COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS

                    NUMBER 428

                            Konkoly Observatory
                            Budapest
                            1970 April 12


        THE SPECTRUM OF NOVA SERPENTIS 1970

A series of spectra of the bright Nova Serpentis
1970 was obtained with the one-prism spectrograph attached
to the 99.5 cm reflector f/15 of the Hamburg Observatory
between March 10th and 21th, 1970 with a dispersion of
70 A/mm at H_gamma. The spectral range between 3900 A and 5250 A
was studied.
The emission lines of hydrogen, H and K lines of
Ca II and those of ionised iron are the most conspicuous
features of the spectrum of Nova Ser 1970. The most intense
emissions of Fe II belong to the multiplets 27,28,37,38
and 42. Furthermore, emission lines of He I lambda 4471.477A
(multiplet 14), those of Ti II multiplets 19 and 41, and
those of Cr II multiplet 44 are present. The investigation
of the fine structure of the emission lines has shown that
the line profiles are formed by superimposing of emissions
of different radial velocities. The velocities of these
emissions derived from red wings (violet being distorted by
the absorption) are given in Table 1.

                    Table 1.

              Radial velocities in km/s

Date                I      II    III   IV
1970 March 10.186   614   939   1272   1959
           12.179   690   886   1432
           14.154   782   933   1268
           21.134   675         1364   1872


The values in columns I-III correspond to data communicated
by J.Grygar and J.B.Hutchings in Circ.Bur.Cent.Int.Telegr.
Astr. No.2220 for the dates Feb.20th and 22th. A further
emission system was derived from Fe II multiplet 42 lines
and from hydrogen lines, their values are listed in column
IV of Table 1. Both profiles with higher velocities were
not observed for H and K lines of Ca II. The emission
profile III seems to be multiple. The width of H_delta is affected 
by the absorption line due to lambda 4122.638 A Fe II (28).
The shape of the bright emission is regular; only that of
H_gamma is distorted by superimposed emission and absorption of
the line lambda 4351.764 A Fe II (27).
      The strongest absorption lines belong to H I, Ca Il,
Fe II multiplets 27, 28, 37, 38 and 42, Ti II multiplets 19,
31 and 41, Cr II multiplet 44, and the line 4481A of Mg II
multiplet 4. The principal as well as the diffuse enhanced
spectrum were developed when Hamburg'e observation began.
Both systems were observed for H I, Fe II and Ca II lines
for Ti II only principal and for Mg II line lambda4481 A diffuse
enhanced spectrum were observed. The last line is blended
by the 4488. 319 A Ti II line. The absorption due to the
diffuse enhanced spectrum during the whole observational
period was stronger than the principal absorption except
for Ca II and H_gamma lines; the principal absorption of the
latter is affected by the diffuse enhanced absorption
lambda 4351.764 Fe II (27). The interstellar absorption of Ca II
was also present. The velocities of the principal and the
diffuse enhanced spectrum corrected for the orbital velocity 
of the Earth are given in the Table 2.

                           Table 2.

Radial velocities derived from absorption lines
                          FeII+   CaII   HI+          CaII
Date                H I   TiII    (U)    FeII   MgII   (K)
                               
1970 March 10.186   884   786            1662   1674
           12.179   827   746            1548   1503
           14.154   832   775     785    1613   1619  1466
           21.134   792   728     616    1616   1589

As can be seen from Table 2, the velocities of the principal.
spectrum derived from H I lines are higher than those derived 
from the Fe II and Ti II lines.
      Two additional spectra were obtained on 1970 April
4.123. An investigation showed the following differences to
the previous spectra;the emissions of Fe II became stronger
compared to the H_beta emission and new emission lines appeared
around lambda 4460 A. The Mg II absorption line lambda 4481 A weakened
substantially and also Fe II absorption lines became
fainter. The principal absorption of H I is strenghtened
relative to the diffuse enhanced one. Emission and absorption 
lines of Ti II did not change.
      For the difinitive study of the correlation between 
brightness of the nova and radial velocity changes it
is most desirable to give radial velocity data corrected
for the orbital velocity of the Earth, and to give the
time of the observation with an accuracy of one hundredth
of a day at least.

                      U.K.GEHLICH    J.TREMKO
                              R.WEHMEYER
                       Hamburger Sternwarte
                          205 Hamburg 80
                      Federal Republic Germany