Tag Archives: star clusters

NGC 1981 – The Secret Harem Revealed

Posted on by November 14, 2024

Due its proximity to very impressive neighbors, the open cluster ngc 1981 in Orion has never attracted my attention. The cluster has only 10 or so, sparsely distributed, young bright stars.

The multiple star system, Struve 750, is the northernmost star of the string of three stars, right above the Running Man.

The story goes that Aldebaran, failing to shoot one of the three zebras, was given the boot by the seven sisters. They weren’t impressed that he could not retrieve his arrow in fear of Betelgeuse who was as strong as a lion. So the arrow (which we know as Orion’s sword) is still lying there. Now I know why Betelgeuse would not allow Aldebaran to approach. He was actually guarding his own harem!

Gum 50 & Trumpler 23

Posted on by July 21, 2021

While working through South African astronomer, Magda Streicher’s, list of delightful asterisms to enjoy the pretty in the night sky, I have come across some very interesting deep-sky objects in the nearby regions of the sky.

I noticed a pinkish-reddish object to the north of asterism, Streicher 34. I ran the co-ordinates in Aladin Sky Atlas and identified this as Gum 50. Then another surprise! I also found the faint but destinctive open cluster, Trumpler 23 northeast of Gum 50. The cluster has an interesting shape and almost looks connected to Gum 50 by a string of stars. Could they be somehow connected?
If only I could understand what’s been written in scientific papers by Y M and Y P Georgelin and Veta Avedisova, I would have a clearer idea.

At one stage Avedisova placed Gum 50 and Trumpler 23 in the same star forming region. After measuring distances and determining spectral classes of the stars, the Georgelins cast doubt on whether the cluster was associated with Gum 50, which goes by RCW 99 as well.