Yvette Andrillat

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.

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).

Spectres de quelques toiles Be entre 7000 et 9600

Kodak IM plates have been used in order to extend to 9600 Å the observed wavelength range for 23 O, B, Be Bp and A stars. The spectra are shown in the plate. Several atmospheric absorption bands perturb the continuum and line spectrum. Between 1.45 and 1.20μ-1, we have measured the parameter d logIλ/d(1/λ). The results appear in the table and indicate that Be stars do not exhibit anomalous reddening in this spectral region. On the other hand the above parameter is much more sensitive to the reddening than to the stars effective temperature.

Spectre continu dans le proche infrarouge de deux toiles Be: HD 50138 et HD 51585

Continuous spectra of the Be objects HD 50138 and HD 51585 have been investigated between 1.6 and 1.2μ-1. The infrared gradientφIR of HD 50138 (B5eV) is found to be 2.09±0.10, while the typical B5V star π And indicatesφIR=1.17. A B5V (HD 16219) star located at about the same distance as HD 50138 hasφIR=1.29 and it is shown that interstellar reddening may account forΔφIR between HD 16219 and π And. The difference in gradient between HD 50138 and HD 16219 (ΔφIR=0.8) may be explained by a continuous reemission in a lenticular envelope with a radius equal to 4R*. The peculiar object HD 51585 exhibits a B0.5 continuous spectrum, for which the value d logIλ/d(1/λ) should be 1.13 according to model atmospheres computations. The distance as derived from color excess leads to disagreement between measured and computed (for a B0.5 star) values of d logIλ/d(1/λ). The reddening may be explained by reemission in an envelope the radius of which is smaller than 5R*. In conclusion, the narrowness of the spectral range under consideration does not permit to decide whether the observed reddening is due to recombination to the third level of the hydrogen atom or whether it is part a thermal reemission in a circumstellar cloud at lower temperature, as it has been observed around 10 μ by various authors.

Infrared Spectra of Nova Delphini 1967

Infrared spectra at 39 A/mm of Nova Delphini 1967 have been obtained in the wavelength range λ 6500– λ 8800. Typical microphotometer tracings are displayed and an estimate of the received flux is given for the most prominent lines at nebular stage. Loss of matter is very likely to occur.

Spectres de NGC 1976, IC 4997, NGC 6572 et IC 418 dans le Proche Infrarouge Photographique

Une description qualitative des spectres d’une vingtaine de nebuleuses planetaires dans la region du proche infrarouge a ete publiee en 1961 (Andrillat et Andrillat, 1961). Le spectrographe E’ monte sur le telescope de 120 cm de l’Observatoire de Haute-Provence nous a permis d’entreprendre l’etude spectrophotometrique de quelques-unes de ces nebuleuses planetaires, ainsi que celle de la nebuleuse d’Orion. Ce spectrographe, pourvu d’un reseau par transmission de 300 traits au millimetre assure une dispersion pratiquement constante de 230 A/mm dans le domaine de 5750 a 8000 A. Les spectres obtenus sur plaques IN hypersensibilisees a l’ammoniaque, ont ete calibres photometriquement a l’aide d’un spectrographe a penombre decrit par Barbier(1944).

Observation des Nébuleuses Planétaires dans L’Infrarouge

La region de l’infrarouge a ete fort peu etudiee jusqu’a maintenant en astrophysique. En ce qui concerne les nebuleuses planetaires les seuls travaux publies concernent la region de l’infrarouge photographique jusqu’a 1·2 μ.