For eons humankind has looked at the stars
trying to understand our place in Universe,
wondering about distant stars and galaxies.
With current technology
we are now able to explore farther
and more detailed than ever.
With the Gaia space observatory
the European Space Agency
aims to create the most accurate and complete multi-dimensional map
of our astonomical neighbourhood,
the Milky Way.
A truly herculean and ground-breaking endeavour.
Gaia is a wonderful mission
which is intended to look at the stars,
determines their position,
motion
and the astrophysical parameters.
their ID-card in some sense
So it is a big database containing the information,
how the galaxy moves
and what the galaxy is made of.
And with the help of theoretical models,
we will be able to reconstruct the past,
the history of our galaxy
and also predict its future.
Now the mission has passed another milestone
with a third full data release
after two earlier releases in 2016
and 2018.
With each new release
the observed stars,
Solar System objects
and extragalactic objects increase
and more details are added to what is already
the most detailed overview of our galaxy.
New in this data release
are spectra for a significant number of these stars and other objects,
which can be used to accurately determine luminosity,
temperature,
mass
and chemical composition.
Another important feature in the Gaia catalogue
is the inclusion of the radial velocity for over 33 million stars,
a five-time increase compared the previous data release
and the largest radial velocity survey to date.
Radial velocity is important
as it tells us how fast stars are moving away from us
or moving towards us.
The radial velocity
is the velocity of the star along the line of sight.
While the tangential velocity
that is obtained from the astrometric measurement,
tells you how the star moves in the plane of the sky.
So the combination of the radial velocity
with the tangential velocity
provides the three dimensional information on the star velocity.
This new data release
also contains for the first time
information on multi-star systems
when two or more objects are orbiting one another.
This information was obtained by using all three observing techniques of Gaia:
astrometry,
photometry
and spectroscopy.
As a result
this Gaia data release
sees the inclusion of largest catalogue of binary stars in our galaxy.
The catalogue of these stars
is crucial for understanding stellar evolution
and this surpasses all the work that has been done on binary stars
in the last two centuries.
Binary stars are also important to determine the mass of a star
and to discover exoplanets.
In general,
you can determine the mass only when you have a binary system.
When the object is single,
you need to rely on the model for that.
When it's binary,
then you get the precise mass of the two components.
If you have enough information.
So it's a way to determine it observationally it's not a model,
it's an observation.
So it's much more precise than what you can infer from stellar physics.
With this new data release,
Gaia is once more proving its worth,
helping us to understand our galaxy,
and pointing out new areas for scientists to research.
The Gaia data is,
I would say,
a silent revolution
because now you get information about the stars,
for hundreds of millions of stars
that no one could have dreamed before.
Gaia is an example of collaboration between ESA,
European institutions
and over 400 scientists.
They will will soon already be working on the next data release
providing ever more observations and data
coming from the Gaia mission
moving in sync with our planet as it scans the heavens.