carbon stars


Also found in: Dictionary.

carbon stars

(C stars) Red giant stars of low temperature that have an over-abundance of carbon relative to oxygen in their surface layers. In cool stars carbon and oxygen atoms combine to form stable carbon monoxide, and in carbon stars the excess carbon can then form other molecules. Their spectra therefore show strong bands of carbon compounds, including C2, CN, and CH. All carbon stars undergo mass loss, enriching the interstellar medium with considerable carbon, some nitrogen and oxygen, and also s-process elements. In the earlier Harvard classification (see spectral types) carbon stars were divided into R stars and N stars : N stars are the ‘classical’ carbon stars, discovered spectroscopically by Angelo Secchi (1868). They are very cool and very luminous and many have been discovered in the Magellanic Clouds and other galaxies. They are observed to be losing mass rapidly and are much further evolved than the hotter less luminous R stars. The R stars are enriched in the isotopes 13C and 14N, but unlike most N stars, show no enhancement in s-process elements. See also R Coronae Borealis stars; S stars.
References in periodicals archive ?
La Superba is a carbon star, which means it's one of the deepest red stars in the sky.
Spectroscopic changes and the variable mean light of carbon stars Monthly Notices of the Royal Astronomical Society, 286, 839-847.
And finally, carbon stars are notoriously variable, not just in magnitude but in colour too, and it is probably no more than fortuitous that WZ Cas should happen to have one of the largest numerical values of (B-V) in the database consulted by Mr Ahad.
Decin and her colleagues now plan to extend the observations to other carbon stars.
Based on an analysis of 110 carbon stars dotted across the sky brighter than magnitude 8.5, (1) I have determined the double star WZ Cassiopeiae (Otto Struve 254) to be the system with the greatest colour contrast, both visually as well as numerically, out of all double stars in the sky.
Object Type RA (J2000.0) Dec GN 02.34.4 Emission Neb 0[2.sup.6] 36.1 -53[degrees]03' NGC 1252 Open Cluster 03 11.4 -57 38 NGC 1261 Glob Cluster 03 12.3 -55 13 TW Horologii Carbon star 03 12.6 -57 19 NGC 1433 Galaxy 03 42.0 -47 13 NGC 1448 Galaxy 03 44.5 -44 39 Arp Madore 1 Glob Cluster 03 55.0 -49 36 NGC 1510 Galaxy 04 03.5 -43 24 NGC 1512 Galaxy 04 03.9 -43 21 Object Mag Size GN 02.34.4 8.3 250" NGC 1252 8.4 20' NGC 1261 8.3 6.8' TW Horologii 5.7 NGC 1433 9.9 6.5' x 5.9' NGC 1448 10.7 7.6' x 1.7' Arp Madore 1 15.0 1' NGC 1510 12.7 0.9' x 0.9' NGC 1512 10.3 8.9' x 5.6'
Of all the stars recorded by 2MASS, the astronomers chose to analyze carbon stars first because of three remarkable properties.
But the reddest shades of orange can be found among the carbon stars: red giants (for the most part) that possess more carbon in their atmospheres than oxygen.
Thus, 119 Tauri remains firmly in second place in the league of all known red supergiants (which excludes carbon stars) and some have even started to refer to this star as the Ruby Star after my lead.
Stars more massive than the sun end their lives as carbon stars, which in our galaxy are a rich source of dust.
Double stars, Cepheid variable stars, Viewing galaxies, Black holes, Main-sequence stars, Globular clusters, Discovery of Proxima, Extra-solar planets, Open star clusters, Sub-giant stars, Nebulae, Yellow-dwarf star, Barred spiral galaxies, Galaxies and time, Close double stars, Coloured double stars, Super galaxy clusters, Mira variable stars, Giant stars, Carbon stars, Observing double stars, Solar type stars, Nicolas Louis de Lacaille, Astrophotography, Light year, Sub-dwarf stars, Venial equinox, Hot Jupiters, Delta-Scuti variable star, Apparent brightness.
Otherwise, the orbits of the carbon stars would spread out rather than remain in a circle, Ibata says.