Warm high velocity CO in the wind of Sakurai's Object (= V4334 Sgr)
  We present UKIRT UIST spectra of Sakurai's Object (=V4334 Sgr) showing CO fundamental band absorption features around 4.7 microns. The line-centres are at heliocentric radial velocity of -170+/-30 km/s. The number and relative strengths of the lines indicate a CO gas temperature of 400+/-100 K and CO column density of 7(+3/-2)x10^17 per square cm. The gas was moving away from the central star at an average speed of 290+/-30 km/s in 2003 September. The lines appeared sometime between mid 1999 (well after the opaque dust shell formed) and mid 2000 and may have been somewhat more blue--shifted initially than they are now. The observed CO velocity and temperature indicate the continued presence of a fast wind in the object, previously seen in the He I 1.083 micron line beginning just prior to massive dust formation, and more recently in atomic and ionized lines. The dust continuum is consistent with a temperature of 350+/-30 K, indicating continued cooling of the shell. The similar CO temperature suggests that the bulk of the CO absorption occurs just outside of the dust continuum surface. 
S. P. S. Eyres, T. R. Geballe, V. H. Tyne, A. Evans, B. Smalley, H. L.   Worters