You can visit the Astromancer link here

My chosen star cluster is NGC 6025, or otherwise known as its designation in the Caldwell catalogue – Caldwell 95. Amongst the Caldwell designation, there have been many other categorizations of this star from Collinder, Melotte, Lacaille III, and Dunlop. (Wiki, 2024)

NGc 6025 is a intermediate open star cluster found in H II region of the southern Triangulum Australe constellation. The H II region is interstellar matter consisting of ionized hydrogen atoms, describing the chemical structure of NGC 6025. (Britannica, 2024)

This star cluster was first discovered by the French Astronomer Abbe Lacaille in 1751, as one of the 10,000 stars he observed during a 4 year expedition to South Africa(Wiki, 2024). An interesting feature of this cluster, is that its stated to be a decent object to find with binoculars. In 1994, Sven Kohle was able to take a color photograph of this object from Cerro Tololo, Chile with an SLR camera fitted with 50mm f/4.0 lens, 1 hour exposure and ISO 400 film. Super cool stuff! (1998, Seds.org)

For this analysis, determining NGC 6025 relationshipsS with metallicity, color and age required 15 images of the star cluster. These were observed through the Robotic Telescope network known as Skynet. There were 5 observations taken in Blue, Violet and Red Filters taken from Prompt 6 telescope in Cerro Tololo, Chile. B and V filters were taken with 9 sec exposures and R with 6 sec exposures.  Thanks to the Cerro Tololo Inter-American Observatory, I was able to highly detailed information to start my calculations.

After collecting these images, I used Afterglow and Cluster Astromancer – the partnered star analysis online software – to extract and analyze data from the cluster.

For the basic results, I found a PM RA of -2.94, PM DEC of -3.06, Distance of 0.7kpc, an age of 158.47 Million years (log(age) 8.2), and Reddening of 0.19. An important detail to note, that upon my submission to astromancer, my determined metallicity was -0.15. This is contradictory of my assignment submission that was a positive 0.15. Upon submission to Astromancer – I chose -0.15 as data lined up better in HR diagrams. I found I needed to take fairly aggressive cuts into Astromancer to get rid of enough field stars. Yet after this assertive style of weeding out many field stars, I still felt there was a reasonable amount of noise in the results. That being said, I did find the following:

BP v BP-RP didn’t indicate any blue stragglers along the turn off point

There appears to be many white dwarfs below the main sequence

No nebula, giants or super giants were found

The following parameters used to compare with my results were taken from the Milky Way Star Clusters Catalog (MWSC) , thanks to Kharchenko (2013)

Contrasting this data with MWSC Catalouge – there were a few things. Firstly, despite changing my final metalicity twice, the MWSC value of 0.19 was closer to my original submission of 0.15 rather than the later -0.15. Other values were closer to the catalogue, my log age 8.2 versus MWSC’s 8.18 and my E(B-V) 0.19 vs MWSC’s 0.208. Compared to my HR Diagrams, I would say my line is a better fit then MWSC’s

To the left is my HR Diagram using my parameters, and to the right are MWSC’s.

 

 

 

 

 

Here is a De-reddened image of my star cluster!

Some more important data: (Left to right:     2MASS H vs J-H   —   My H vs J-H  —  V vs B-V —

 

With all that being said, I’m thankful to have walked away from this Astronomy class with not only learning a thing or two about stars, but completing an analysis with some level of credibility. It’s been genuinely interesting (despite having to rush some aspects of this due to other classes), and I’d like to thank the TAs at the help desk who keeped me from getting lost, and our  instructor for giving us a cool project to work on and show off by the end of class. There are some aspects of this post I’d like to polish more, but overall I tried my best and feel like I learnt something.

Thanks for reading,

Ronin Bircham