The Richest Star Catalogue Of 1.7 Billion Stars | Details Of Milky Way

  • ESA’s Gaia has released the largest catalogue of stars with much greater precision. 
  • It contains precise motion and parallax of over 1.3 billion stars, as well as properties of other celestial bodies.
  • Its data have been used to determine orbits of 12 dwarf galaxies and 75 globular clusters, revolving around the Milky Way. 

European Space Agency’s spacecraft, named Gaia, has generated richest star catalogue, which includes approximately 1.7 billion stars, revealing the unknown details of our Galaxy, Milky Way.

For those who don’t know, Gaia is the space observatory developed for measuring the exact distances and positions of stars. The ultimate goal is to create the largest and most accurate three dimensional space catalog, which not only includes stars but also planets, asteroids, comets and quasars.

The spacecraft was launched in December 2013, with a total mission cost of around $1 billion. The catalogue is released in stages that will contain increasing amounts of data. The first catalogue — containing information of 1.1 billion stars — was released in November 2016.

The new release tells the position of approximately 1.7 billion stars with much greater precision. How accurate are these measurements, you asked? Well, for a few bright stars, the accuracy level equates to observers on Earth being able to spot a penny lying on the Moon’s surface.

What Data Gaia Collected?

This level of accuracy made it possible to differentiate the star’s parallax (apparent shift on the sky caused by one year Earth-orbit around the Sun) from its actual motion through the galaxy.

This catalogue list the precise motion and parallax of over 1.3 billion stars as well as properties of other celestial bodies. It is now possible to directly calculate distances to most of the stars. Also, the data will help astronomers distinguish between several stars of different ages scattered throughout the Milky Way.

Gaia’s sky in color |  Credit: ESA

The spacecraft collected brightness information and color measurements of stars, as well as how the color and brightness varies over time. It also tells about the impact of interstellar dust on 87 million stars and surface temperature of 100 million stars.

Reference: Astronomy & Astrophysics | ESA

The catalogue contains position and orbit of over 14,000 asteroids in our solar system. Moreover, it points out the location of nearly 500,000 quasars and bright galaxies.

Cosmic scale covered by Gaia | Credit: ESA 

The information is helpful for determining a reference frame for the celestial coordinates of all bodies identified by Gaia. So far, this has been done using radio waves. And now, for the first time, it’s accessible via optical wavelengths.

3D View Of Galaxy

The spacecraft has measured stars’ velocity (in all three dimensions) that lie within a few thousand light years from the Sun, revealing their patterns of motions.

It also allows us to observe the stars’ motions within globular clusters (old star systems located in the halo of the Milky Way) and within other galaxies like Large and Small Magellanic Clouds.

The data provided by Gaia have been used to determine orbits of 12 dwarf galaxies and 75 globular clusters, revolving around our galaxy. This helps us study the distribution of mysterious dark matter, active gravitational forces, and past evolution of the Milky Way.

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What’s Next?

The 3rd catalogue will consist of orbital solutions for several binary stars and objects, as well as improved parallaxes, positions and motions. The 4th one will include non single-star catalogues, whole Solar System results and variable star classifications. The final catalogue will be released in 2022, with more precise data that will show us some more secrets of our galaxy.

Written by
Varun Kumar

Varun Kumar is an experienced science and technology journalist interested in machines, AI, and space exploration. He received a Master's degree in computer science from Indraprastha University. To find out what his latest project is, feel free to directly email him at [email protected] 

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