as Caldwell 109.

When IC 2631 was first discovered it was registered as an emission nebula. When the NGC/IC project was undertaken the data was revised, and IC 2631 now appears as 'Diffuse Nebula or Supernova Remnant'. Only the original data is recorded in the table below.

The Eta Chamæleontis Cluster (also catalogued Mamajek 1) is an open star cluster which was discovered in 1999.

The molecular cloud Chamæleon I contains the highly photogenic 'cosmic tornado' HH (Herbig-Haro) 49/50.

Deep-sky Table

Catalogue or NameTypeBrightness (m)Remarks
Eta Chamæleontis ClusterOpen cluster+6 var50+ stars
NGC 3195Planetary nebula+10Caldwell 109
NGC 2915Galaxy+12.6Dwarf
NGC 3149Galaxy+13.1Spiral
NGC 3620Galaxy+15.3Elongated spiral
E 3Globular cluster+11.35One of the faintest known
IC 2631Emission nebula+9Now reclassified
HH 49/50Emission nebula+12Part of Chamæleon I molecular cloud

Extrasolar Planets in Chamæleon

One extrasolar planetary system has been found in this constellation up to 2008. The orbital period given in the table below is the time the planet takes to orbit its parent star, which we know of as a year. The mass of the extrasolar planet is compared to that of Jupiter, our Solar System's largest planet, known by astronomers as the 'Jovian scale'. HD 63454 is an orange dwarf and its planet HD 63454 b is a gas giant which orbits its star so closely (its year lasts less than three Earth days) that it belongs to the class 'hot Jupiter'.

Extrasolar Planets Table

Star name or
catalogue number
Planet
catalogue number
Planet mass
(Jovian scale)
Orbital period
(Earth days)
Year of discoveryComments
HD 63454HD 63454 b0.382.822005Hot Jupiter

Down to Earth

Chiuta4 and the Chameleon's message is an African myth which concerns the tale of an all-powerful being who creates life, collects souls in death and controls violent occurrences like earthquakes and stormy weather. The chameleon and the lizard were messengers of Chiuta, who raced to do his bidding at the beginning of time: informing men of their fate. The chameleon was to tell men that when they died their souls would return, but the lizard carried the message that no-one returned from death. Sorrowfully, the lizard won the race and as it had been acknowledged as the word of Chiuta, death was accepted as the fate of every man.

Chameleons in Nature

Chameleons are members of the lizard family Chamæleonidae, order squamata, suborder iguania. Their ability to change skin colour and tone to blend into the background to escape predators, attract a mate or just express a mood is legendary. They are also very distinctive for their long extensible tongue and their protruding eyes, which they can rotate independently. Chameleons, as well as some other lizards, have a third eye that can sense and pick up light which humans can't see.

Other creatures who also share the ability to camouflage themselves are cephalopods, the goldenrod crab spider (Misumena vatia), goldbugs (Golden tortoise beetles), seahorses, fish like flounders and some varieties of octopus5, although these are said to be chameleon-like rather than be called chameleons.

1Current IAU guidelines use a plus sign (+) for northern constellations and a minus sign (−) for southern ones.2A light year is the distance light travels in one year, roughly 5.88 trillion miles or 9.46 trillion km.3T Tauri-types are a class of variable stars named after their prototype T Tauri.4Sometimes called Chandu.5The Mimic octopus Thaumoctopus mimicus can actually impersonate other sea creatures as well as change colour.

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