CRDF grant RP1-2264
Main scientific results
The first period
During the 1-st period high resolution CCD-spectra
of the fast evolving hypergiant IRC+10420, obtained in
1997-2000 with the 6-meter telescope, were processed.
Radial velocities of numerous emission and absorption
lines, including HI profiles, were measured.
The spectral type, effective temperature and luminosity
were estimated using spectroscopic criteria only. Now
we analyze the results obtained for this peculiar object.
New high resolution spectra of the fast evolving star
FG Sge were obtained with the echelle spectrometer
PFES at the 6-m telescope. Fundamental parameters and
detailed chemical composition were determined using the model
atmosphere metod. We have been monitoring this fast evolving
object spectroscopically since 1994:
a sample of the FG Sge spectra is posted on-line.
New spectra of the LBV-object HD168625 B6Ia+, two
LBV-candidates, HD168607 (B9Ia+) and AS314 (A0Ia), and two
peculiar Be-stars MWC1080 and AS381 were processed. They were
obtained with high resolution CCD-echelle spectrometers LINX
and PFES at 6-m telescope. Relative intensities, radial
velocities for some hundred of lines were measured and typical
profile shapes were obtained. A spectral atlas for HD168625,
HD168607, AS314 and the normal supergiant HD183143 B7Ia was
prepared for publication.
The main purpose of the investigation of the first three
objects are a clarification of the models of their winds
and an attempt to get the additional spectroscopic differences
between the true hypergiants and theirs simulations by the
low-mass stars. The clarification of the nature and the
evolutinary state is the task of the investigation of the
two last objects.
The observing mode of the echelle-spectrometer LYNX in
combination with the circular polarization analyzer was
developed and tested at the Nasmyth focus of the 6-meter
telescope. The modernization of the existing spectrometer
PFES inside the prime focus cage of the 6-meter telescope
has started, aiming at measurements of linear polarization
in high-resolution spectra. The complete set of optical
components for this observing mode are now available.
Current results of a study of sample of stars evolved from
AGB to the planetary nebulae stage were presented as a short
review: Klochkova V.G., Panchuk V.E., Szczerba R. "Optical
spectroscopy of selected PPN candidates", which will be
published in Astrophysics and Space Science, 2001.
The second period
Based on CCD-spectra obtained with echelle-spectrometers
at the 6-m telescope, we have determined fundamental
parameters and detailed chemical composition of the far
evolved object associated with the OH/IR-star IRAS18123+0511.
Metallicity and chemical composition of the optical
counterpart of the OH/IR-star IRAS18123+0511 were determined
for the first time. The overall pattern of chemical
abundances confirms the AGB evolutionary stage for the object
IRAS18123+0511. The metallicity, in combination with the
radial velocity Vr=+78.0 km/sec and a high galactic latitude,
indicates that the object likely belongs to the old disk
population. The expansion velocity of the circumstellar
envelope V_exp=21 km/sec is estimated from positions of
absorbtion features, which are formed in the envelope.
results are presented in the paper: Klochkova V.G., Panchuk
V.E., Tavolganskaya N.S. "Optical spectra of 3 stars at the
asymptotic branch stars", which will be published in a
Russian journal "Astronomy Reports", 2001.
During the reporting period we analyzed spectroscopic data
for the fast evolving supergiant IRC+10420. These data were
obtained in 1997-2000 with the echelle spectrometer of the
6-m telescope and processed in the previous quarter. The
radial velocity (with respect to the local standard of rest)
of IRC+10420 has been found to be 93 km/s from pure
absorption lines without visible emmision components (HeI,
OI, NI, SiII) and from absorption components of the Balmer
hydrogen lines. Both emission and absorption lines show
correlations between radial velocities and oscillator
strengths. A variability of the relative intensity of the
Halpha and Hbeta emission components has been revealed. The
spectral type A2 was estimated from the IRC+10420 spectrum
obtained in 2000, and this corresponds to an effective
temperature of 9200K. We have concluded that IRC+10420 is
evolving rapidly to the Wolf-Rayet stage, and that the
current rate of temperature increase is 120K per year. The
luminosity based on the OI, 7773A triplet strength is equal
to Mbol=-9.5 mag. All optical spectra of IRC+10420 show a
helium absorption line HeI 5876 A with a significant
equivalent width of no less 200mA, at such a low effective
temperature it could be caused by both the very high
luminosity and the helium abundance excess in the atmosphere
of the supergiant.
