Figure 18-20: R I V U X G
A Young Star Cluster and Its H-R Diagram (a) This image shows the young star cluster NGC 2264 in a reddish H II region known as the Fox Fur Nebula. Stars within the cluster provide the ultraviolet light that powers this emission nebula. The cluster lies about 800 pc (2600 ly) from Earth. (b) Each dot plotted on this H-R diagram represents a star in NGC 2264 whose luminosity and surface temperature have been determined. This star cluster probably started forming only 2 million years ago, and its lower-mass stars have not yet reached the main sequence.
A Young Star Cluster and Its H-R Diagram (a) This image shows the young star cluster NGC 2264 in a reddish H II region known as the Fox Fur Nebula. Stars within the cluster provide the ultraviolet light that powers this emission nebula. The cluster lies about 800 pc (2600 ly) from Earth. (b) Each dot plotted on this H-R diagram represents a star in NGC 2264 whose luminosity and surface temperature have been determined. This star cluster probably started forming only 2 million years ago, and its lower-mass stars have not yet reached the main sequence.
(a: © 2004–2013 R. Jay GaBany, Cosmotography.com)