Gaia DR2 made available, 1.7 billion stars measured

[Zandvliet]

Sources:

• https://www.cosmos.esa.int/web/gaia/home
• https://www.cosmos.esa.int/web/gaia/image-of-the-week
• https://www.cosmos.esa.int/web/gaia/dr2

Another great overview of all the data plus addition links:

• https://gea.esac.esa.int/archive/documentation/GDR2/index.html

 

The Gaia satellite- credits: ESA, ATG medialab

 

The Gaia satellite, which launched on December 19th 2013, has just released its second data set (DR2) containing statistics of just under 1.7 billion stars! This is a great moment for the astronomical community who now has the opportunity to feast on a lot of data. And the best part is: you can download all the data yourself! See: https://gea.esac.esa.int/archive/ 

 

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Gaia is an ambitious mission to chart a three-dimensional map of our Galaxy, the Milky Way, in the process revealing the composition, formation and evolution of the Galaxy. Gaia will provide unprecedented positional and radial velocity measurements with the accuracies needed to produce a stereoscopic and kinematic census of about one billion stars in our Galaxy and throughout the Local Group. This amounts to about 1 per cent of the Galactic stellar population. 

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On 14 April 2018, about 10 days before the second Gaia Data Release, the spacecraft and daily data processing systems have reached yet another stunning milestone: the number of star transits has reached 100 billion!

Gaia has been measuring star transits almost continually since 2013 completing a full sky survey every 2 months and then stars over, detecting circa 100000 stars per minute (source: live coverage of the release). Which is not just a crazy amount of data points but also a hugh technical achievement. Thus resulting into the total number of star transits of 100 billion. Note that the data set of Gaia does not contain 100 billion stars, but 1692919135 stars, where the stars are measured multiple times during the course of the observations. Which is only about 1 percent of the total number of stars in our galaxy alone. And our galaxy is only one galaxy in the universe, which is estimated (as far as we know now) to have 2 trillion galaxies. 

 

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Below an overview of the planned Gaia Data Release 2 in numbers:

 

# sources in Gaia DR2 # sources in Gaia DR1 Total number of sources 1,692,919,135 1,142,679,769 Number of 5-parameter sources 1,331,909,727 2,057,050 Number of 2-parameter sources 361,009,408 1,140,622,719 Sources with mean G magnitude 1,692,919,135 1,142,679,769 Sources with mean GBP-band photometry 1,381,964,755 - Sources with mean GRP-band photometry 1,383,551,713 - Sources with radial velocities 7,224,631 - Variable sources 550,737 3,194 Known asteroids with epoch data 14,099 - Gaia-CRF sources 556,869 2,191 Effective temperatures (Teff) 161,497,595 - Extinction (AG) and reddening (E(GBP-GRP)) 87,733,672 - Sources with radius and luminosity 76,956,778 -

Besides the fact that there are many sources measured, another great accomplishment is the fact that there are over 7 million sources with radial velocities. This means that of over 7 million stars we know how fast they are moving through the Milky Way and in which direction. This can result in a much greater understanding of galaxy dynamics. Also pay attention to the difference in sources for the variable sources in DR1 and DR2 (these are stars whos magnitude\brightness changes over time periodically). These sources are also called 'standard candles', this is because they have a very well defined relation between variability and brightness. And in the world of astrophyics knowing the brightness of a source very accurately is knowing the distance very well. Hence the name 'standard candle'. 

 

Image source: https://www.esa.int/spaceinimages/Missions/Gaia

 

To end this post I'd like to show the images made from the data in DR1(left) and DR2 (right), I highly recommend downloading the images yourselfs and take a look at our Milky Way and many other sources inside the Milky Way. 

 

Any more astronomers on this forum? What do you guys think about this release? I think this release is another monumental accomplishment and in the coming years astronomers will have their hands full understanding the data and revealing more mysteries of our Milky Way/universe.

 

Quick side note: most people often ask me what is the point of astronomy, but most people do not know how many technical inventions orgininate from astronomy/space travel. Like velcro, high res camera's, MRI technology etc etc. on top of the scientific understanding of our universe.

 

 

Edited April 25, 2018 by Zandvliet

[Serin]

Wanted to say something more clever than 'ahhhh! excited by mapping the stars!'
But really that's all that is needed.

Always thought it be ridiculously fun(and equally difficult) to import Gaia's data into a cg program as a particle system or something. Just kinda zoom around an actual star map in 3d.

[Zandvliet]

9 minutes ago, Serin said:

Wanted to say something more clever than 'ahhhh! excited by mapping the stars!'
But really that's all that is needed.

Always thought it be ridiculously fun(and equally difficult) to import Gaia's data into a cg program as a particle system or something. Just kinda zoom around an actual star map in 3d.

Hehe.

 

They did show some videos where they could move around a section of the Milky Way. It shouldn't be that hard (code wise) as you know the positions in space and their relative velocity and direction. However the computational power is another story  

This link does sometime similar and cool, but for only 100000 stars.

[Serin]

42 minutes ago, Zandvliet said:

Hehe.

 

They did show some videos where they could move around a section of the Milky Way. It shouldn't be that hard (code wise) as you know the positions in space and their relative velocity and direction. However the computational power is another story  

This link does sometime similar and cool, but for only 100000 stars.

Uhhhhhhhhhh that link is awesome thank you!
And yeah, it'd just be computationally painful. At least in realtime. 

[Nicnac]

1 minute ago, Serin said:

Uhhhhhhhhhh that link is awesome thank you!
And yeah, it'd just be computationally painful. At least in realtime. 

Now someone build this in Universe Sandbox lol ^^

[Zandvliet]

1 hour ago, Serin said:

Uhhhhhhhhhh that link is awesome thank you!
And yeah, it'd just be computationally painful. At least in realtime. 

No problem!

[tikker]

3 hours ago, Serin said:

Wanted to say something more clever than 'ahhhh! excited by mapping the stars!'
But really that's all that is needed.

Always thought it be ridiculously fun(and equally difficult) to import Gaia's data into a cg program as a particle system or something. Just kinda zoom around an actual star map in 3d.

It's actively being worked on to optmize these kinds of visualizations: https://vaex.io/