The results are presented in the paper:
Klochkova V.G., Yushkin M.V., Chentsov E.L., Panchuk V.E.
"Evolution alternations in optical spectra of peculiar
supergiant IRC+10420", which was submitted by a Russian
journal "Astronomy Reports" in March 2001.
The detailed spectral atlas of pre-planetary objects and
B-A supergiants is close to completion. The atlas includes
V1853 Cyg, IRAS18062+2410, MWC162 and the central star of the
planetary nebula NGC6543. The spectral range is 4300-7800 AA,
the spectral resolution limit is 0.5 A. The interesting
variations of the radial velocity and the line profiles in
the spectrum of AS314 are revealed and investigated. They
are especially appreciable between the seasons of 1998 and
2000 and could point to the nonsphericity of the wind or to
the spectral duplicity.
New techniques for carrying out observations with the
echelle-spectrometer LYNX at the Nasmyth focus of the 6-meter
telescope, using the circular polarization analyzer in
combination with a half-wave plate, were prepared and
tested. The half-wave plate provides a phase shift
"lambda/2". Inserting a half-wave plate before an analyzer,
we change locations of echelle orders with left and right
circular polarization. This permits us to minimize methodic
errors caused by the locations of echelle orders with left
and right polarization at different places on the CCD. The
design of such an adapter allows us to input either a
half-wave or a quarter-wave plate. Additionally, we can
rotate the quarter-wave plate. That permits us, in principle,
to use the echelle-spectrometer LYNX to measure all 4 Stokes
parameters (the possibility of such an extended usage of the
spectrometer LYNX will be better understood after
investigation of instrumental polarization in the Nasmyth
focus of the 6m telescope).
The observing mode is described
in a paper: Panchuk V.E., Klochkova V.G., Najdenov I.D.,
Romanenko V.P., Yushkin M.V. "Spectroscopic complex of the
Nasmyth focus of the 6m telescope. Fast echelle-
spectropolarimeter." Preprint of the Special Astrophysical
The reconstruction of
the echelle-spectrometer PFES in the
prime focus of the 6m telescope was completed, aiming at
measurements of linear polarization. As a result, we now have
the possibility to provide different position angles of the
spectrometer inside the prime focus cage.
A linear polarization analyser for the spectrometer PFES has
been made. The analyser consists of two CaCO3 crystals
oriented at an angle of 90 degrees with respect to each
other. The design of the analyser enables the same optical
path for ordinary and extraordinary beams and provides the
same intensity for both polarized beams after the diffraction
gratings of the spectrometer.
An additional cross-disperser grating was bought to increase
the separation between echelle orders.
This new observing
mode is described in a paper: Panchuk V.E., Klochkova V.G.,
Yushkin M.V., Romanenko V.P., Najdenov I.D., Ermakov S.V.
"Echelle-spectropolarimeter for the prime focus of the 6m
telescope." Preprint of the Special Astrophysical
Methods to extract echelle spectra obtained with a linear
or circular polarization analyzer have been developed. The
Stokes parameter determination procedure has been developed.
The procedure takes into account a wavelength shift between
spectral order components. This package has been developed
inside the MIDAS software environment (version 01FEB) using
the standard procedures in the "Echelle" and "Spec"
In January 2001 we performed the first observations to
measure linear polarization in a high spectral resolution
mode at the 6m telescope. The echelle spectrometer PFES
inside the prime focus cage of the 6m telescope, in
combination with a spectropolarimetric analyzer, was used for
registration of linear polarization in the spectra of several
spectropolarimetric standards and some program stars. We
obtained spectropolarimetric data in a spectral range
4950-6620 A with spectral resolution R=15000 for 21
To illustrate the observations, we present echelle
frames for the peculiar supergiant
and for the famous bipolar nebula
AFGL2688 (Egg Nebula).
