Starship Asterisk*

by Asa Stahl

The catalog includes asteroids, galaxies, and the stuff between the stars.

Link: Science News

Gaia Data Release 3
ESA | Science & Technology | Gaia | 2022 Jun 13

Gaia Sees Strange Stars in Most
Detailed Milky Way Survey to Date
ESA | Science & Technology | Gaia | 2022 Jun 13

Today, ESA’s Gaia mission releases its new treasure trove of data about our home galaxy. Astronomers describe strange ‘starquakes’, stellar DNA, asymmetric motions and other fascinating insights in this most detailed Milky Way survey to date.

Gaia is ESA’s mission to create the most accurate and complete multi-dimensional map of the Milky Way. This allows astronomers to reconstruct our home galaxy’s structure and past evolution over billions of years, and to better understand the lifecycle of stars and our place in the Universe.

Gaia’s data release 3 contains new and improved details for almost two billion stars in our galaxy. The catalogue includes new information including chemical compositions, stellar temperatures, colours, masses, ages, and the speed at which stars move towards or away from us (radial velocity). Much of this information was revealed by the newly released spectroscopy data, a technique in which the starlight is split into its constituent colours (like a rainbow). The data also includes special subsets of stars, like those that change brightness over time.

Also new in this data set is the largest catalogue yet of binary stars, thousands of Solar System objects such as asteroids and moons of planets, and millions of galaxies and quasars outside the Milky Way.

1. Radial velocity
2. Radial velocity and proper motion
3. Interstellar dust
4. Chemical map

I am not happy with the posted infographics.
White lines trace the tangential movement of 26 million stars in the nearest part of the galaxy, that's ok.
Background fill colors should show the radial velocities of that stars, should they not?
So off with the Large and Small Magellanic Clouds and field globular clusters, that's ok.
But why leave the two spots that white lines have to cross near the center of the map and that are supposed to correlate with the Milky Way's bar?
All those two spots do is messing with the map of the stellar flows.

Now what did I expect before I get to see this map?
Some stars must follow some path passing by Sun; half of the path would be with radial velocity component of coming closer towards Sun and the other half of the path would be populated with red-shifted stars.
Particularly, a lower galaxy orbit would make a path of stars orbiting a little faster than Sun (though the dark matter halo make Sun's galactic orbital velocity almost equal to a lower orbit's one). A higher orbit makes for a path in the other direction. Sun's bias toward the Northern surface of the galactic disk should make the two flows look a little lower than the galactic equator; each flow should span almost 180° horizontally.

I don't think this is what I see. I can see a 180° flow crossing the galactic center in the background; that should be the lower orbit flow.
If it orbits at a higher velocity than Sun, then the galactic core is paradoxially doing the opposite thing: spinning slower than Sun.
As for the higher orbit's flow the map is quite unfriendly and I just can't see any heads or tails.

VictorBorun wrote: ↑Wed Jul 06, 2022 10:26 am As for the higher orbit's flow the map is quite unfriendly and I just can't see any heads or tails.

Just how unfriendly a 360° map can be is illustrated here