Monday, May 24, 2021

Lets talk about the Pleiades

The Pleiades (also known as the Seven Sisters and Messier 45) is an open star cluster located at a distance of 445 light years in the constellation of Taurus. Together with their sister star cluster the Hyades, form the Golden Gate of the Ecliptic.

The cluster is visible to the naked eye and it is dominated by middle-aged hot B-type stars. Evolutionary simulations of the cluster suggest that the Pleiades were formed as a compact cluster. Estimates indicated that the cluster will be “alive” for another 250 million years, and eventually disperse in the local vicinity.

The brightest stars are named after the Seven Sisters of Greek mythology, Asterope, Merope, Helectra, Maia, Taygeta, Celaeno, and Alcyone. The other two are their father Atlas and their mother Pleione.

The core radius is around 8 light years, while its tidal is around 43 light years. There are over 1,000 members in the cluster. Many brown dwarfs have been discovered in the region and they contribute 25% in terms of population, but less than 2% of the mass.

Finally, reflection nebulosity is present around the bright stars, due to leftover material. This can be observed with a pair of binoculars, or a small telescope.

Fun facts: 

1. The famous Japanese automobile manufacturer Subaru, is named after the Seven Sisters (six in Japanese mythology) and it is the logo of the company.  

2. The 8.2-metre telescope Japanese telescope in Mauna Kea, Hawaii, is also named after the famous cluster (Subaru).

Image 1: Composite optical image of the Seven Sisters taken with a small telescope. The image was created using broadband filters (R-band, G-band, and R-band).




Image 2: An annotated image of the Seven Sisters. The image comes from Digitized Sky Survey and it was created using broadband filters (B-band, R-band, I-band).

Image 1 Credit: Naele Walters

Image 2 Credit: NASA/ ESA/AURA/Caltech

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