M. Centurion, Instituto de Astrofisica de Canarias; P. Bonifacio, Osservatorio Astronomico di Trieste; N. Walton, Isaac Newton Group of Telescopes; and D. King, Royal Greenwich Observatory, report: "A high-resolution (about 50 000) CCD spectrum of SN 1998bu was obtained by the Extra-solar Planet Observational Research Team with the Utrecht echelle spectrograph on the 4.2-m William Herschel telescope at La Palma on May 18.61 UT. Preliminary reduction reveals two interstellar components of the Ca II doublet (K and H) from M96 at heliocentric radial velocities of +743 km/s (equivalent width of K, EW_K = 0.0107 nm), in agreement with the velocity of the stronger component of Na I also reported by Munari et al. on IAUC 6902, and +750 km/s (EW_K = 0.0060 nm), which is not observed in Na I. A weak Na I component at +722 km/s is also observed in our spectrum. Five components of Ca II originating in the galactic interstellar medium are observed at heliocentric radial velocities of -26 km/s (EW_K = 0.0077 nm), -8 km/s (EW_K = 0.0154 nm), +7 km/s (EW_K = 0.0016 nm), +48 km/s (EW_K = 0.0012 nm), and +53 km/s (EW_K = 0.0022 nm). A single component is observed in Na I at -8 km/s, in agreement with Munari et al. (op.cit.)."
International Astronomical Union Circular
- Pub Date:
- May 1998