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1.
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
2.
It is generally believed that the only known reaction in whichC
p
violation definitely occurs is in the decay of the long-lived neutralK-mesonK
L
+–,K
L
00, andK
L
e
±±
v (Christensonet al., 1964: Sivaram, 1982). No attempt has been made to studyC
p
violation outside theK-system for quite a long time. Recently,C
p
violation effects have been reported in the hyperon decays through the reaction
(Bassompierre, 1990) with asymmetry at the level of 10–3 to 10–4.In this paper we examine the possible implications of hyperon decays asymmetry in some cosmic-ray sources. We identify cosmic-ray sources where such decays can occur. The signatures for measuring these asymmetries in both the laboratory and cosmic-ray sources are examined.It is found that there is a correlation between these signatures. We conclude that hyperon decays contribute significantly toC
p
violation observed in cosmic-ray sources. 相似文献
3.
J. E. Lancaster 《Celestial Mechanics and Dynamical Astronomy》1970,2(4):481-493
Analytical techniques are employed to demonstrate certain invariant properties of families of moon-to-earth trajectories. The analytical expressions which demonstrate these properties have been derived from an earlier analytical solution of the restricted three-body problem which was developed by the method of matched asymptotic expansions. These expressions are given explicitly to orderµ
1/2 where is the dimensionless mass of the moon. It is also shown that the inclusion of higher order corrections does not affect the nature of the invariant properties but only increases the accuracy of the analytic expressions.The results are compared with the work of Hoelker, Braud, and Herring who first discovered invariant properties of earth-to-moon trajectories by exact numerical integration of the equations of motion. (Similar properties for moon-to-earth trajectories follow from the principle of reflection). In each instance the analytical expressions result in properties which are equivalent, to orderµ
1/2, with those found by numerical integration. Some quantitative comparisons are presented which show the analytical expressions to be quite accurate for calculating particular geometrical characteristics.
Nomenclature
Orbital Elements near the Moon energy - angular momentum - semi-major axis - eccentricity - inclination - argument of node - argument of pericynthion Orbital Elements near the Earth h e energy - l e angular momentum - i inclination - argument of node - argument of perigee - t f time of flight Other symbols parameters used in matehing - U a function of the energy near the earth - a function of the angular momentum near the earth - r p perigee radius - perincynthion radius - radius at node near moon - true anomaly of node near moon - initial angle between node near moon and earth-moon line - a function ofU, , andi - earth phase angle - dimensionless mass of the moon - U 0, U1 U=U 0+U 1 - i 0, i1/2, i1 i=i 0+µ 1/2 i 1/2+µ i 1 - 0, 1/2, 1 = 0+µ 1/2 i 1/2+µ i 1 - p longitude of vertex line - n latitude of vertex line - R o ,S o ,N o functions ofU 0 and - a function ofU 0, and 相似文献4.
5.
H. Rovithis-Livaniou 《Astrophysics and Space Science》1977,52(2):271-306
The aim of the present paper is to find the eclipse perturbations, in the frequency-domain, of close eclipsing systems exhibiting partial eclipses.After a brief introduction, in Section 2 we shall deal with the evaluation of thea
n
(l)
integrals for partial eclipses and give them in terms ofa
0
0
,a
0
0
(of the associated -functions) and
integrals; while Section 3 gives the eclipse perturbations
arising from the tidal and rotational distortion of the two components. The
are given for uniformly bright discs (h=1) as well as for linear and quadratic limb-darkening (h=2 and 3, respectively).Finally, Section 4 gives a brief discussion of the results and the way in which they can be applied to practical cases. 相似文献
6.
7.
8.
The problem on linear waves in a radiating and scattering grey medium is studied using Whitham's method. Analysis of the basic equations distinguishes two limiting cases: the one is theequilibrium case in which the energy exchange between the gas and radiation plays an essential role, and the other is theScattering case in which the effect of energy exchange is negligible. A new type ofradiation acoustic wave with the speed
is found in the scattering case. The governing equations for linearized one-dimensional flow are reduced to one equation of radiative acoustics valid to order 1/c, and the criterion for the two limiting cases is derived from studying this equation. The harmonic solution is analytically studied to show that theeffective optical depth corresponding to the wavelength of perturbation gives the measure of the interaction between the gas and radiation. When eff1, the sound speeda
g
2
=P
g
/ and the propagating speed of radiative disturbancea
f
2
=fc
2 appear as the modified classical and radiation-induced modes respectively, wheref is the Eddington factor. When eff1, the isentropic sound speeda
s
2
=(P
g
+P
r
/ appears in the equilibrium case, and the radiation acoustic speeda
A
2
appears in the scattering case. The dispersion relation of the harmonic solution is numerically calculated. The result shows that the wave pattern depends critically on the ratio=P
g
/(P
g
+P
r
). When
, the speeda
S
anda
A
arise from the modified classical mode, and when
, they originate from the radiation-induced mode. 相似文献
9.