The first results and the initial experience gained in
spectropolarimetry in a high spectral resolution mode allow
us to begin the project of a specialized spectropolarimeter for
the prime focus aiming for measurements of the 4 Stokes
The third period
From CCD-spectra obtained with the echelle-spectrometer of
the 6-m telescope, the fundamental parameters and detailed
chemical composition of the star HD 331319 are determined. This
star is the optical counterpart of the IR-source IRAS19475+3119.
In the spectrum of this high luminosity object (Mv < -8) with an
effective temperature of Te ~ 7250 K, helium lines were found to
indicate a significant helium excess in the outer atmospheric
layers. This may be evidence of possible helium synthesis during
the course of previous evolution.
The nitrogen and oxygen overabundances were found to be
[N/Fe]_sun=+1.30 dex and [O/Fe]_sun=+0.64 dex, even though the
star shows a very small carbon excess. The metallicity [Fe/H]_sun
= -0.25 for the stellar atmosphere is not significantly
distinquished from the solar value. The determined abundance of
s-process metals Y, Zr [X/Fe]_sun = -0.68 is not overabundant;
rather, it is somewhat underabundant relative to the metallicity.
We also find [Ba/Fe]_sun = -0.47. Other heavy elements such as
La, Ce, Nd, Eu are slightly enhanced relative to iron: their
averaged abundance [X/Fe]_sun = +0.16. In sum, the chemical
abundances pattern confirms the post-AGB evolutionary stage for
the object IRAS 19475+3119. The ratio O/C > 1 derived for the
atmosphere of the central star agrees with details observed in
the radio region. The object's metallicity, in combination both
with the radial velocity value RV = -3.4 km/sec and with the
galactic latitude |b| = 2.7 degrees, suggests that it is located
in the galactic disk.
The expansion velocity of the circumstellar envelope, V_exp, is
found to be approximately 21 km/sec measured from the wavelengths
of absorption lines formed in the envelope.
In addition to the results for HD 331319, interesting results were
also found for a standard star. Comparing the results obtained in
this study for the standard star (a typical post-AGB star),
HD161796 = IRAS 17436+5003, with data published earlier, we found
evidence for an evolutionary change of its effective temperature
with a rate of at least 50K per year. (Klochkova V.G., Panchuk
V.E., Tavolganskaya N.S.)
Two new spectra of the post-AGB star IRAS22223+4327 have been
analyzed. The spectra have been obtained with the echelle
spectrometer NES (R=30000) and echelle spectrometer PFES
(R=15000) of the 6-m telescope BTA. The high resolution spectrum
was used for the determination of atmospheric parameters and for
calculations of chemical composition using a model atmosphere
comparison. The model atmosphere used had parameters of
Teff=6500K, log(g)=1.0, V_t=5.0 km/s; these are in good agreement
with atmospheric parameters published for the star. The
metallicity and details of chemical composition of the star
indicates a value of [Fe/H]=-0.3.
In the high resolution spectrum we have resolved four absorbtion
components of the NaI D1,D2 lines. One of them is likely to be
associated with the interstellar medium, one with the stellar
atmosphere, and the two strongest components are associated with
the circumstellar envelope. In the PFES spectrum we have detected
C_2 bands of the Swan system; (0,0) and (1,1) are found to be in
absorption, while (0,1) and (1,2) are in emission. In addition,
we have detected CN bands of the Red system (2,0),(3,0) and (4,0).
(Klochkova V.G., Panchuk V.E., Yushkin M.V.)
The work on the spectral atlas of hypergiants is completed. It
includes: graphs of spectra of HD168625 (B6Ia+), HD183143 (B7Ia),
HD168607 (B9Ia+), and AS314 (A0Ia) between 4700 and 6700
angstroms; tables of the identified lines and averaged radial
velocities for the groups of lines; and typical line profiles and
their variability with a time. The spectrum from the last season
for hypergiant AS314 revealed interesting time variations of the
profile shapes. (Chentsov E.L., Ermakov S.V., Klochkova V.G.,
Panchuk V.E., Bjorkman K.S., Miroshnichenko A.S.)
