A team of astronomers led by John Bochanski has find the uttermost whiz in our galaxy in the mystical Milky Way halo , a rare find that may change our agreement of the formation of our astronomic rest home . They ’re so far away that , if you postulate a photo of the Milky Way from their compass , it would look like the image above .
Compare that to this photo of the Milky Way , taken from ground :
The reason for this view modification is the incredible aloofness at which these scarlet giant stars are located : ULAS J0744 + 25 is 775,000 lightsome years away while ULAS J0015 + 01 is 900,000 light years by from us . For comparison , the Milky Way ’s spiral is just 100,000 wakeful years in diam . These stars are so far off that they are even beyond the Large Magellanic Cloud , one of our near galactic neighbor . Five times far off , in fact .
If they are so far away , how is it possible that these stars are considered part of our galaxy ? I necessitate Bochanski about it :
We can cipher the length to these stars , and have measured their velocities . We can liken that to the dodging speed of the entire Galaxy , which is something we did in the paper . The velocities of these stars are less than the escape velocity , so we know they are both associated with the Galaxy . They are both moving out from the Galactic pith too , which might mean that they primitively formed in the disk of the Milky Way and were kvetch out , but this is improbable . Our best guess is that they have been stripped off a long ago accreted dwarf galaxy that the Milky Way has cannibalize .
ULAS J0015 + 01 at the center of the photo .
ULAS J0744 + 25 at the sum .
The Milky Way halo is still a big mystery to us . Our current observations are very limited — these removed adept are so faint that they are highly hard to match . When you attend at those Hubble simulacrum , what you are see is nearby milklike Way object and galax far away , not passing upstage stars .
The fact is that we do n’t know much about the immediate space that besiege the outer flange of our galaxy , with only seven star detected beyond the 400,000 - lite - year frontier . These finding are a rarified occurrence . So rare in fact that , if confirmed , they will make us re - think our current models of the formation of the galaxy .
We designed our project in a elbow room that if the giant stars were at these large distances , we ’d find them . The good good example that we have of the Milky Way ’s anchor ring predict a miniscule amount of star at these distances , but not zero . So we set off be intimate that either : 1 ) the models were right and we ’d have to get really prosperous or 2 ) the models might be incorrect and there are more stars out there . We do n’t know what case we are in just yet , but find two at these distances stand for that we ’ve either been really , really lucky , or that the exemplar may need some tweaking .
We lead off off with about 400 candidate stars , and only anticipate about 70 bona - fide colossus . If at the ending of the study we find a circumstances more of these stars , then we will have emphatically yield the modelers a mass to chew on .
Bochanski say me that now they think they will regain more :
Our initial candidate sampling had about 400 stars , and we ’ve closely observed about 40 , and found these two , along with about eight more at closer distances . At the minute I am only look at a fistful of the fairly bright stars . With a larger scope , I can probably force out our distance demarcation to at least 400 kiloparsecs ( or just about 1.3 million weak years ) , which would be really cool , since not much is wait beyond 300 kiloparsecs .
I care the fact that each of these discoveries make us recognize how small we jazz about our Universe and how much is yet to chance upon .
Milky Waystars
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