SIMBAD references

H. Marion, University of Texas and Texas State University; P. Garnavich, University of Notre Dame; C. L. Gerardy, Florida State University; R. J. Rudy, D. K. Lynch, and R. W. Russell, Aerospace Corporation; and C. E. Woodward, University of Minnesota, observed supernova 2008ax (cf. CBET 1285) on Mar. 14.5 UT with the Infrared Telescope Facility (+ SpeX instrument in low-dispersion mode). The spectrum (wavelength range 0.7-2.4 microns) shows strong P-Cyg profiles of He I at 1.08 and 2.06 microns and Ca II at 0.85 microns. The expansion velocity of the 1.08-micron He I line is 11000 km/s. Paschen-beta is very weak, and analysis with SYNOW synthetic spectra (Branch et al. 2007, AIP Conf. Proc. 924, 342) indicates that Paschen-beta is likely contaminated by He I. The 2008ax spectrum is similar to the infrared spectrum of supernova 1999ex (Hamuy et al. 2002, A.J. 124, 417) near maximum. SN 1999ex was a type-Ib/c event, and 2008ax – with its weak hydrogen and dominant He I – appears as a type-Ib supernova in the near-infrared.