Aiming for linear polarization measurements, the design of
for Cassegrain focus of the 1-m telescope of the
Special Astrophysical Observatory is completed. The device, which
has two changeable diffraction gratings (1200 and 600 grooves/mm),
provides a spectral resolution of R=1100 and R=2300, respectively,
at 2.5 pixel projection of the entrance slit. A fixed symmetric
analyzer is installed behind the slit. The layout of the
spectrometer and the design of the CCD's cryostat allow changes
to the position angle of the spectropolarimeter. The diameter of
the collimator (F/6.5), the size of the ruled area of the
gratings, and the size of the input pupil of the camera allows us
to use all starlight up to seeing values of 3.5 arc sec. A
changeable input aperture also allows usage of the device as a
spectrophotometer. At present, the spectropolarimeter is
undergoing testing in the laboratory. (Panchuk V.E.)
Some different techniques for measurement of all 4 Stokes
parameters at the Nasmyth focus of the 6m telescope are have been
analyzed. The technical design for manufacturing of the unit to
provide the counter-rotation of the polarimetric vector at the
entrance of the spectropolarimeter has been prepared.
(Panchuk V.E., Najdenov I.D.)
In addition, an analysis of various possible layouts for a
high resolution spectropolarimeter for the prime focus of the 6-m
telescope was performed. (Panchuk V.E.).
The fourth period
At the beginning of this period the visit by the U.S. team to the
SAO 6-meter observatory was completed. It was a very successful
visit, enabling the teams to carry out detailed discussions of science
goals and instrument development. It also allowed the U.S. team
to become more familiar with the capabilities and observation modes
of the 6-meter telescope and instrumentation. At present, plans for
the reciprocal visit of the FSU team to the U.S are made, and
the application process for visas is underway. The visit is expected
to occur during November 2001. Communication between the
U.S. and FSU teams continues via e-mail at this time.
During the reporting period 2 successful observing runs
were completed at the 6-meter telescope. In July (02-07) we
obtained numerous spectra of LBV and faint protoplanetary candidates
with the prime focus echelle spectrometer PFES (resolving power
R=15000). In August (09-10) we obtained several high-resolution
spectra (R=25000) of our program objects: MWC297, MWC342, MWC623,
VXCas, IRAS01005+7910 with the echelle spectrometer LYNX.
The algorithms for spectropolarimetric echelle frame reduction
were improved. These algorithms were tested using spectra of
polarimetric standards. To illustrate this we present 3 figures
(the postscript figures are appended in a separate e-mail message).
In Figure 1
a fragment of the polarization spectrum of a standard
star HD204827, in a region containing the HeI 5876 A photospheric
line and the NaI 5890 and 5986 A interstellar lines, is shown.
The polarization level for both the continuum and the photospheric
line spectrum is in agreement with the broadband polarimetry of the
star, which has a polarization in the V-band (centered at 5500 A)
Pv=5.4%. However, the interstellar sodium doublet has a different
degree and position angle of polarization. We are working to
understand the origin of the polarization change across the sharp
sodium lines, which may be an artifact of the reduction process
rather than a real effect. Further work will be required to
understand the implications of this result.
A fragment of the polarization spectrum of a variable star R CrB
is shown in Figure 2
. Both the narrow and broad components of the
sodium doublet at 5890 and 5896 A, originating in the circumstellar
medium, are seen. The polarization level of these emission lines
is the same as in the nearby continuum. Studies of such spectra
may provide insight into the understanding of the R CrB phenomenon.
A fragment of the polarization spectrum in the H-alpha region of a
Be star is shown in
Figure 3 . The polarization level of the emission
line core is decreased with respect to the broad wings and to the
nearest continuum, as is expected for depolarization effects due
to increased emission of H-alpha in the circumstellar envelope.
(Panchuk V.E., Yushkin M.V.)
