The Atlas presents 36 MK standards distributed on 17 sheets
(Figs. 1 (click here) to 17 (click here)) illustrating the spectral type sequence and the
luminosities classes. The four following figures illustrate
some peculiar spectra: Am stars, composite spectra, metal
deficient stars and S and C stars.
All stars are listed in Tables 1 (click here) and 2 (click here): Table 1 (click here) refers to MK
standards and Table 2 (click here) to stars with spectral particularities.
The tables provide the identifications (HD and HR numbers,
name), the spectral classification, the equatorial coordinates
for equinox 2000.0, the visual magnitude, the B-V and R-I
colour indices, and lastly the number of the figures where the
spectrum of the star is illustrated.
The data were taken from Hoffleit & Jaschek (1982),
Garcia
(1989), Keenan & McNeil (1976) or from the SIMBAD data base
of the Centre de Données de Strasbourg.
Nine figures concern the spectral type sequence:
Eight figures illustrate the luminosity effects at the
following spectral types: F5-6, G0, G2, G5, K0, K2, K5, M2.
The F-type spectra in the figures permit to make the link with
Part I of the Atlas and are used also for comparison with the
Am stars.
In Table 3 (click here) we list the stars, ordered by spectral type and
luminosity class, so as to permit a quick overview of our
coverage. The stars are specified by their HD number.
All MK standards are taken from the list of Garcia (1989) which
integrates the different lists given by Morgan and Keenan and
their collaborators. The only exception is HD 61064 (F6III)
which figures only in the list of Morgan & Abt (1972).
An identification of the principal lines and features visible
on our spectra was made with the help of the solar spectrum
(Moore et al. 1966) and is given in Figs. 1 (click here) (dwarfs) and 9
(supergiants).
- Am stars: Fig. 18 (click here).
Even if these stars are of early type, we have included them in
this part of the Atlas because very often there do exist
confusions between the Am stars and the stars with composite
spectra when classified in the 3800-4700 Å region.
Table 3: MK standard stars ordered by spectral type and luminosity class
(identified by
and illustrated in Figs. 1 (click here) to
17 (click here))
Their presence in the Atlas shows that even in the near
infrared region there exists resemblance between an Am object
with a late metallic line type and a composite spectrum of an
early A type dwarf and an early G type giant, like in the case
of HD 27749, Am, and HD 59604, G2III+A2. The difference appears
in the TiI lines 8426 Å and 8435 Å which are very sharp in stars
with composite spectra. Also the appearance of the blend 8468 Å\
permits a separation between the two types of objects.
The three characteristics of the Am stars in our spectral
region are:
the OI 8446 Å line is generally narrow and deep,
the FeI 8688 Å line is also generally narrow and deep,
the CaII lines have a very particular aspect, because of
their narrowness and the blend with Paschen lines.
In Fig. 18 (click here) we show the spectra of two Am stars of very different
metallicities: HD 93903 has Paschen lines similar to those of
an A4-5 star, whereas the metallic lines (for instance FeI
8688 Å) correspond to an early F type; HD 27749 presents Paschen
lines similar to those of an A7 star, whereas the metallic
lines correspond to a late F type.
- Stars with composite spectra: Fig. 19 (click here).
The composite spectra are produced by the superposition of the
spectrum of an early type dwarf of type B or A and that of a
late G, K and M giant or supergiant. In the 3800-4800 Å region
generally the earlier type spectrum predominates, whereas in
the region here reproduced, the spectrum of the late companion
is little perturbed by the early type (Ginestet et al. 1994).
Figure 19 (click here) presents the spectra of the composites HD 59604-5 and
HD 184759-60:
In HD 59604-5 the hydrogen lines P12 and P14, as well as the OI
8446 Å lines show the presence of a hot object in the system. It
should be noticed that the P12 and P14 lines are very weakened
because they seem to correspond in intensity to an F2 object,
whereas the hotter component is really of type A2. The metallic
lines (CaII, FeI, TiI) permit to determine the type of the cool
star as being G2III.
In the case of HD 184759-60, the P12 and P14 lines of the
hotter companion are even weaker than in the previous case,
they seem to correspond to an F5 star whereas it is really of
type A. The metallic lines permit to classify the cool star as
being G8III.
- Weak lined stars: Fig. 20 (click here).
Figure 20 (click here) illustrates the spectra of three metal weak stars: one
dwarf HD 6582, 
Cas, one subdwarf HD 19445 and one giant HD
83632. These spectra are compared to those of two MK standards
of type G5V and K2III.
In the spectrum of HD 19445 the CaII lines are very weak and
the metallic lines have practically disappeared, except FeI
8688 Å which is faintly visible. The classification attributed
in the blue, G5 is difficult to justify a priori on the basis
of the near infrared.
HD 83632 appears at a first glance to be a dwarf, but the depth
of CaII is larger than in dwarfs and moreover the weakness of
FeI 8688 Å does not correspond at all to a dwarf.
- S and C stars: Fig. 21 (click here).
Figure 21 (click here) shows the spectra of four S and C stars: BD 
2267
and HD 112127 may be classified as giant K stars; ZrO bands are
weakly noticeable in their spectrum. HD 187796 (
Cyg) presents
the CaII triplet in emission and enhanced absorptions of TiO
whereas HD 92839 is strongly marked by the rotation bands of
the red system of CN. The search of the molecular bands was
made with the help of Pearse & Gaydon (1963) for CN,
Solf
(1978), Huang et al. (1994) for TiO,
Davis & Hammer (1981)
for ZrO.