The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy’s Central Black Hole: A Paradox of Youth

  title={The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy’s Central Black Hole: A Paradox of Youth},
  author={Andrea M. Ghez and Gaspard Duch{\^e}ne and Keith Y. Matthews and Seth D. Hornstein and Angelle M. Tanner and James E. Larkin and Mark R. Morris and Eric Edward Becklin and Samir Salim and Ted Kremenek and D. J. Thompson and Baruch T. Soifer and Gerry X. Neugebauer and Ian S. McLean},
  journal={The Astrophysical Journal Letters},
  pages={L127 - L131}
We have obtained the first detection of spectral absorption lines in one of the high-velocity stars in the vicinity of the Galaxy's central supermassive black hole. Both Brγ (2.1661 μm) and He I (2.1126 μm) are seen in absorption in S0-2 with equivalent widths (2.8 ± 0.3 and 1.7 ± 0.4 Å) and an inferred stellar rotational velocity (220 ± 40 km s-1) that are consistent with that of an O8-B0 dwarf, which suggests that it is a massive (~15 M☉) young (less than 10 Myr) main-sequence star. This… 

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