mfoylan
Carbon Star - BL Orionis
A red giant whose spectrum is dominated by strong absorption bands of carbon-containing molecules. The Swan bands of C2 are especially prominent, with absorption by CN, CH, C3, SiC2, and C aII present to varying degrees, with often a strong sodium D line.
Carbon stars, also known as C stars, have carbon/oxygen ratios that are typically four to five times higher than those of normal red giants and show little trace of the light metal oxide bands that are the usual red giant hallmark. They resemble S stars in their relative proportion of heavy and light metals, but contain far more carbon in their upper layers. The carbon is likely the dredged-up ashes of nuclear helium burning in the stellar interior. Carbon stars lose a significant fraction of their total mass in the form of a stellar wind which ultimately enriches the interstellar medium – the source of material for future generations of stars.
Carbon stars were previously classified as stars of spectral type R (hotter, with surface temperatures of 4,000 to 5,000 K) and N (up to 10 times more luminous but cooler, with a temperature of about 3,000 K). They are typically associated with some circumstellar material in the form of sooty shells, disks, or clouds.
www.daviddarling.info/encyclopedia/C/carbon_star.html
Variability Type: LB
Slow irregular variables of late spectral types (K, M, C, S); as a rule, they are giants (CO Cyg). This type is also ascribed, in the GCVS, to slow red irregular variables in the case of unknown spectral types and luminosities.
Distance: 1,300 light-years
GSC 744:949, HIP 30564, HD 44984
RAJ200006 25 28.2
DEJ2000+14 43 19
+7.9 Magnitude at maximum brightness
+9.7 Magnitude at minimum
SpType: C6,3(Nb,Tc)
R-Bessell Photometric Filter: 10 seconds x6 exposures, flat fielded, aligned and median combined
G-Bessell Photometric Filter: 20 seconds x6 exposures, flat fielded, aligned and median combined
B-Bessell Photometric Filter: 45 seconds x6 exposures, flat fielded, aligned and median combined
B-V-R folder images were then aligned and stacked to give Master B, V and R images; these were then colour combined in CCDSoft v5
CCD Operating Temperature: -37 Degrees Centigrade
Field of View: 46 x 37 arcmins
Pixel Array: 1280 x 1024
Pixel Size: 16um x 16 um
Plate Scale: 2.17 arcsec/pixel
0.2-m SCT+SBIG STL 1301E CCD
f/ratio: 7.6
Date: 05th March 2016
Carbon Star - BL Orionis
A red giant whose spectrum is dominated by strong absorption bands of carbon-containing molecules. The Swan bands of C2 are especially prominent, with absorption by CN, CH, C3, SiC2, and C aII present to varying degrees, with often a strong sodium D line.
Carbon stars, also known as C stars, have carbon/oxygen ratios that are typically four to five times higher than those of normal red giants and show little trace of the light metal oxide bands that are the usual red giant hallmark. They resemble S stars in their relative proportion of heavy and light metals, but contain far more carbon in their upper layers. The carbon is likely the dredged-up ashes of nuclear helium burning in the stellar interior. Carbon stars lose a significant fraction of their total mass in the form of a stellar wind which ultimately enriches the interstellar medium – the source of material for future generations of stars.
Carbon stars were previously classified as stars of spectral type R (hotter, with surface temperatures of 4,000 to 5,000 K) and N (up to 10 times more luminous but cooler, with a temperature of about 3,000 K). They are typically associated with some circumstellar material in the form of sooty shells, disks, or clouds.
www.daviddarling.info/encyclopedia/C/carbon_star.html
Variability Type: LB
Slow irregular variables of late spectral types (K, M, C, S); as a rule, they are giants (CO Cyg). This type is also ascribed, in the GCVS, to slow red irregular variables in the case of unknown spectral types and luminosities.
Distance: 1,300 light-years
GSC 744:949, HIP 30564, HD 44984
RAJ200006 25 28.2
DEJ2000+14 43 19
+7.9 Magnitude at maximum brightness
+9.7 Magnitude at minimum
SpType: C6,3(Nb,Tc)
R-Bessell Photometric Filter: 10 seconds x6 exposures, flat fielded, aligned and median combined
G-Bessell Photometric Filter: 20 seconds x6 exposures, flat fielded, aligned and median combined
B-Bessell Photometric Filter: 45 seconds x6 exposures, flat fielded, aligned and median combined
B-V-R folder images were then aligned and stacked to give Master B, V and R images; these were then colour combined in CCDSoft v5
CCD Operating Temperature: -37 Degrees Centigrade
Field of View: 46 x 37 arcmins
Pixel Array: 1280 x 1024
Pixel Size: 16um x 16 um
Plate Scale: 2.17 arcsec/pixel
0.2-m SCT+SBIG STL 1301E CCD
f/ratio: 7.6
Date: 05th March 2016