Leo Houziaux

Observations spectroscopiques de HD 50138

Observations of the Be star HD 50138 have been extended to the photographic infrared region up to 9500 Å. The main features noted in this wavelength range are strong lines of Oi (8446 Å), Hi (from P 9 to P 20), the Caii infrared triplet and the λ8629 line attributed to Ni. The λ7772 multiplet of Oi is shown to undergo important changes during the period of observations (1959–1971). Higher Balmer lines do not exhibit any emission component, but their profiles are variable and indicate the presence of satellite absorption, as already mentioned by some authors.

Nova Delphini 1967. Observations du spectre nebulaire entre 5600 et 8800 Å en 1970

Five 230 Å/mm infrared spectra of Nova Delphini 1967 have been obtained from May to September 1970 on Kodak hypersensitized IN plates. Visual brightness has dropped by one magnitude between fall 1969 and fall 1970. The continuous spectrum remains strong and a mean value of 2.35 is found for the gradient in the region 6000–8000 Å, indicating a slight increase in temperature since 1969. Permitted lines ofHi,Oi, Hei, Feii are weakening, while intensities of forbidden transitions due [Nii], [Fevii], [Oi], [Oii], [Aiii], [Av], [Fevii], [Fex], [Fexi], [Fexi], [Nixv] are much more stable At the dispersion of our spectra, there is little evidence of activity in the nova shell during 1970. Temperature seems to be slightly increasing in the lower layers as well as in the external, low density regions.

Evolution du spectre de la Nova Delphini 1967 dans le proche infrarouge en 1969

Spectra of Nova Del 1967 have been obtained in the photographic infrared during the period March to November 1969. The gradient in the region 1.3–1.7 µ−1 has decreased from 3.06 in November 1968 to 2.57 in November 1969. The main spectral features occurring in the wavelength range 5800–9600 Å are described, while the profiles of some strong lines are displayed on Figures 2–6.

Raies nébulaires et coronales dans le spectre infrarouge de la Nova Delphini

Nova Delphini 1967 has been observed in the red and photographic infrared at the Haute-Provence Observatory from September 7 to November 12, 1968. Dispersions range from 230 Å/mm to 4 Å/mm. The slope of the continuous spectrum in the region 1.3–1.7 μ−1 leads to a gradient of 3.06, which did not appear to vary during the observing period. This gradient is, however, very different from the value 1.71 measured on plates secured in August 1968. Lines ofHi, Hei, Heii, Feii,Oi,Cii and forbidden transitions due toOi,Oii, Fevii, Fex, Fexi,Siii,Aiii,Av,Axi and Nixv have been identified. Their intensities at various dates are given in Table II. Line profiles could be measured for a few lines taken on a 39 Å/mm spectrogram on October 3. Hei λ 6678 and λ 7065 are displayed on Figures 2 and 3. Figure 4 gives the [Oii] doublet at λ 7319–7330, while the Hα profile, obtained on October 4 can be seen on Figure 5. The line extends over more than 45 Å and narrow absorptions are seen at λλ 6551.05; 6555.75; 6563.15; 6571.49; 6574.45. Due to the absence of published data on radial velocities of absorption lines in the visible spectrum at that time, it is not possible to give a clear identification for these features. Some of them may belong to Hα, while others are probably due to metals.

Far UV extinction and the interstellar 4430 band in the large magellanic cloud

The central depths of the interstellar 4430 Å band and far UV extinction for a sample of reddened LMC members are presented here.

SPECTROSCOPIC OBSERVATIONS OF 27 CANIS MAJORIS FROM 0.14 TO 4.7 MICRONS.

Results are presented for visual spectroscopy, uvby photometry, HKLM infrared photometry, and satellite UV observations of the Be star 27 CMa over the wavelength range from 0.14 to 4.7 microns. The visual spectrum between 3650 and 6800 A is found to consist mainly of the Balmer lines from H-alpha to H14 with complicated asymmetric profiles as well as He I lines exhibiting the same asymmetry as the Balmer lines. A model-atmospheres analysis indicates that the atmosphere of the central star can be represented by a model with an effective temperature of 20,000 K and a surface gravity of 6300 cm/sec per sec; a spectral type of B3 IV is suggested. Variations in the visual and UV regions are discussed, and the star is shown to exhibit an IR excess similar to that of other Be stars. A shell with a radius of approximately 17 solar radii, an electron density of no more than 590 billion per cu cm, and an electron temperature of 14,400 K is inferred.

Evolution du spectre de la Nova Delphini 1967 en 1971 et 1972

Continued spectroscopic observations of Nova Del 67 during 1971 and 1972 show a general decrease of the nebular and coronal emission with respect to the local continuum. The continuous spectrum exhibits a strong Balmer emission (figure 1). Equivalent widths of Hi, Hei, Heii, Oi, [Oi], Oii, [Oii], Oiii, [Oiii], Niii, [Sii], [Aiii], [Neiii], [Nev], [Fevi], [Fevii], [Fex], [Fexi], [Fexiv], [Nixvi], [Nixv] are listed in tables 1 and 2.Figures 5 to 10 show several line profiles, which can be interpreted in terms of a model proposed by Hutchings (1972). Kinematical properties of the nova envelope do not seem to have changed in the 1968–1972 time interval. However, a study of the [Oiii] (4959 Å) line indicates that the physical conditions in the polar blobs in 1972 (Te=10 660 K,Ne=5,5×105 cm−3) are different from those prevailing in equatorial rings (Te=9×100 K,Ne=7×105 cm−3).

New Spectroscopic Results for the Galactic B[e]-Supergiant MWC 314

MWC314 = BD + 14° 3887 was discovered by Merrill (1927) who found hydrogen and Fe II emissions in its spectrum. Very few spectroscopic observations of this object are available in the literature. Recently, Miroshnichenko (1996) reported results of its new photometric and medium—resolution 2 A) spectroscopic study. Analysing the SED and Balmer emission line profiles he concluded that MWC 314 is a highly reddened supergiant with a strong and slow stellar wind which could be considered as an LBV candidate.

The Spectrum of Nova Vulpeculae 1984 N°2 at Nebular Phase

Nova Vul 1984 n°2 has been again observed at Observatoire de Haute-Provence in the autumn of 1985, i.e. 270–295 days after maximum. It was then in the nebular phase. The spectra cover the blue-violet and the near infrared regions. Over 50 lines and blends have been identified and are given in Table 2. No clear pattern is observed in the emission bands of a width of about 1450 km/sec. The most conspicuous features observed are the forbidden NeIII and NeV lines. The infrared region is dominated by a very strong He I 1083nm emission.

Photographic Infrared Spectra of Symbiotic Stars

Relatively few spectra of symbiotic stars have been recently published in the photographic infrared. We have observed six objects during the period 1962–1977 with a grating spectrograph attached to the newtonian focus of the 120-cm telescope at Observatoire de Haute Provence. The reciprocal dispersion is 230 A.mm−1 and the region 5800 to 8800 A has been covered using hypersensitized IN plates. The minimum equivalent width for an emission line to be seen is about 0.5 A. The spectra are displayed on plates I and II. We now briefly review the main spectral characteristics.