The Dragon’s Egg

Constellation: Norma

The “Dragon’s Egg” is an ejected, axially symmetric (bipolar) circumstellar emission nebula in the constellation Norma. It is about 7’500 years old and spans about 4 Ly. At its center is the spectroscopic binary star HD 148937 located about 3’800 Ly away and the only galactic O6f?p star surrounded by a nebula. It is the brightest and hottest massive star (50–60 solar masses) to possess a strong magnetic field. It now consists of two stars. It appears that one of the two stars in the system is about 1.5 million years younger than the other and may be the result of a star merger, which may have resulted in the formation of the surrounding nebula and the magnetic star (link). NGC 6164/6165 has an extensive faint outer halo consisting mainly of oxygen and some hydrogen emission in this image. Expanding into the surrounding interstellar medium, the material in the halo is likely from an earlier active phase of the O star. Link to interactive sky chart.

Telescope & Mount:

Planewave CDK14 on a Paramount MX mount.

Imaging:

Camera: Player One Zeus-Mono (bin 2×2)

Data:
Ha: 102x600s
O3: 72x600s
S2: 103x600s

Stars:
Red: 60x60s
Green: 67x60s
Blue: 60x60s

Total integration time: 49h 17′