I will post a list of about 20 or so of my favourite "red" stars for anyone that is interested, tomorrow when I have a bit more time.
Hi all,
Attached is a list of "red" stars with more southerly declinations and easily visible from all Southern Latitudes. There are countless "other" lists floating around that list stars visible from more northern or "both" hemispheres.
I have also included 2 other scientifically interesting stars at the bottom of the list. Barnard's Star (GL699) in Ophiuchus and Kapteyn's Star (VZ Pictoris) in Pictor. Barnard's Star has the highest known proper motion (fastest moving) of any star. Prior to the discovery of Barnard's Star, this title was held by Kapteyn's Star.
It is worth noting that whilst I have listed the stars down the page in order of magnitude, their magnitudes can fluctuate dramatically at different stages of their cycle. For instance the star at the top of the list, Mira (Omicron Ceti) fluctuates between magnitude 2 and 10.1
Attached is a list of "red" stars with more southerly declinations and easily visible from all Southern Latitudes. John B
Thanks a good short list.
Just curious.
Q: Any personal objections to W Pic or X TrA here?
Do you think we should combine the other lists and targets into a more definitive list here?
A detailed Carbon Stars list
for the enthusiast observer
all difficult for me with protanopic vision
With the kindest respect...
1) Is there any reason why the range of stars are only between +40 and -40 declination?
2) That HIP 63955 with a K0 spectral class is in this list. I.e. The B-V is only +1.18 - and is not very red.
3) What is the source of the magnitude range and the Spectral Class?
Did you get this list from SIMBAD, as HIP 63955 is also wrongly given as a Carbon Star (which it is not)? In this instance, the CN tacked on the end is the chemical Cyogen lines not is not Carbon lines.
Also HIP 85148 is spectral class A0 !!
Note: I have attached a pdf file of your list, with highlights (in Red) some of the questionable data. Underlined stars probably shouldn't be in the list.
Glenn and all
This catalogue you quote is rather out of date, and there has been much research into these stars since. I.e. Most of the variables., for example are not even labelled.
As to the "General Catalog of galactic Carbon stars, 3d Ed. (Alksnis+ 2001) is often quoted http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/239, this is a pretty good source, though the magnitudes and spectral classes have been superseded in many sources.
I should comment, that Carbon stars are not necessarily the reddest ones, as dust absorption can also be significant.
Once classic example is 8.47V magnitude R Fornacis, whose B-V is an extraordinary 5.44 !! It is classed as a Mira variable, whose variations are 7.5v to 13.0v every 388.73 days, whose spectral class is C4,3e(Ne).
The best and latest source is actually "Carbon-rich giants in the HR diagram" (Bergeat+, 2002) You can source this catalogue at; http://vizier.u-strasbg.fr/viz-bin/V.../A%2bA/390/967
and select under Maximum Entries per Table as 1000 (instead of 50) Once shown, you can sort the columns with the little arrows, or query each star under "SIMBAD" Column.
This catalogue list 14 Carbon photometric groups that are based not just on spectra. ("Group" in the table to search) Hot carbon stars in fact are not the reddest. You will find in the source mentioned here, that Carbon stars are list as CV (Carbon variables), bluer to redder from CV1 to CV7. CV7's are the reddest stars known.
W Pic is CV6, while X TrA is CV5. R For is CV 7 (above). Just twenty seven CV7's are known.
The main Catalogue description for this data is at; http://cdsarc.u-strasbg.fr/viz-bin/Cat?J/A%2bA/390/967
Thanks a good short list.
Just curious.
Q: Any personal objections to W Pic or X TrA here?
Do you think we should combine the other lists and targets into a more definitive list here?
Hi,
I actually put together a select list of 600 DSO's visible from Southern latitudes, for the benefit of the regular groups of US observers that myself and a couple of friends entertain here on a regular basis. I put the list together about 4 years ago. To date it has only been circulated to the "Aussie" 3RF members and the respective visiting American observers. I "added" a handful of "red" stars almost as an afterthought to round out the diversity of targets in the list, when I was putting it together. The list of "red" stars I provided is merely an edit from my list of 600 DSO's. It is highly likely I have missed a couple of good ones.
I would be more than happy for you to add to the list as you see fit and ultimately compile a more complete list of "red" Southern Skies stars to be archived on IIS database.
Enchilada's post was extremely interesting, and the links were well worth following - V Hya is CV6, which puts it right up there on that particular scale. But I suspect for ordinary visual observers, your aperture, the magnification you're using, the sky conditions and your eyesight will be big contributors to what you see as the reddest, so there's room for lots of opinions on this! Great thread!
The last visual observation on the 19th January finds it is 9.2v magnitude and falling. It reached its peak brightness in mid-November 2008.
