Astronomers identify 25 stars that have or will come within 3 light years of Sun
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Using the second data release from Gaia, astronomers have identified 25 stars that have or will come within 3 light years of Sun sometime within fifteen million years.
But the authors are confident that the 25 stars represent only a sliver of the actual encounters that have occurred over this time period. “They’re still just scratching the surface,” Mamajek agrees. That’s because the Gaia satellite eliminates low-mass stars (which are simply too faint to see at the moment) and high-mass stars (which are often so bright they saturate the satellite’s detectors) — thus limiting the data to stars that range between 0.5 and 1.3 times the mass of the Sun.
As such, the team suspects that they have only spotted 15% of all the encounters that likely pummel our solar system. “It’s a good first step, but one should not look at this as the final word,” Mamajek adds.
In reading their paper (available here), they identify three stars come come within a light year, therefore disturbing the theorized Oort Cloud of comets thought to exist at this distance from the Sun. One, Gliese 710, will do so in 1.3 million years..
It is now the third week in my annual anniversary fund-raising campaign for Behind the Black.
Please consider donating. I am trying to avoid advertising on this website, but will be forced to add it if I do not get enough support from my readers. You can give a one-time contribution, from $5 to $100, or a regular subscription for as little as $2 per month. Your support will be deeply appreciated, and will allow me to continue to report on science and culture freely.
Regular readers can support Behind The Black with a contribution via paypal:
If Paypal doesn't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
Using the second data release from Gaia, astronomers have identified 25 stars that have or will come within 3 light years of Sun sometime within fifteen million years.
But the authors are confident that the 25 stars represent only a sliver of the actual encounters that have occurred over this time period. “They’re still just scratching the surface,” Mamajek agrees. That’s because the Gaia satellite eliminates low-mass stars (which are simply too faint to see at the moment) and high-mass stars (which are often so bright they saturate the satellite’s detectors) — thus limiting the data to stars that range between 0.5 and 1.3 times the mass of the Sun.
As such, the team suspects that they have only spotted 15% of all the encounters that likely pummel our solar system. “It’s a good first step, but one should not look at this as the final word,” Mamajek adds.
In reading their paper (available here), they identify three stars come come within a light year, therefore disturbing the theorized Oort Cloud of comets thought to exist at this distance from the Sun. One, Gliese 710, will do so in 1.3 million years..
On the topic of astronomy, I’m also hearing reports that scientists now believe the Milky Way might be 200,000 light years in diameter, vs 100,000 or 150,000 light years…
Thought you might be interested: https://www.nbcnews.com/mach/science/milky-way-galaxy-may-be-much-bigger-we-thought-ncna876966
Have they considered running the calculation backwards? I.e. Are there suns that have done this in the past? Do those coincide with other events in the historical record? That seems like it would be interesting.
geoffc: Read the paper. From what I can determine, they have done their calculations in both directions, both into the future as well as the past.