Other science efforts for the project were also continuing, as
described in the following items:
In the previous quarter the spectra of the peculiar object IRAS
19475+3118 (associated with the star HD 331319) were analyzed. The
fundamental parameters and detailed chemical composition of the
object were determined. In the spectrum of this high luminosity
object (Mv < -8 mag.) with an effective temperature of approximately
7250 K, helium lines were found to indicate a significant helium
excess in the outer atmospheric layers. This may be evidence of
possible helium synthesis during the course of previous evolution.
More details were presented in the previous report. V.G. Klochkova,
V.E. Panchuk and N.S. Tavolganskaya prepared the paper
"HD331319 - post-AGB F-supergiant with HeI lines in the spectrum",
which was submitted and accepted by the Russian journal "Astronomy
Reports" and will be published in January 2002.
The work on the spectral atlas of super- and hypergiants was
continued in connection with obtaining new spectra of HD 183143,
HD 168607, AS 314 and HD160529 in June 2001. The last
star (HD 160529) was also included in the atlas.
The atlas is ready for publication: Chentsov E.L., Ermakov S.V.,
Klochkova V.G., Panchuk V.E., Bjorkman K., Miroshnichenko A.S.
"Spectral atlas of of B2-B6 hyper- and supergiants in 4800-6700
AA". Preprint Spec. Astrophys. Observ., 2001.
In addition, 19 spectra of HD168625, HD168607 and AS314 obtained
from 1992 up to 2001 were prepared for modeling of their line
profiles, aiming at a study of their stellar winds. All these
spectra, as well as spectra of stars observed on the program "Young
intermediate-mass stars" were processed in MIDAS system
(Chentsov E.L., Klochkova V.G., Ermakov S.V.).
As discussed in the previous report, we reduced and analysed
two high resolution spectra of the faint evolved star K413, a member
of the globular cluster M12. It should be noted here that our
spectra are the first high resolution spectra for members of M12
at all. Based on results derived for the star K413 during the
reporting fourth period we wrote up a paper for submission to A&A.
The paper "K413, a star near the AGB in the globular cluster
M12" by V.G. Klochkova and N.N. Samus has been accepted by A&A.
We completed a study of the emission-line A-type star IP Per based
on the results of high- and low-resolution spectroscopic and
broadband multicolour photometric observations. The high-resoltuion
data were obtained with the echelle spectrographs LYNX and PFES.
The star's fundamental parameters were derived as follows:
Teff approximately 8000 K, log g approximately 4.4, log L/Lsun
approximately 1.0. We also found that the metallicity of the
object's atmosphere is nearly 40 per cent that of the Sun.
Our result for the star's gravity implies that it is located
at the zero-age main-sequence. We conclude that IP Per is a
pre-main-sequence Herbig Ae star, and belongs to the group of
UX Ori-type stars showing irregular photometric minima. These
results were reported in the paper "The pre-main-sequence star
IP Per" by A.S.Miroshnichenko, K.S.Bjorkman, E.L.Chentsov,
V.G.Klochkova, R.O.Gray, P.Garcia-Lario, and J.V. Perea-Calderon.
The paper was accepted by A&A.
Main optical elements for the spectropolarimeter of the prime
focus of the 6-m telescope (echelle grating, cross-dispersion
prisms, camera lenses, half-wave and quarter-wave plates) were
produced and acquired. Two modes of the cross dispersion unit
(classical echelle spectrograph mode and spectropolarimetric
mode) were tested in the laboratory. In the first mode the echelle
frame covers the range 3900-9000 AA and the range 4000-7000 AA
in the second mode. Parameters of the new spectral device will be
essentially improved in comparison with the existing echelle
spectrometer PFES: the spectral resolution will be increased by 1.4
times, the number of spectral elements registered by 1.7 times,
and the throughput by 2 times. The spectropolarimetric mode will
allow us to measure both linear and circular polarization.
Based on a review of published information on stellar spectro-
polarimeters, a program to develop equipment for stellar spectro-
polarimetry at the 6-m telescope is proposed (Klochkova V.G.,
Panchuk V.E., and Romanenko V.P. Stellar spectropolarimeters.
Preprint SAO N156, 2001).
