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V. P. Arkhipova N. P. Ikonnikova G. V. Komissarova V. F. Esipov 《Astronomy Letters》2006,32(9):594-603
We present the results of our photoelectric observations of HD 51585 (OY Gem), a B[e] star with an infrared excess and a candidate for protoplanetary nebulae, obtained with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute in 1992–2005. The star exhibited rapid irregular brightness variations with amplitudes from We present the results of our photoelectric observations of HD 51585 (OY Gem), a B[e] star with an infrared excess and a candidate
for protoplanetary nebulae, obtained with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute
in 1992–2005. The star exhibited rapid irregular brightness variations with amplitudes from
in the V band to
in U band within the observing season as well as slow systematic variations with amplitudes from
in the V band to
in the U band and with a quasi-period of ∼2800 days. The B-V color index varied within
and did not follow the slow systematic brightness variations, while U-B correlated with the U brightness and varied between
at maximum light and
at minimum light. Our low-resolution spectroscopy performed in 1994–2005 has revealed significant variability of the Balmer
and Paschen hydrogen emission lines as well as the He I and O I lines. Equivalent widths are given for the H I, He I, O I,
and Fe II lines; a correlation has been found between the star’s photometric variability and the hydrogen line intensities.
Our joint analysis of the photometric and spectroscopic data suggests that variations in a strong stellar wind are responsible
for the variability of the star.
Original Russian Text ? V.P. Arkhipova, N.P. Ikonnikova, G. V. Komissarova, V. F. Esipo, 2006, published in Pis’ma v Astronomicheskiĭ
Zhurnal, 2006, Vol. 32, No. 9, pp. 662–671. 相似文献
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Stanisław P. Kasperczuk 《Celestial Mechanics and Dynamical Astronomy》2000,76(4):215-227
In a recent paper Ballersteros and Ragnisco (1998) have proposed a new method of constructing integrable Hamiltonian systems.
A new class of integrable systems may be devised using the following sequence:
, where A is a Lie algebra
is a Lie–Poisson structure on R
3, C is a Casimir for
is a reduced Poisson bracket and (A, ▵) is a bialgebra. We study the relation between a Lie-Poisson stucture Λ and a reduced Poisson bracket
, which is a key element in using the Lie algebra A to constructing this sequence. New examples of Lie algebras and their
related integrable Hamiltonian systems are given.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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A linear correlation between the ratio of the[CII( $^{\text{2}}$ P A linear correlation between the ratio of the[CII(
P
→
P
)] line intensity to the [
CO(J:1 →0)] line emission, I
/I
and the
equivalent width (EW) is found, over the range 2–71 ? in
EW, for a sample of 21late-Type= galaxies. The latter is comprised of an optically selected sample of 12 normal Virgo Cluster
spiral galaxies with [CII] detections obtained by us with ISOLWS, plus nine late-Type= galaxies with higher star formation
rates (SFRs), for which [CII] data and, especially,
EW data are available in the literature. As a result we infer I
/I
to be a reliable tracer of the current mass-normalized global SFR for non-starburst spiral galaxies. Moreover, the ratio
of the [CII] line to the total far-infrared (FIR) continuum intensity, I
/I
, is found to decrease from ∼0.5% to ∼0.1% with decreasing SFR which we propose is due to a `[CII]-quiet' component of I
from dust heated by the general interstellar radiation field (ISRF). The more `quiescent' galaxies in the sample have values
of I
/I
different from those observed in `compact' Galactic interstellar regions. Their [CII]-emission is interpreted to be dominated
by diffuse regions of the interstellar medium (ISM). For normal `star-forming' galaxies the diffuse component of the [CII]
emission is estimated to account for at least 50% of the total.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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1998 UBV photometry of short period eclipsing binary ST Aquarii have been presented. The photometric solution obtained from light
curve analysis by the method of differential corrections indicates that the system can be classified as a near contact binary.
