COMMISSION 27 OF THE I. A. U.
              INFORMATION BULLETIN ON VARIABLE STARS
                          Number 3417
                
                                                Konkoly Observatory
                                                Budapest
                                                10 January 1990

                                                HU ISSN 0374 - 0676



           A T TAURI STAR WITH STRONG [S II] EMISSION LINES

 The forbidden lines are important in T Tauri stars because they probe the outer parts of the
stellar wind and they also give indirect evidence for the presence of disks around the star.
We have secured spectra in the vicinity of NGC 7000 (the North America Nebula) and IC
5070 (the Pelican Nebula), as part of a multifrequency study of young pre-main sequence stars
in star forming regions. The spectroscopic observations have been carried out from August 24
to 27, 1989 with the CARELEC spectrograph (plus an RCA CCD detector) attached to the
1.93 m telescope of the Haute-Provence Observatory. The dispersion was 260 A/mm in the
lambda 3700-7500 A range. The 3.2" width slit led to a spectral resolution of about 8 A. For details
of the reduction techniques and spectral classification scheme cf. Mendoza et al. (1990). We
report herein only the spectrum of LkH-alpha 155 (in the Pelican Nebula).

 This spectrum (spectral type K3, approximately) shows strong hydrogen lines (W(H-alpha) =98.8 A and
W(H-alpha) = 36.7 A) and forbidden lines. He I (lambda 5876 and 7065 A), [O II] (lambda 3727-9 A) and Na
I (D) are present. The TiO bands are weak. Fe II(lambda 4924 A) is most likely absent and Fe II ( lambda
5018 A) is very weak, if any. The telluric bands (lambda 6277, 6872 and 7192-7272 A) are present;
the O I line (lambda 5577 A) is present. The most outstanding spectral feature are the [S II] (lambda 6717
plus lambda 6731 A) emission lines (W([S II]) =16.7). The Balmer emission lines, Fe II (42) and the
(S II)-doublet do not display clear evidence of P-Cygni profiles (see Fig. 1).

 There is no H2O Maser known nearby to LkH-alpha 155 (see Cesaroni et al., 1988). However,
there exists an IRAS source close to this object (about 1' N), 20496+4354; however, LkH-alpha 155
lies outside of the uncertainty ellipse of this IRAS point source. Under the assumption that
LkH-alpha 155 is embedded in this IRAS source, then the luminosity, derived from the infrared fluxes
is around 74 L_Sun. A value higher than typical bolometric luminosities of classical T Tauri stars (Imhoff and Mendoza, 1974).

 LkH-alpha 155 deserves further study, in particular CCD imaging in U, B, V, H-alpha and [S II] will
decide about the T Tauri star and the infrared source. To have a good model of this object it is
necessary to acquire high spectral resolution for both the forbidden and the hydrogen lines.

 One of us (E.M.) wishes to thank to DGICYT of the Education and Science Ministry (Spain)
which has made possible his stay at the Instituto de Astrofisica de Andalucia.

                            [FIGURE 1]

            Fig. 1.- The spectrum of LkH-alpha 155



      E.E. MENDOZA *1, Y. ANDRILLAT 2, and A. ROLLAND 1

  (*) On sabbatical leave from Instituto de Astronomia, UNAM.
  (1) Instituto de Astrofisica de Andalucia
  (2)  Laboratoire d'Astronomie (072), Universite de Montpellier II
    Place Eugene Bataillon - 34095 Montpellier Cedex 2, et URA 1281 (OMP).



 REFERENCES

Cesaroni, R. Palagi, F., Felli, M., Catarzi, M., Comoretto, G. Di Franco, S. Giovanardi, C. and Palla,
    F.: 1988 Astron. Astrophysics Suppl., 76, 445 [BIBCODE 1988A&AS...76..445C ]
Imhoff, I., and Mendoza, E. E.: 1974 Rev. Mexicana Astron. Astrof., 1, 25 [BIBCODE 1974RMxAA...1...25I ]
Mendoza, E.E., Andrillat, Y., and Rolland, E.: 1990 in preparation