Starship Asterisk*

Moonlady wrote:
T Lyrae, SAO 67087

Beyond wrote:Ok... so what's the-->C*

T-Lyrae A Blood Red Carbon Star
http://www.seeintospace.com/charts/charts.html

The first time I saw this star it startled me. It really is red. It's small and you'll have to look carefully to find it but once you do, you'll know it when you see it.

Carbon Stars are a rare type of old, evolved stars that contain more carbon than oxygen. Most stars contain little carbon or oxygen, both of which are formed late in the life of a star after the hydrogen in the star’s core is exhausted and the star begins burning helium. Stars that burn helium grow much larger than their original size and hence are known as red giant or red supergiant stars. Most carbon stars are cool red giant stars.

In most giant stars, the dominant nuclear reaction that fuels the star is the fusion of three helium nuclei to create one carbon nucleus. The carbon atoms participate in other reactions that create oxygen and nitrogen. The normal sequence of reactions produces more oxygen than carbon. In carbon stars, however, some additional or alternative reaction sequence must exist, because these stars contain more carbon than oxygen. Carbon stars also contain unusual ratios of carbon isotopes (carbon atoms with different atomic weights), which is another indication that nuclear reactions other than those of normal stars occur within them.

Something to think about. ALL known life forms are carbon based. No carbon, no life. Yet, carbon is not abundant in the universe. Had a star not gone through its life-cycle and exploded distributing carbon and other elements into our little corner of the Milky Way Galaxy, we wouldn't be here. There would be no solid planets---perhaps only gas giants (like Jupiter) or a star with no attending planets.

What does this mean? It means just because there are billions and billions of stars does not mean they all have sufficient elements nearby to form planets which can support life. In fact, that could be a rather rare event.

It also means that you are literally made of star dust. Had a star not created your carbon, you wouldn't be here.

So let's find T-Lyrae and see a carbon star!  One note...the bigger the scope, the redder this star will look. Why? As you gather more light, you gather more color. But still, this rare beauty will stand out beautifully in the smallest telescopes.

You wrote
I don't know why Delta Cephei never got a Latin letter to signal its variability.

http://www.iau.org/public/naming/
THE INTERNATIONAL ASTRONOMICAL UNION
Unfortunately, the Greek alphabet has only 24 letters, and many constellations contain many more stars, even if the naming is restricted to those visible to the naked eye. Johann Bayer then employed low case letters from "a" to "z" and then upper case letters from "A" to "Z" for the stars number 25 to 50 and 51 to 76 in each constellation, respectively...

Variable stars

A notable nomenclature scheme has been developed for variable stars, by Friedrich Wilhelm Argelander in 1862. He proposed to reserve the letters "R" to "Z" for naming the variable stars in each constellation, as Bayer's naming scheme had left these over in each case (and some constellations had a star "Q" in this scheme, e.g. Centaurus, Puppis and Vela).

At that time, the 9 possible names per constellation seemed more than enough, as the number of known variables was small. However, it turned out that it was completely insufficient, and thus the scheme was first extended to two-letter designations, then even to numbers.

Eventually, variables are named as follows: the designation of variables consists of one or two letters and the constellation name (such as U Sagittarii or RR Lyrae) or a number preceded by "V" and the constellation name (e.g., V 1500 Cygni). In each constellation, the first variable discovered is assigned the letter "R" and the genitive of the constellation name, e.g., "R Andromedae" (a long period variable), the second one is "S" (e.g., "S Andromedae" is the supernova which occured in the Andromeda galaxy, M31), and so on up to "Z" for number 9; then the tenth variable is assigned "RR", followed by "RS" etc up to "RZ", "SS" (not "RS"), *etc. up to "SZ", and so on up to "YY", "YZ", "ZZ", and then "AA", "AB", etc to "AZ", "BB" to "BZ", up to "QQ" to "QZ" (where the letter "J" is not used to avoid confusion with the letter "I").

Counting, this scheme provides 334 designations for each constellation, and variables starting from number 335 are designated "V 335", "V 336" etc. Those already assigned a Bayer designation are not given a new name according to this scheme (such as Delta Cephei, Beta Lyrae, Beta Persei, or Omicron Ceti).

Variable stars are classified by types which are then named after one typical representative, e.g., "Mira stars", "RR Lyrae stars", or "Delta Cephei stars" (often called "Cepheids" in deviation from the usual scheme).

MargaritaMc wrote: * That seems a misprint, but it is what is written on the IAU page.

http://en.wikipedia.org/wiki/Vega wrote:
Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727 when the declination will be +86°14'.

bystander wrote: They probably meant "SR" not "RS"