Introduction
NGC 3532 also known as The Wishing Well Cluster is an intermediate age cluster located in the southern constellation of Carina. Because it has an apparent magnitude of 3 which is the best target for the just small telescope to view in the southern sky from earth. However, it is not visible for Saskatoon because it lies too far south that it will not rise above the horizon.
History
The star cluster NGC 3532 was first discovered by French astronomer Nicolas Louis de Lacaille. By observing from South Africa during 1725 and cataloged in 1755, he managed to discover a cluster consisting of about 150 stars. NGC 3532 covers an area of the sky from our perspective that is about twice the size of the full moon. From John Herschel’s observation, he described the star clusters involved with mostly binary star systems. Another fun fact about NGC 3532, it was the first target that NASA/ESA Hubble Space Telescope observed during 20 May 1990.
In a recent study about the star cluster in 2022 January 3rd, there exists two eclipsing binary stars in the open cluster. Based on their light-curve analyses, HD 96609 and HD 303734 were identified as detached eclipsing binaries. HD 96609 is composed of two main sequence stars, their log mass/log radius suggest that their log(age/yr) is about 8.55 which is in range of the log age of the star cluster NGC 3532 analyzed in the earlier studies. On the other hand, HD 303734 is an eclipsing binary with a shallow secondary eclipse. By using the photometric properties of the system, they have found HD 303734 consists of A6V + K3V components. These two-star systems were the second and third eclipsing binaries discovered in the region of NGC 3532.
In order to study the NGC 3532, I used multiple online platforms such as Skynet and after glow. First, I collected images through Skynet using Prompt5 telescope in different filters such as blue, green and red color filters with the total exposure durations of 40, 40, 25s. These images are then used for studying the colors, brightness, age and metallicity relations of the star cluster. Second, I used Afterglow to stack the taken images and find the photometry of all the visible stars in the image to then extract data and plot them. I also used Gaia data to find the parameters for each of the stars in the star cluster. Here’s the analyzed data from the plotting:
MSI-Reddened image of NGC 3532
Dereddened image of NGC 3532
Discussion:
By observing my results, there’s less stars than what the star cluster should have. I would assume the star cluster was very hard to analyze because of the small number of stars in the system. It could also be due to the incorrect selection of Dec, RA and the distance. From the plotting, we can see there exist about 6 red giants and 5 white dwarves in the system which it was how Wikipedia described about the cluster. One interesting fact about the cluster during the analysis of the star cluster motions in RA and Dec from the Gaia data is that I discovered a secondary cluster migrating towards NGC 3532.
RA: -6.15 +- 1 mas/yr
Dec: 2.19+- .7 mas/yr
Distance: 3.49 kpc +- 20%
number of stars: 52
log(Age): 9.02 log(yr)
Metallicity: -0.22 solar
E(B-V): 0.11 mag
Conclusion:
The cluster project is the most challenging project for me, there were major issues of Afterglow crashing and I always felt like I have made mistakes here and there, by comparing my data from the data provide by Milky Way Star Clusters Catalog, I see many problems in my data such as the distance and extinction value. However, by plotting the data from MWSC on the website, the diagram looks completely wrong from the stars. I would assume it might be due to the incorrect choice of the motions in RA and Dec. In the end, I managed to complete the project with really poor results.
Reference:
SIMBAD references (unistra.fr) 2022/January-2
The Wishing Well cluster is well placed – In-The-Sky.org
Wishing Well Cluster (NGC 3532) – Constellation Guide (constellation-guide.com) March 5, 2023
A Colourful Gathering of Middle-aged Stars | ESO 26 November 2014, European Southern Observatory