The fifth period
During the time of this report, the reciprocal visit of the FSU
team to the U.S. occurred. The FSU team (V. Klochkova and
V. Panchuk, Special Astrophysical Observatory) visited the
Ritter Observatory of the University of Toledo, Toledo, OH,
USA. The travel was funded from the CRDF award to the FSU team.
The visit at the Ritter Observatory lasted over 3 weeks in
November 2001. While meeting together, we continued discussions
of the collaborative science projects that are underway.
Discussions about options for introducing polarizing optics to
the high resolution spectrometer NES, recently developed at the
6m telescope by V.Panchuk, have also been held. We have
discussed the results of the data reduction and calibration for
some polarization standards observed at the 6m telescope with the
Prime Focus Echelle Spectrograph (PFES) through a linear
polarization analyser. We also discussed the data reduction
pipeline and interpretation of the data obtained in the
framework of the CRDF project. Plans for follow up observations
and suggested calibration tests were made. We discussed
forthcoming joint publications. Preparations for a poster paper
describing our joint project (to be presented at the January
2002 meeting of the American Astronomical Society) were carried out.
A seminar on spectroscopic and spectropolarimetric devices at
the 6m telescope was presented on November, 15, 2001. Primary
astrophysical results from the FSU team, based on the
observational data obtained with the devices mentioned above,
concerning post-AGB stars, A- and F-supergiants, and hypergiants
The FSU team visited the Catholic University of
Valparaiso (Valparaiso, IN) aiming at a joint scientific
discussion on proto-planetary nebulae with Prof. B. Hrivnak, a
well-known researcher in this field. The FSU team's results on
high resolution spectroscopy of such objects were presented
there. These results are significant to understanding the
processes of stellar nucleosynthesis and evolution of
intermediate-mass stars after the main sequence phase.
During the visit, the FSU team was acquainted with spectral
devices at the Ritter Observatory and software for 2-dimensional
spectra processing. We have discussed advantages of the packages
used for spectroscopic data reduction at the Ritter Observatory
and at the Special Astrophysical Observatory.
We have also discussed a possibility to use new observational
facilities at the 6m telescope to select new targets for follow
up high resolution spectroscopy.
Science efforts for the project are continuing, as described in the
During the period reported we reduced and analyzed new
spectra of the peculiar hypergiant IRC+10420, associated with a
very distant IR-source, one of the brightest in the sky at 20
microns, whose spectral monitoring has continued at the 6m
telescope since 1992. A strong double-peaked emission in the
H-alpha line was found in 1985 and explained in terms of a
rotating equatorial disk model, first proposed by Jones et al.
(1993) for this object. All the spectra we obtained between
1992 and 2000 contained a complex emission-absorption H-alpha
profile, many emission lines of FeI, FeII, TiII, CrII, ScII, as
well as forbidden lines of [OI], [FeII], and [CaII]. Both
emission and absorption lines show a correlation between their
radial velocities and oscillator strengths. Variability of the
relative intensities of the H-alpha and H-beta emission
components was found. All optical spectra of IRC+10420 show the
HeI 5876 A absorption line with a large equivalent width of not
less than 200 mA, which might indicate an evolutionary helium
Based on high resolution optical spectra we obtained in 1995,
the effective temperature Teff=8500K has been estimated for
IRC+10420. Based on the optical spectrum of 2000 we estimated
its spectral type as A2, which corresponds to Teff=9200 K.
The strength of the OI IR-triplet at 7774 A led us to a luminosity
estimate of Mbol=-9.5 mag. We concluded that IRC+10420 is rapidly
evolving to the Wolf-Rayet stage. The average rate of the
temperature increase over more than 25 years is 120 K a year, with
a current rate of 160 K a year. These results have been accepted by
Astronomy Reports for publication in January 2002 (V.Klochkova,
M.Yushkin, E.Chentsov, V.Panchuk).
We completed a study of the emission-line star AS 381 based
on the results of optical and near-IR spectroscopic and
broadband multicolor photometric observations. The spectrum of
AS 381 indicates the presence of both a hot (early B-type) and
a cool (K-type) star in the system. A high interstellar
reddening (\approx 7 mag.) suggests that it is located at a
distance greater than 3 kpc, and the companions have luminosity
types II or higher. The emission-line profiles indicate that
the system is surrounded by a flattened circumstellar envelope,
which is viewed close to pole-on. The hot companion is found to
be approximately 2 mag. brighter in the V-band and more massive
(approximately 20 Msun) than the cool one (approximately 7 Msun).
