In this paper , we investigate the link between the hypervelocity stars ( HVSs ) discovered in the Galactic halo and the Galactic center ( GC ) S-stars , under the hypothesis that they are both the products of the tidal breakup of the same population of stellar binaries by the central massive black hole ( MBH ) .
By adopting several hypothetical models for binaries to be injected into the vicinity of the MBH and doing numerical simulations , we realize the tidal breakup processes of the binaries and their follow-up dynamical evolution .
We find that many statistical properties of the detected HVSs and GC S-stars could be reproduced under some binary injecting models , and their number ratio can be reproduced if the stellar initial mass function is top-heavy ( e.g. , with slope \sim - 1.6 ) .
The total number of the captured companions is \sim 50 that have masses in the range \sim 3 – 7 M _ { \odot } and semimajor axes { { { { \mathrel { \mathchoice { \lower 4.0 pt \vbox { \halign { \cr } $ \displaystyle \hfil < $ \cr$% \displaystyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \textstyle \hfil < $ \cr% $ \textstyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \scriptstyle \hfil < $ \cr% $ \scriptstyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \scriptscriptstyle% \hfil < $ \cr$ \scriptscriptstyle \hfil \sim$ } } } } 4000 { AU } and survive to the present within their main-sequence lifetime .
The innermost one is expected to have a semimajor axis \sim 300 – 1500 { AU } and a pericenter distance \sim 10 – 200 { AU } , with a significant probability of being closer to the MBH than S2 .
Future detection of such a closer star would offer an important test to general relativity .
The majority of the surviving ejected companions of the GC S-stars are expected to be located at Galactocentric distances { { { { \mathrel { \mathchoice { \lower 4.0 pt \vbox { \halign { \cr } $ \displaystyle \hfil < $ \cr$% \displaystyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \textstyle \hfil < $ \cr% $ \textstyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \scriptstyle \hfil < $ \cr% $ \scriptstyle \hfil \sim$ } } } { \lower 4.0 pt \vbox { \halign { \cr } $ \scriptscriptstyle% \hfil < $ \cr$ \scriptscriptstyle \hfil \sim$ } } } } 20 ~ { } kpc , and have heliocentric radial velocities \sim - 500 – 1500 { km s ^ { -1 } } and proper motions up to \sim 5 – 20 { mas yr ^ { -1 } } .
Future detection of these HVSs may provide evidence for the tidal breakup formation mechanism of the GC S-stars .