Proyecto Astronómico Constelación Cruz del Sur southern_cross_colegio_cristobal_colon | Page 6

NGC 4755 is made up of diverse stars from which we highlight the following:
Table 7 - Source: http://simbad.u-strasbg.fr/Simbad
1
2
3
4
5
6
Name
HD 111990
SAO 252075
HD 111904
SAO 252073
HD 111934
HD 111973
Star type
Star in Double System
Ellipsoidal variable Star
Variable Star
Variable Star of irregular type
Variable Star
Star in Cluster
B mag
7.01
8.165
6.09
9.82
7.15
6.10
V mag
6.77
7.962
5.80
7.66
6.91
5.9
Spectral class
B1B2Ib
B0.5 Vn
B9Ia
M2Iab
B2Ib
B5Ia
The most remarkable dark nebula of the South, located in the Southern Cross, is the Coal
Sack. This nebula is on the galactic plane, about 150 pc from the Sun [6]. It is known since
prehistory in this hemisphere. It was observed in 1499 by Vicente Yáñez Pinzón [10].
Some data about this nebula:
Table8 - Source: http://www.seds.org/messier/xtra/ngc/n4755.html
Right ascension
Declination
Distance
Apparent size
12h 52’
-63 degrees18’
2000 light years
420 by 240 arcmin
This nebula is composed of stellar dust that blocks the path of light. Here we see the Coal
Sack (in Spanish: Saco de Carbón) in sheer splendour:
Image by astrophotographer Pedro Aguirre V. (http://astrosurf.com/pedro)
III. The Southern Cross in comparison to the Northern Cross.
Image: http://faculty.rmwc.edu/tmichalik/mlkywayc.htm