We model the emission lines generated in the photoionised debris of a tidally
disrupted horizontal branch star. We find that at late times, the brightest
optical emission lines are [N II] \lambda\lambda 6548,6583 and [O III]
\lambda\lambda 4959,5007. Models of a red clump horizontal branch star
undergoing mild disruption by a massive (50 -- 100 M_\sun) black hole yield an
emission line spectrum that is in good agreement with that observed in the NGC
1399 globular cluster hosting the ultraluminous X-ray source CXOJ033831.8 -
352604. We make predictions for the UV emission line spectrum that can verify
the tidal disruption scenario and constrain the mass of the BH.Comment: 8 pages, 6 figures, Accepted for publication in MNRA