The strong line emission and the position of the companions in the
Hertzsprung-Russell diagram indicate that the system is
experiencing mass exchange. We suggest that AS 381 is the first
B[e] supergiant binary discovered in the Milky Way. The results
are presented as a paper, accepted for publication by Astronomy
and Astrophysics (A.S.Miroshnichenko, K.S.Bjorkman, E.L.Chentsov,
V.G.Klochkova, O.V.Ezhkova, R.O.Gray, P.Garcia-Lario,
J.V. Perea-Calderon, R.J.Rudy, D.K.Lynch, S.Mazuk, C.C.Venturini,
We began preparation of a spectral atlas, which includes
spectra of 3 post-AGB stars of different effective temperatures
at different phases of evolution after AGB.
The optical elements for the prime focus spectropolarimeter
were tested in a laboratory conditions.
The 6th period
The project continues, with discussions between the US and FSU
teams being carried out via e-mail. We fulfilled 2 observing
runs at the 6-meter telescope, using the high resolution
spectrometer NES, and obtained high resolution spectra for the
program stars IRAS01005+7910 and CI Cam, and for several
Main science efforts were directed to preparation of several
joint papers and reports, as described below.
We finished a paper reporting the results obtained during
an initial phase of the spectroscopic monitoring of a
poorly-studied proto-planetary nebula (PPN) candidate
IRAS01005+7910 at the 6-m telescope of the Russian Academy of
Sciences. Its IRAS colors are similar to those of PPNe. However,
in contrast to most of the PPNe, the maser emission from
IRAS01005+7910 has been detected neither in CO nor in OH bands.
So far only low-resolution spectra of IRAS01005+7910 have been
published, where the object was classified as a B2Ie star.
For the first time, we accomplished a careful spectral line
identification and measured the line parameters in the spectra of
IRAS01005+7910. As a result, significant variability of the
optical spectrum was detected. We found absorption lines of CII,
OII, NII, AlII, SiIII, and MgII (4481A), as well as emission
lines of SiII and [FeII]. Both absorption and emission
components are present in the Balmer lines, NaI resonance
D-lines, HeI, and FeIII lines. The HeI line profiles vary from
straight to inverse P Cyg-type on a timescale of days to
months. The resonance NaI lines show 5 absorption components at
a resolution of R=60000. Additionally, the NaI D2 line exhibits
a variable emission component with a width comparable to that
of the Balmer line emission components. We estimated the MK type
of IRAS01005+7910 as B2Ia (T_eff about 21000 K). We suggest
that IRAS01005+7910 is a high-luminosity early-B type star,
surrounded by a non-spherical gaseous envelope with both
observable accretion and outflow. The envelope geometry and
weakness of the emission-line spectrum may indicate binarity of
the system. The object is most likely located at the horizontal
evolutionary track on its way to the PN region. The paper
"Discovery of spectral variations of the optical counterpart of
IRAS01005+7910" by V.G.Klochkova, M.V.Yushkin,
A.S.Miroshnichenko, V.E.Panchuk, and K.S.Bjorkman, was submitted
to A&A on 2002 March 1.
Based on multicolour photometry and spectroscopy both in the
optical and IR-region obtained at several telescopes, we tried
to clarify the nature and evolutionary state of the peculiar
emission-line star V669 Cep=IRAS22248+6058. The optical spectrum
of V669 Cep is remarkable due to extremely strong and variable
emission in the H alpha line. The presence of forbidden lines
in the spectrum allows us to classify V669 Cep as a B[e] object,
a new member of the category of Be stars with warm dust. Overall,
the results of our observations suggest that V669 Cep is most
likely a mass-exchanging binary system with both hot (B4-B6
low-luminosity star) and cool (K-type star) stellar components
surrounded by a non-spherical gaseous-and-dusty envelope. The
cool component manifests itself through CN and CO absorption
bands in the near-IR spectrum. The spectrum and spectral energy
distribution of V669 Cep are similar to those of another binary
Be star (AS381) that we studied earlier. The paper "V669 Cep:
A new binary system with a B[e] star" by A.S.Miroshnichenko,
K.S.Bjorkman, Chentsov E.L., V.G.Klochkova, N.Manset, et al.
was submitted to A&A on 2002 February 28.