Ken G. Libbrecht 《Solar physics》1985,99(1-2):371-373
Techniques for generating large-order Y
l
m
(, ) are discussed. 相似文献
10.
Bogdan Wszolek Konrad Rudnicki Silvia Masi Paolo De Bernardis Antonio Salvi 《Astrophysics and Space Science》1989,152(1):29-34
We used theIRAS All Sky Maps in order to search for infrared emission in the direction of the Okroy Cloud (R.A.=12h50m, =22°). An enhancement of 100 m diffuse emission is evident in such a region, with an anomalous value of the ratioI
v (100 m)/A
v
; hydrogen 21 cm emission is also present with low radial speed, thus suggesting that the cloud could be a satellite of our Galaxy. 相似文献
11.
D. C. Schwank 《Astrophysics and Space Science》1976,43(2):459-468
Weight functions for the determination of the periods of linear adiabatic non-radial oscillations have been calculated in the same manner as Epstein's classic treatment of purely radial oscillations. Quadrupole (l=2) oscillations for thef and lower orderp andg-modes were considered. One group of static models were polytropes in the range 1.0n4.0 with
; thus included were configurations that were convectively stable, unstable and neutrally stable throughout. Another group consisted ofn=3.0 polytropes with convective shells or convective cores; 1 was set at different values in each region in order to produce stability (
) or instability (
). The weight function provides a pictorial means for assessing the relative importance of each region of a given static model with respect to generating a given non-radial mode. 相似文献
12.
We present a set of cylindrically-symmetric force-free magnetic fields with non-constant scalar function scalar. We found that the kink instability of the fields can be suppressed by reducing the length of the flux tube. By using the pressure profile in coronal magnetic loops obtained on the basis of the observational data, and by neglecting the effect of gravity, these force-free fields ars modified to non-force-free ones. For the plasma of finite conductivity the time and space dependent magnetic fields are obtained, and the ohmic dissipation per unit volume per second is calculated. For the magnetic fields, presented in the investigation, it is also found that, due to the large electrical conductivity of the plasma, the ohmic dissipation is negligable in comparison to the conduction and the radiation loss. Hence, for the energy equilibrium in a coronal loop, the contribution of ohmic dissipation is insignificant. 相似文献
13.
Klaus Becker 《Celestial Mechanics and Dynamical Astronomy》1974,9(2):269-289
Zusammenfassung Es wird gezeigt, daß die unter der Einwirkung einer Momentenimpulsserie entstehende Bewegung eines rotierenden Flugkörpers mit Nutationsdämpfung sich vollständig einem regelmäßigen Polygon entnehmen läßt, das durch das Trägheitsmomentenverhältnis, den Integralwert eines Einzelimpulses, den Drall und eine die Dämpfung charakterisierende KonstanteK
0 bestimmt ist.Die Bewegung setzt sich aus logarithmischen Spiralen zusammen, derenn-ten Anfangsradius man erhält, indem man den Teilungspunkt des im VerhältnisK
0:1 geteilten (n–1)-ten Radius mit der (n+1)-ten Polygonecke verbindet.Es wird bewiesen, daß das Konstruktionsnetz zu einem im äußeren Polygon liegenden ähnlichen inneren Polygon konvergiert, das gegenüber ersterem gedreht ist.Einfache Beziehungen zur Bewegungsbestimmung mit dem Polygonschema werden für Pulsfrequenzen angegeben, die ganzzahlige Vielfache oder Bruchteile der Spinfrequenz sind.
