============================================================================ COMPOSITE OF OBSERVED SPECTRA OF ALPHA CETI Assembled 03-26-96. Alp Cet photometry file: photometry actually used to construct the spectrum. Name FWHM Mag. +/-Unc. Eff Wvl Eff Wvl F-lam Reference (Vega) (star) W/cm2/um (um) (um) (um) TCS-H 0.2600 -1.50 0.015 1.636 1.646 4.53E-13 Alonso et al. 1994 Kn 0.0488 -1.76 0.01 2.208 2.205 1.99E-13 Selby et al. 1988 Ln 0.1443 -1.91 0.02 3.782 3.763 3.00E-14 Selby et al. 1988 M 0.5418 -1.55 0.025 4.748 4.766 8.85E-15 Thomas et al. 1973 Spectral fragments and portions of these actually used in observed spectrum ("used" may include combination with other data where overlaps occur). *** N.B. The SEW data for alp Cet have an unobserved region from 2.42--2.90 um. We substituted this portion from the SEW spectrum for bet And which locally matches that of alp Cet very well. *** Fragment Reference Total range Start and stop Average resolving (um) wavelengths (um) power NIR 1 1.26- 5.46 1.26- 5.46 50 KAO 2a 3.93- 5.26 3.93- 5.04 50 KAO 2b 5.20- 7.90 5.20- 7.90 50 KAO 2c 7.66-10.31 7.66-10.20 50 KAO 3 5.31- 7.83 5.31- 7.83 150 813 4 7.53-13.21 7.53-13.09 55 LRS 5 7.67-22.74 7.67-13.49 30 LONG 6 15.60-23.42 15.97-23.28 78 LONG 7 1.25-35.00 11.18-35.00 -- References: 1. Strecker, Erickson & Witteborn 1979, Ap.J. Suppl., 41, 501, for alp Cet, with 2.42--2.90 um from bet And. 2a,b,c. FOGS data of October 24, 1988 KAO flight in New Zealand [alp Cet/alp CMa]. 3. FOGS data of November 2, 1988 KAO flight in New Zealand [alp Cet/alp CMa] taken in 5 overlapping fragments: 5.21--6.27, 6.17--7.15, 6.22--7.20, 6.24--7.21, and 6.94--7.83 um. Fragments 2a,b,c,3 were combined into a single spectrum by successive splices and combinations, augmenting the errors appropriately with each process. 4. CGS3 10 um UKIRT Archive data of November 3, 1993 [alp Cet/bet And]. 5. LRSVAX version of Groningen database at NASA-Ames; spliced and recalibrated. 6. CGS3 20 um UKIRT Archive data of November 3, 1993 [alp Cet/alp CMa]. 7. Engelke Fn. used for T=3745K and an angular diameter of 12.643 milliarcsec [mas] (Blackwell, Lynas-Gray & Petford 1991); we found the best fitting ang. diam. to be 12.655 mas. This Engelke Function was locked to the spliced combination of 8-13 and the LRS between 11.18 and 13.42 um, by splicing longward of the SiO fundamental. We used it to replace very noisy LRS observations beyond 13.42 um, and the CGS3 20 um fragment in its entirety, with an estimated uncertainty in EFn. of 2.8%, allowing for the change in shape of the EFn. for a temperature uncertainty of +/-100K. Note that although we replaced the CGS3 LONG fragment by the EFn., this observed 20-um spectrum matches the EFn. very well, in both level and mean shape (see below, and text). INFORMATION ON SPLICES AND BIASES INCURRED Process Factor determined +/-Bias% NIR cf. photometry 0.985 0.85 KAO splice to NIR 0.983 0.20 813 splice to KAO 0.995 0.20 LRS blue/red bias ..... 0.11 LRS splice to 813 0.958 0.13 Engelke Fn. splice to combined 813/LRS 1.020 0.27 LONG CGS3 20 um fragment compared with scaled EFn. 1.005 0.60 ============================================================================ Notes: 1. Composite spectra are NOT tabulated at equal intervals of the wavelength, but rather at the wavelengths of the original model. 2. In most cases "total uncertainty" is the error term most appropriate to use. It is the standard deviation of the spectral irradiance and includes the local and global biases. Local and global biases are given as a percent of the irradiance. The global bias does not contribute error to flux ratios or color measurements, and may, in those cases, be removed (in the RSS sense) from the total error. ============================================================================