New and unpublished photometric data of HD 45677 in the Walraven WULBV, Strömgren uvby, Johnson/Cousins and ESO JHKLM system are listed in an accompanying paper (de Winter et al. 1996; Paper I) and will be analyzed and discussed in this paper.
Several new low resolution CCD spectra of HD 45677 were taken at La Silla using the Boller and Chivens spectrograph mounted on the ESO 1.52 m telescope. Details of the observations are given in Table 1 (click here). In order to get a sufficiently good S/N for weaker emission lines it was necessary to have the strength of H exceed the CCD saturation limit. To be able to measure the relative strength of H second, shorter, exposures during the same two December nights were taken in which H was not saturated. A combined spectrum of the 1992 d, e, f and 1992 g spectra is presented in Fig. 4 (click here).
Table 1: Log of published and newly taken optical
spectroscopic observations of HD 45677
To reveal the H profile and to test for short time scale variations two intermediate resolution spectra, Fig. 5 (click here), centered around H, were obtained. These observations, see Table 1 (click here), were made with the Boller and Chivens spectrograph mounted on the ESO 1.52 m telescope at La Silla. The detector for all the low and intermediate resolutions taken spectra was a Ford Aerospace 20482048 pixel CCD, with a 1515 m pixel size.
To detect short time scale variations, HD 45677 was followed day to day between the 8 and the 14 of October 1993 by using the CAT/CES combination at La Silla. This combination was used to obtain high resolution spectra in the H and NaID wavelength ranges, which are presented in Figs. 9 and 10. Further high resolution spectra, in the H, CaIIK, and [OI] 6300 Å wavelength ranges (Figs. 6-8), were obtained in January 1994. During all observations, the detector was a 1024 640 RCA SID 006 high resolution CCD, with a pixel size of 1515 m. All the CAT/CES observations were controlled remotely from ESO Headquarters, Garching bei München, Germany.
All spectra were reduced using the MIDAS software running under SUN/OS at ESO headquarters. For optimal extraction of spectral data from the CCD images the optimal extraction algorithm by Horne (1986) was applied. After reduction, the low-resolution spectra were combined into one single, completely unsaturated, spectrum, with spectrophotometric quality. The new spectral data are shown in Figs. 4-10. Additional details of all spectroscopic observations are listed in Table 1 (click here).
Images of HD 45677 were obtained, under reasonable (1 1-1 6) seeing conditions, with the Dutch 92 cm telescope at La Silla. Two observing runs were used, on the 10 and 14 of February 1993, and on the 7 of August 1993. The images were reduced using MIDAS, running on a VAX cluster at the University of Amsterdam. On all of the images, taken through B, V, R, Gunn i, Gunn z, wideband H, narrowband H and narrowband [OI]6300 filters, HD 45677 was indistinguishable from a stellar point source. No nebulosity of emission or reflection nature were visible. By checking POSS (Palomar Observatory Sky Survey) plates, searching for significant changes of the number of stellar objects in the surroundings of HD 45677, no dark region could be marked.
Figure 1: Light curve of HD 45677. a) Using photographic and photoelectric data from 1899 to 1994. b) Using photoelectric data from 1971 to 1994. The labels A - E denote the different datasets discussed in Sects. 3.2 and 3.3