HST spectrum and timing of the ultra-compact X-ray binary candidate 47 Tuc X9

V. Tudor, J. C. A. Miller-Jones, C. Knigge +17

To confirm the nature of the donor star in the ultra-compact X-ray binary candidate 47 Tuc X9, we obtained optical spectra (3,000$-$10,000 Å) with the Hubble Space Telescope / Spac…