Symbole 1-2-3 Achsen des flugkörperfesten Koordinatensystems - a,b,c Hilfsgrößen zur Bestimmung der Iterationsgrößen - E i i-te Polygonecke - H Drall des Flugkörpers - K i Verhältnis deri-ten Drehzeigerlängen zu Beginn und am Ende eines Impulses - M Iterationsmatrix - Integralwert des Momentenimpulses - P 0 Äußeres Polygon - P 1 Spitze des Drehzeigersr 00e - P Drehpunkt des Drehzeigersr 00 - P Konvergierendes Polygon - P i Teilungspunkt des [i–1]-ten Zeigers - r 0i Drehzeiger aufgrund desi-ten Impulses allein - r 0ia Zeigerr 0i in Anfangslage - r 0ie Zeigerr 0i in Endlage - r i i-ter Summenzeiger - r ia Zeigerr i in Anfangslage - r ie Zeigerr i in Endlage - T Dauer einer Flugkörperumdrehung - t,t, Zeitargumente - x-y-z Achsen eines raumfesten Koordinatensystems - x i ,y i Iterationskoordinaten - n Phase desn-ten Radius gegenüber der anliegenden Polygonseite - Drehung des inneren Polygons gegenüber dem äußeren - Abklingkonstante - Phasenänderung des Drehzeigers innerhalb einer Flugkörperumdrehung - 0 Anteil der über 2 hinausgehenden Phasenänderung des Drehzeigers - 3 Trägheitsmoment um die Spinachse - 12 Trägheitsmoment um die Querachsen - Zahl der Ecken des Konstruktionspolygons - 1,2 Eigenwerte der Iterationsmatrix - Zahl der vollen Umläufe des Konstruktionspolygons - Fortbewegungsachse des Drallvektors - 0 Ausgangsphasenwinkel - i Phasenlage desi-ten Summenzeigers - x, y Drehwinkel nach Einzelimpuls fürt - , Funktionen der Iterationsgrößen - , Drehwinkel umx-bzw.y-Achse - Drehgeschwindigkeit der Spinachse um den Drallvektor - Fiktive Größen bei Pulsfrequenzen kleiner als Spinfrequenz - Fiktive Größen bei Pulsfrequenzen größer als Spinfrequenz 相似文献
It is shown that the motion of a spinning body with nutation damping due to a series of torque pulses can be completely derived from a regular polygon determined by the ratio of inertias, the integral of one pulse, the momentum and a constantK 0 characterizing damping.The motion is composed of spirals thenth initial radius of which is obtained by connecting the dividing point of the (n–1)th radius with the (n+1)th polygon corner. Each dividing point divides the respective radius in the ratioK 0:1. The net of construction lines converges into an inner polygon turned against the outer one and having the same shape.Simple rules are shown for the application of the scheme on pulse frequencies which are multiples or fractions of spin frequency.
Symbole 1-2-3 Achsen des flugkörperfesten Koordinatensystems - a,b,c Hilfsgrößen zur Bestimmung der Iterationsgrößen - E i i-te Polygonecke - H Drall des Flugkörpers - K i Verhältnis deri-ten Drehzeigerlängen zu Beginn und am Ende eines Impulses - M Iterationsmatrix - Integralwert des Momentenimpulses - P 0 Äußeres Polygon - P 1 Spitze des Drehzeigersr 00e - P Drehpunkt des Drehzeigersr 00 - P Konvergierendes Polygon - P i Teilungspunkt des [i–1]-ten Zeigers - r 0i Drehzeiger aufgrund desi-ten Impulses allein - r 0ia Zeigerr 0i in Anfangslage - r 0ie Zeigerr 0i in Endlage - r i i-ter Summenzeiger - r ia Zeigerr i in Anfangslage - r ie Zeigerr i in Endlage - T Dauer einer Flugkörperumdrehung - t,t, Zeitargumente - x-y-z Achsen eines raumfesten Koordinatensystems - x i ,y i Iterationskoordinaten - n Phase desn-ten Radius gegenüber der anliegenden Polygonseite - Drehung des inneren Polygons gegenüber dem äußeren - Abklingkonstante - Phasenänderung des Drehzeigers innerhalb einer Flugkörperumdrehung - 0 Anteil der über 2 hinausgehenden Phasenänderung des Drehzeigers - 3 Trägheitsmoment um die Spinachse - 12 Trägheitsmoment um die Querachsen - Zahl der Ecken des Konstruktionspolygons - 1,2 Eigenwerte der Iterationsmatrix - Zahl der vollen Umläufe des Konstruktionspolygons - Fortbewegungsachse des Drallvektors - 0 Ausgangsphasenwinkel - i Phasenlage desi-ten Summenzeigers - x, y Drehwinkel nach Einzelimpuls fürt - , Funktionen der Iterationsgrößen - , Drehwinkel umx-bzw.y-Achse - Drehgeschwindigkeit der Spinachse um den Drallvektor - Fiktive Größen bei Pulsfrequenzen kleiner als Spinfrequenz - Fiktive Größen bei Pulsfrequenzen größer als Spinfrequenz 相似文献
14.
E. R. Lancaster 《Celestial Mechanics and Dynamical Astronomy》1970,2(1):60-63
Approximation formulas are found for
and
, wherex(t) satisfies
,x(0)=x
0,x(1)=x
1. The results are applied to an example of two-body motion. 相似文献
15.
In the course of observations of the LMC with the Glazar space telescope it was found that the star HD 269665 is unusually bright at 1640 A:m
1640 = 5
.
m
± 0
.
m
1,m
1640 –V = –6
.
m
2. 相似文献
16.