Based on the 530.7 day period, I'd say you will find it about 10th magnitude. I wouldn't dally though, as by around May it will not be well placed. The latest AAVSO data, shows the observations as per the attachment. As you can see it is fading fast. (See the black line)
Thanks guys, for the info and lists of carbon stars ... all very interesting, and will get out to check when these clouds clear ... prob another 6 weeks!!!
Ummm ... the B-V (am not familiar with this) is a reference related to the colour, and the lower the number, the stronger the red ... is this right??
Ok, after a bit of reading I see that the star is observed through special B and V filters, and subtracting the 2 values gives you the colour index. Blue stars have a negative index, whereas red stars have an index from 0-3.
Looking at a chart - R leporis 2.7/U Hya 2.7/CE tauri 2.08/Betelgeuse 1.85/Antares 1.83
Ummm ... the B-V (am not familiar with this) is a reference related to the colour, and the lower the number, the stronger the red ... is this right??3
Liz. Your summary is quite correct, but here is some further information to aid your thinking.
B-V magnitudes (or B-V Colour Index - or sometimes Total Colour Index) is very simply are a way of measuring colours in stars. It comprises of two separate magnitudes, which are measured through specialised filter, either using a photoelectric photometer (an instrument to measure the intensity of light) or photographically. The B stands for the Blue filter or band, while the V is the Visual filter or band. These filters were introduced by H. Johnston and W. Morgan in 1953. (Photographically, this effect was known in the 1890's, whose colours could be identified using a blue and visual photographic plate. It was not employed successfully for measuring colours until the 1920's, due to the blue sensitivity of the plates at the time.)
Other filters and colours can be obtained too, such as U (Ultra-violet), R (Red) and I (Infra-red) - collectively known as the UBVRI system or the Johnston-Morgan standards. Colours can also be expressed as U-B or V-I, for example. All well and good.
Now the magnitudes measured in the B and V can be subtracted from each other, and the difference in magnitude becomes the B-V value. So;
Blue stars have values of about -0.2 (some are negative up to about -0.38, from memory)
White stars are about 0.00, where +0.00 corresponds to A0. This is called the white point - meaning essentially no colour (even though the whte light may be broken into different colours of the spectrum
Yellow stars (F6 spectral class star are about +0.43)
Orange stars are about +0.80
Red stars are about +1.20
Deep-red stars (carbon stars) are usually below +2.00
The reddest stars known have B-V values of about +5.5
If some star has a B-V of +0.43, then the magnitude in the B filter appears +0.43 magnitude brighter than the V magnitude.
Now colours from star travel through space, and as they travel the light becomes redder. It is cause by gas and dust that lies between us and the star or object. Therefore a correction must be accounted, often in term of magnitudes per kiloparsec, which is either estimated (or measurable with another photometric system used by astronomer). Values are typically about +0.04 magnitudes extinction from the absorption of light. When corrected, this is given as (B-V) or (B-V)0 (zero as subscript). Most cases seen to the naked-eye are usual just disregarded, but sometimes they are not.
Galaxies can have B-V colours (usually solar-like at about +0.4), and in this case (B-V)0 accounts for the redshift by the Hubble expansion of the Universe.
Probably one last thing, B-V is proportional to the spectral type and the surface temperature of stars, and can be used as a rough estimate.
An examples of its uses in astronomy are, By plotting B-V versus (x-axis /bottom) the V magnitude (y-axis vertical axis) produces the so called colour-magnitude diagram, which can be usefully employed to tell us something about the evolution of the stars.
To quote David Malin in the Encyclopaedia of Astronomy "The Colour of Stars";
"The colors of the stars are real but not apparent. They are not seen by the unaided eye because stars are both intrinsically faint and at the same time minute points of light, almost always observed by a more-or-less dark-adapted eye. However, the colors of the stars are an important and quantifiable observational property that is indicative of their surface temperature. This in turn is a function of a star’s mass and its evolutionary status. These ideas are brought together in the well-known color magnitude diagram, a cornerstone of stellar astrophysics."
Anyway, hope all this helps you...
NOTE: If you are interested in the perception of star colours, you can read a through article on Star Colours at;
Glen,
Thanks for the HIP and Tycho lists. However, in terms of its usefulness for Carbon Stars it is probably not the best available because of the photometry range that could be of the satellite. Furthermore, as most are variables, many were therefore missed altogether. Hence, why we see the number of independent catalogues through the literature.
[If I can recall, this is mentioned in the paper by VandenBerg and Clems entitled "Empirically Constrained Color-Temperature Relations (I or II)" in 2003.]
A definitive list can probably only be obtained from various sources, which will need to be constrained on magnitudes and B-V.
I generally suggest a maximum limit of 9.0 magnitude, and B-V above +2.5, and a minimum magnitude above, say, 13th.
Mag 7 (var).
ISS Carbon Star List
)
B-V Colour Index
