Ed, here are a couple of studies which are relevant:
On the ejection of Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015
K.E. Yeager (a1),
J. Eberle (a1) and
M. Cuntz (a1)
https://www.bing.com/search?q=On+th...B43D69A64C8AB6&ts=1601719996685&wsso=Moderate
We provide a detailed statistical study of the ejection of fictitious Earth-mass planets from the habitable zones of the solar twins HD 20782 and HD 188015. These systems possess a giant planet that crosses into the stellar habitable zone, thus effectively thwarting the possibility of habitable terrestrial planets. In the case of HD 188015, the orbit of the giant planet is essentially circular, whereas in the case of HD 20782, it is extremely elliptical. As starting positions for the giant planets, we consider both the apogee and perigee positions, whereas the starting positions of the Earth-mass planets are widely varied. For the giant planets, we consider models based on their minimum masses as well as models where the masses are increased by 30%. Our simulations indicate a large range of statistical properties concerning the ejection of the Earth-mass planets from the stellar habitable zones.
Massive star ejected from the Milky Way galaxy: 'A visitor from a strange land'
https://www.foxnews.com/science/star-ejected-from-milky-way-galaxy
Approximately 5 million years ago, a star got too close to the
"mind-boggling" black hole at the center of the Milky Way galaxy and was "ejected," a new study has found.
The star, known as S5-HVS1, ventured too close to the black hole and when it did, it was hurtled "at the blistering speed of 6 million kilometers per hour." When astronomers discovered it, it was found to be moving "nearly 10 times faster than most of the stars in the galaxy."
Cat