Let's see. Here we have a mapped color image of a nebula that is 8,000 light-years distant but still large enough in the sky to cover the full Moon. Sounds big. This thing must have a powerful stellar engine driving it. What is said about the stellar engine?
APOD Robot wrote:
Open star cluster NGC 7380 is still embedded in its natal cloud of interstellar gas and dust popularly known as the Wizard Nebula.
NGC 7380 (also known as the Wizard Nebula) is an open cluster discovered by Caroline Herschel in 1787.
Located 7200 light years away, the Wizard nebula, surrounds developing open star cluster NGC 7380. Visually, the interplay of stars, gas, and dust has created a shape that appears to some like a fictional medieval sorcerer. The active star forming region spans about 100 light years, making it appear larger than the angular extent of the Moon.
Hmmm. More enlightenment.
Sneh Lata, A. K. Pandey, Neelam Panwar, W. P. Chen, M. R. Samal and J. C. Pandey
This cluster has been an interesting and important object because it contains a massive binary system DH Cep (=HD 215835; V = 8.58) which is a double-lined, massive spectroscopic binary having a pair of O5–6 V stars with an orbital period of 2.111 d (Pearce 1949; Lines et al. 1986; Semeniuk 1991). This star is located at the centre of the cluster and found to be an ionizing star for the emission nebula (Underhill 1969).
Well, that's by far the most enlightenment I've had so far. What is said about the other massive members of NGC 7380?
We find NGC 7380 an interesting object as it is an extremely young open cluster which contains several PMS stars, massive stars O/B-type stars as well as other main-sequence (MS) stars.
Yes, that's enlightening... maybe...
So I'm left with a single star to find information about, namely binary O-type star DH Cephei.
Based on the star's spectral type of O5.5 , DH Cephei's colour and type is blue - white variable star. The star has a B-V Colour Index of 0.33 which means the star's temperature is about 6,656 Kelvin.
The temperature of an O-type star is 30,000 K or more. It ought to have a B-V color index or -0.20 or more. If it has a B-V index of +0.33, that just means that the star is heavily reddened by dust that is located between ourselves and the star.
I think perhaps the most useful thing I learned here is that DH Cephei is the chief ionizing star of NGC 7380, in the same way that Theta 1 C Orionis
is the chief ionizing star of the Orion Nebula.