Derived value for the ratio of radii
shows that both components cannot be considered to be Main-Sequence, but they are probably evolved from M.S.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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The photometric elements of the Algol type binary TT Hydrae derived by the authors from theirUBV observations during 1973–77 have been combined with the spectroscopic elements given by Sanford (1937) and Sahade and Cesco
(1946) to obtain the absolute dimensions of the system. It is found that the spectroscopic orbital elements given by Sanford
represent the evolutionary status of the secondary component better than those of Sahade and Cesco. The primary appears to
be an Al v main sequence star of mass
and radius ∼2.3R
⊙. The secondary fills its Roche lobe; it can be represented by a K0iii star of mass
and radius ∼6.0R
⊙. Better spectroscopic data are needed for confirmation of these results. 相似文献
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I. Stellmacher 《Celestial Mechanics and Dynamical Astronomy》1999,75(3):185-200
The motion of Hyperion is an almost perfect application of second kind and second genius orbit, according to Poincaré’s classification.
In order to construct such an orbit, we suppose that Titan’s motion is an elliptical one and that the observed frequencies
are such that 4n
H−3n
T+3n
ω=0, where n
H, n
T are the mean motions of Hyperion and Titan, n
ω is the rate of rotation of Hyperion’s pericenter. We admit that the observed motion of Hyperion is a
periodic motion
such as
. Then,
.N
H, N
T, k∈ N
+. With that hypothesis we show that Hyperion’s orbit tends to a particular periodic solution among the periodic solutions
of the Keplerian problem, when Titan’s mass tends to zero. The condition of periodicity allows us to construct this orbit
which represents the real motion with a very good approximation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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V. P. Arkhipova V. G. Klochkova E. L. Chentsov V. F. Esipov N. P. Ikonnikova G. V. Komissarova 《Astronomy Letters》2006,32(10):661-670
We present the results of spectroscopic and photometric observations for the B star StHα62 with an IR excess, a post-AGB candidate identified with the IR source IRAS 07171+1823. High-resolution spectroscopy has allowed the λ4330–7340 Å spectrum of the star to be identified: it contains absorption lines of an early B star and emission lines of a gaseous shell. The residual line intensities have been measured. The heliocentric radial velocities measured from absorption lines of the star and emission lines of the shell are 〈V r 〉 = +45 ± 1 and +52 ± 1 km s?1, respectively. The line-of-sight velocities of gas-dust clouds determined from the interstellar Na I lines are 12 and 33 km s?1. The He I λ5876 Å line exhibits a P Cyg profile, which is indicative of an ongoing mass loss by the star. The expansion velocity of the outer shell estimated from forbidden lines is 12–13 km s?1. Quantitative classification gives the spectral type B0.51 for the star. The parameters of the gaseous shell have been determined: N e = 3.1 × 103 cm?3 and T e ～ 21 000 K. Over 4 years of its observations, the star showed rapid irregular light variations with the amplitudes ΔV = We present the results of spectroscopic and photometric observations for the B star StHα62 with an IR excess, a post-AGB candidate
identified with the IR source IRAS 07171+1823. High-resolution spectroscopy has allowed the λ4330–7340 ? spectrum of the star
to be identified: it contains absorption lines of an early B star and emission lines of a gaseous shell. The residual line
intensities have been measured. The heliocentric radial velocities measured from absorption lines of the star and emission
lines of the shell are 〈V
r
〉 = +45 ± 1 and +52 ± 1 km s−1, respectively. The line-of-sight velocities of gas-dust clouds determined from the interstellar Na I lines are 12 and 33
km s−1. The He I λ5876 ? line exhibits a P Cyg profile, which is indicative of an ongoing mass loss by the star. The expansion velocity
of the outer shell estimated from forbidden lines is 12–13 km s−1. Quantitative classification gives the spectral type B0.51 for the star. The parameters of the gaseous shell have been determined:
N
e
= 3.1 × 103 cm−3 and T
e
∼ 21 000 K. Over 4 years of its observations, the star showed rapid irregular light variations with the amplitudes ΔV =
, ΔB =
, and ΔU =
and no color-magnitude correlation. We estimate the total extinction for the star from our photometric observations as A
v
=
. Near-IR observations have revealed dust radiation with a temperature of ∼1300 K. We estimate the distance to StHα62 to be
r = 5.2 ± 1.2 kpc by assuming that the star is a low-mass (M = 0.55 ± 0.05 M
⊙) protoplanetary nebula.
Original Russian Text ? V.P. Arkhipova, V.G. Klochkova, E.L. Chentsov, V.F. Esipov, N.P. Ikonnikova, G.V. Komissarova, 2006,
published in Pis’ma v Astronomicheskiĭ Zhurnal, 2006, Vol. 32, No. 10, pp. 737–747. 相似文献