In the Milky Way, 3 intruder stars are 'on the run' — in the wrong direction

[Admin]

Three ancient stars that hail from cannibalized dwarf galaxies are "on the run" at hundreds of thousands of miles per hour in the Milky Way's galactic halo.

In the Milky Way, 3 intruder stars are 'on the run' — in the wrong direction : Read more

 

[Unclear Engineer]

The first question that comes to me about this article has to do with the orbital speed and direction. How does it compare to the speeds of other stars that rotate in the "normal direction" at about the same distance from the center of our galaxy? Can we tell if these orbits are approximately circular or highly elliptical?

 

[arturo.v.dominguez@gmail.]

We have what we call rogue planets, and what we call rogue comets. Each with its own peculiar characteristic for having been assigned that adjective. Perhaps now we a captive rogue star. I say perhaps because I have to assume that it is way too early to tell that they have indeed been captured by our Milky way.

 

[mcswell]

I think we should call them Oley Stars. Why, you ask? I'm glad you asked!

Oley was driving home from work one night, when his wife Lena called him on his cell phone. "Oley, you be careful out there!" she said. "The radio, they say someone is driving the wrong vay on de freevay."

Oley answered, "Yah, sure, if dere's one dere's a tousand."

 

[arturo.v.dominguez@gmail.]

In this trio of stars, I conclude that one of them, Oley, is in the driver's seat. So does that make the other two companions, abductees; or maybe even a mini posse out to try and corral the escapee.

 

[Torbjorn Larsson]

A SASSy find, no doubt.

The first question that comes to me about this article has to do with the orbital speed and direction. How does it compare to the speeds of other stars that rotate in the "normal direction" at about the same distance from the center of our galaxy? Can we tell if these orbits are approximately circular or highly elliptical?

The paper show kinematic simulations of the 3 initial SASS stars based on their current orbital parameters. Their orbits vary from circular to highly elliptical.

In general the disk stars form from cold gas clouds which by their nature of being cooled has assembled in the gravitational well midplane of the halo. Such stars tend to have similarly kinetically calm circular orbits. Halo stars are captured from exogalaxies during Milky Way merger assembly, or ejected from multistellar systems/supernovas/galaxy core, and they will tend to have elliptical orbits and for exocaptures about half will be retrograde.