Spectroscopic (resolving power R=60000) and
spectropolarimetric (R=15000) observations of the northern lobe
of the Egg nebula (AFGL2688) were performed at the 6-meter
telescope. Recent results published by Klochkova et al.(2000,
Astronomy Letters) confirmed the post-AGB evolutionary
state for the central star of this object.
The combination of spectroscopy and spectropolarimetry permits
us to separate optical spectral components formed in the
stellar atmosphere from those formed in the nebula. We showed
that the approximation of single scattering of optical radiation
is valid within the nebula. The optical spectrum of the nebula
contains emission components of the resonance sodium doublet
NaI D1&2, emission in H alpha, and emission bands of the C2
molecule. We showed that the nebula is optically thick in the
lines of the sodium doublet. A system of absorptions found
in the resonance sodium line confirms a continuation of the
matter outflow from the star. We resolved the rotational
structure of the emission bands of the Swan system of the C2
molecule. Our analysis of both the rotational spectrum and
vibrational-rotational transitions of the C2 molecule confirms
a hypothesis about the resonance fluorescence as their exciting
mechanism, which was proposed earlier by Klochkova et al. (2000).
A macroturbulence velocity in the atmosphere of the central star
was estimated. Radial velocities were measured using spectral
details formed both in the photosphere of the supergiant and
inside the lobe. An analysis of the optical data was carried out
in combination with published results based on the radio- and
IR-regions. We critically considered models suggested for the
nebula AFGL2688. It should be noted that high resolution
spectropolarimetry for such a faint object (V>14.5mag) was
obtained for the firts time.
The paper "Nebula AFGL2688: spectroscopy and spectropolarimetry
with high spectral resolution", by by V.G.Klochkova,
V.E.Panchuk and M.V.Yushkin, will be submitted to Astronomy
The processing of the results of spectroscopic monitoring of
the LBV object HD168607 is completed. Between 1992 and 2001 we
obtained 11 high-resolution spectra using CCD-echelle spectrometers
of the 6-m telescope of SAO RAS from 1992 through 2001.
HD168607 is a unique hypergiant that can be a key object in our
understanding of the LBV phenomenon. Its photometric behaviour
shows evidence of both pulsations in the photosphere and
"pseudo-photospheric" processes in its wind. We have revealed
the spectroscopic manifestations of both these processes.
The absorption lines of HeI, light ions, and FeII lines
of high excitation indicate the variable velocity gradient in
the photosphere, while variable multicomponent PCyg profiles of
hydrogen and FeII lines of low excitation give valuable
information about the variable and non-spherical wind. This
gives an additional argument in favour of adding HD168607 to the
LBV group. However, the important signatures of an LBV denoted by
an optical nebula and IR excess have not been discovered in this
object yet. We hope to understand the nature of HD168607 by means
of line profile modeling and of a direct comparison of its
spectrum with the spectra of the recognized LBVs of relatively low
luminosity, such as HR Car, R40, HD160529. (The paper by
Miroshnichenko A. and Chentsov E. is now under preparation).
A new joint paper by A.S.Miroshnichenko, K.S.Bjorkman,
Chentsov E.L., V.G.Klochkova, et al. ``The Luminouis B[e] Binary
AS 381'' was published in A&A (v.383, p.171, 2002). In this paper
we reported our finding of the first B[e] binary supergiant in the
Development of the new spectropolarimeter for the prime
focus of the 6-m telescope was continued during the last
quarter. Aspects of the work during this time include: a
specification for manufacturing of mechanical units to be
incorporated in a prime focus spectropolarimeter. This work
will be paid as a subcontract (Panchuk V.).