continued from Starlit Sky: 9. Gemini, the twins
Let us now try and find out more about the constellation Cancer, called Karkatakam or Karka, the 4th constellation in the Indian Astrological system. This constellation has one of the faintest stars with apparent magnification not more than 4. So they are not visible to naked eye. On a moonless night, this will look like a faint beehive or a small vague cloud.
The Cancer is placed to the east of Gemini.
Viewed with a telescope it looks like a crab.
The star Asellus Australis is in the middle of the constellation. It is somewhat brighter than the others.It is an orange giant star that is almost 180 light years from us.
It is called Pushyami star in the Indian Astrological system. Pushyami is one of the 27 stars that are of importance in the Indian system.
Asellus Australis is next to the the Beehive Cluster. The Beehive Cluster, also called Praesepe, is the nearest open cluster to the solar system. On a cloudless, dark night, this cluster, containing more stars than other clusters, looks like a nebula. It is one of the oldest celestial objects studied by humans. One of the first objects studied in detail through his telescope by Galileo was this beehive cluster. The ancient astronomer Ptolemy called it the “nebulous breast of Cancer”.
An open cluster is a collection of thousands of stars that are originating from the same molecular mass of star cloud. So roughly all these stars will be of the same age. They are loosely bound by gravity.
There are more than a thousand open clusters found in the milky way galaxy till now. Open clusters are found in galaxies that have new stars taking birth.
to be continued………………