NASA Astronomy Picture of the Day 13 April 2023: Globular Star Cluster NGC 2419

Globular clusters are stable, tightly bound groups of tens of thousands to millions of stars that are associated with all types of galaxies. According to NASA, it is possible that globular star clusters once ruled the Milky Way. Back in the old days, back when our Galaxy first formed, perhaps thousands of globular clusters roamed our Galaxy. Today, there are less than 200 left.

Today’s NASA Astronomy Picture of the Day is the globular star cluster NGC 2419. It is a multi-generational star cluster located about 300,000 light-years away towards the constellation of Lynx. According to NASA, the stars populating globular clusters are very similar because they formed at roughly the same time and because of this, they tend to display similar properties.

Tech which helped capture the image

The image was captured by the Hubble Space Telescope which is run by NASA and ESA in collaboration. This stunning discovery by the Hubble Telescope further proves the capabilities of the Hubble Space Telescope. Despite being nearly 3 decades old, it still amazes us with stunning images of far-off celestial objects.

To capture such objects, Hubble has advanced optical instruments such as the Advanced Camera for Surveys and Wide Field Camera 3. The Advanced Camera for Surveys (ACS) was primarily designed to survey large areas of the sky at visible and red wavelengths with 10 times greater efficiency than the earlier premier Hubble camera. It has certainly proved fruitful as most of Hubble's images have been captured by the ACS.

How is NGC 2419 different?

According to NASA, the stars in the globular star cluster NGC 2419 do not exhibit similar properties. It holds two separate populations of red giant stars, and one is unusually helium rich. Other stars of this cluster hold varied elements too.

NASA’s description of the picture

Stars of the globular cluster NGC 2419 are packed into this Hubble Space Telescope field of view toward the mostly stealthy constellation Lynx. The two brighter spiky stars near the edge of the frame are within our own galaxy. NGC 2419 itself is remote though, some 300,000 light-years away. In comparison, the Milky Way's satellite galaxy, the Large Magellanic Cloud, is only about 160,000 light-years distant. Roughly similar to other large globular star clusters like Omega Centauri, NGC 2419 is intrinsically bright, but appears faint because it is so far away. Its extreme distance makes it difficult to study and compare its properties with other globular clusters that roam the halo of our Milky Way galaxy.

Sometimes called "the Intergalactic Wanderer", NGC 2419 really does seem to have come from beyond the Milky Way. Measurements of the cluster's motion through space suggest it once belonged to the Sagittarius dwarf spheroidal galaxy, another small satellite galaxy being disrupted by repeated encounters with the much larger Milky Way.