The adiabatic theory of interaction between high and low frequency waves has been studied for the case of electron plasma oscillations and ion acoustic waves and the results are applied to the solar wind. The modified dispersion relation for ion acoustic waves has been derived, taking a Gaussian distribution for plasmons. Two limiting cases of the spectrum are studied. For a broad spectrum, the plasma turbulence has a destabilising effect by introducing a growth rate denoted by turbulence, which is positive for k
0 > (m
e/
m
i
)1/2
De
–1
, k
0 being the central wave numger of the spectrum,
De the electron Debye length. Also, even for v
d(drift velocity between electrons and ions) < c
s, we arrive at unstable ion acoustic modes. For narrow spectrum, the plasma turbulence has a stabilising effect. 相似文献
17.
We develop an approach to deriving the three-dimensional non-force-free coronal magnetic field from vector magnetograms. Based
on the principle of minimum dissipation rate, a general non-force-free magnetic field is expressed as the superposition of
one potential field and two constant-α (linear) force-free fields. Each is extrapolated from its bottom boundary data, providing the normal component only. The
constant-α parameters are distinct and determined by minimizing the deviations between the numerically computed and measured transverse
magnetic field at the bottom boundary. The boundary conditions required are at least two layers of vector magnetograms, one
at the photospheric level and the other at the chromospheric level, presumably. We apply our approach to a few analytic test
cases, especially to two nonlinear force-free cases examined by Schrijver et al. (Solar Phys.
235, 161, 2006). We find that for one case with small α parameters, the quantitative measures of the quality of our result are better than the median values of those from a set
of nonlinear force-free methods. The reconstructed magnetic-field configuration is valid up to a vertical height of the transverse
scale. For the other cases, the results remain valid to a lower vertical height owing to the limitations of the linear force-free-field
solver. Because our method is based on the fast-Fourier-transform algorithm, it is much faster and easy to implement. We discuss
the potential usefulness of our method and its limitations. 相似文献
18.
Boris Garfinkel 《Celestial Mechanics and Dynamical Astronomy》1983,30(4):373-383
In a previous publication (1977) the author has constructed a family () of long-periodic orbits in the Trojan case of the restricted problems of three bodies. Here he constructs the domain of the analytical solution of the problem of the motion, excluding the vicinity of thecritical divisor which vanishes at the exact commensurability of the natural frequencies 1 and 2. In terms of thecritical masses mj(2), or the associatedcritical energies
j
2
(m), is the intersection of the intervals ofshallow resonance, of the form. Inasmuch as the intervals |2–
j
2
|<j ofdeep resonance aredisjoint, it follows that (1) the disjointed family () embraces the tadpole branch, 021, lying in: and (2) despite the clustering of
j
2
(m) atj=, the family () includes, for 2=1, an asymptoticseparatrix that terminates the branch in the vicinity of the Lagrangian pointL
3.In a similar manner, the family () can be extended to the horseshoe branch 1<2
2
2
. 相似文献
19.
We derive upper limits to the radiation temperaturesT
t(k) for emission near the fundamental and second harmonic of the electron plasma frequency in terms of the effective temperature for plasma wavesT
l(k). We findT
t(k)(c/(3)1/2
V
e)3
T
l(k) for emission near the fundamental which differs from the result of Melrose (1970b) by the factor in parentheses. This factor can exceed 4×104 in some plasmas. The conditions under which this limit could be reached are delinated. For emission near the second harmonicT
t(k)T
l(k) since the absorption coefficient in this case can only be positive.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
20.
Generation of acoustic and gravity waves by turbulence in an isothermal stratified atmosphere 总被引：1，自引：0，他引：1
Robert F. Stein 《Solar physics》1967,2(4):385-432
Lighthill's method of calculating the aerodynamic emission of sound waves in a homogeneous atmosphere is extended to calculate the acoustic and gravity-wave emission by turbulent motions in a stratified atmosphere. The acoustic power output is P
ac 103
o
u
o
3
/l
o
M
5 ergs/cm3 sec, and the upward gravity wave flux is F
zgr 102
o
U
o
3
/l
o (l
o ergs/cm3 sec. Here u
0 is the turbulence velocity scale, l
0 is its length scale, and H the scale height at the atmosphere. M = u
0/c
0 is the Mach number of the turbulence. The acoustic power output is proportional to the maximum value of the turbulence spectrum, and inversely to its rate of falloff at high frequencies. The stratification cuts off the acoustic emission at low Mach numbers. The gravity emission occurs near the critical angle to the vertical
c = cos–1
/
2, where
2
2
= ( - 1)/
2 (c
0/H), and at very short wavelengths. It is proportional to the large wave number tail of the turbulence spectrum. On the sun, gravity-wave emission is much more efficient than acoustic, but can occur only from turbulent motions in stable regions, whereas acoustic waves are produced by turbulence in the convection zone. 相似文献