Spectral data are presented for comets 2006 VZ13 (LINEAR), 2006 K4 (NEAT),
2006 OF2 (Broughton), 2P/Encke, and 93P/Lovas I, obtained with the Cerro-Tololo
Inter-American Observatory 1.5-m telescope in August 2007. Comet 2006 VZ13 is a
new Oort cloud comet and shows strong lines of CN (3880 angstroms), the Swan
band sequence for C_2 (4740, 5160, and 5630 angstroms), C_3 (4056 angstroms),
and other faint species. Lines are also identified in the spectra of the other
comets. Flux measurements of the CN, C_2 (Delta v = +1,0), and C_3 lines are
recorded for each comet and production rates and ratios are derived. When
considering the comets as a group, there is a correlation of C_2 and C_3
production with CN, but there is no conclusive evidence that the production
rate ratios depend on heliocentric distance. The continuum is also measured,
and the dust production and dust-to-gas ratios are calculated. There is a
general trend, for the group of comets, between the dust-to-gas ratio and
heliocentric distance, but it does not depend on dynamical age or class. Comet
2006 VZ13 is determined to be in the carbon-depleted (or Tempel 1 type) class.Comment: 8 pages, 6 figures, 6 tables; Accepted by MNRA
