Gaia’s billion-star map hints at treasures to come

In the article, “Gaia’s billion-star map hints at treasures to come”, posted to, relates to our 11 objective, ” I can explain how astronomers study the properties of stars including: distance, size, and mass” sufficiently. The article states that the first catalogue from the ESA’s Gaia satellite released more than a billion stars and also the brightness of 1142 million stars, and the distance and motion of more than 2 million stars. In addition to this newly catalogue, astronomers also looked into fuller detail at the 2 million stars in common between Gaia’s first year and the earlier Hipparcos and Tycho 2 catalogues to disect the effects of parallax and proper motion from the observations. Thanks to our lectures in class, we know that parallax is the apparent shifting of an object against the background, due to viewing it at different positions and proper motion is the motion of an object in the plane of the sky, perpendicular to our line of sight. With this, astronomers are able to measure the distance and motions for the 2 million stars. The article goes on to discuss how the new catalogue, Gaia, is 2x more precise and contains 20x more stars as well opposed to the previous catalogues, Hipparcos and Tycho. With the improvements of Gaia, they are now able to measure distances and motions of stars up to 400 clusters and 4800 light years away, such as many more stellar clusters that contain variable stars that swell and shrink, leading to apparent brightness changes of these stars, which we also learned in class that the apparent brightness tells us how bright an object will appear from Earth. This also is seen by the new data of Gaia that allows the astronomer to measure these variable stars brightness, which is valuable for scientists to observe deeper into faraway galaxies in the future by viewing and comparing both the parallax, brightness changes, and properties of these stars. Now specifically, this article relates to our class objective because of the new discoveries founded from the data collected from the Gaia catalogue that was based off of the precise distance of stars using the parallax, proper motion, and the brightness of these stars from its luminosity. The astronomers were able to discover and measure the Gaia stars distance to other galaxies and nearby stars by observing how its apparent location shifts as Earth orbits the Sun and can interpret the stars masses from measuring the size of these specific stars orbit, motions, and orbital periods. During our lectures in class from the lecture tutorial book, we were able to identify a stars parallax angle that allowed us to calculate the distance to the star examples as well, but keeping in mind that the nearest stars are still very far away so the parallax angles are very small too. We knew this because of the finger example we did in class, understanding that although a star may be closer opposed to a farther away star, it has a larger parallax angle. I found this article to be interesting because not only did it involve our objective of the properties of stars and how astronomers determine them, but it also shared new discoveries from the Gaia catalogue that will benefit future research.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s