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81. The effect of mass removal on the dynamical evolution of a system of young stars and gas

Creator:
Verschueren, Werner and David, Marc
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics and newly born stars
Language:
Czech
Description:
The star formation process in a molecular cloud core is effectively halted when the newly born stars remove the remaining gas cloud out of the region. We present analytical and numerical calculations of the dynamical evolution of a young cluster, which we allow to deviate from or oscillate around exact Virial Equilibrium (V.E.), during slow and rapid gas removal. Our conclusion is that deviations from V.E. can influence the final dynamical state of the 'nakeď cluster significantly.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

82. The evershed flow in the solar photosphere, chromosphere and chromosphere-corona transition region

Creator:
Alissandrakis, C. E., Dialetis, D., Mein, P., Schmieder, B., and Simon, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics, sunspot regions, and evershed flow
Language:
Czech
Description:
We have studied the height dependent characteristics of the Evershed flow in the photosphere, chromosphere and chromosphere-corona transition region. We have used the Multichannel Subtractive Double Pass Spectrograph (MSDP) to obtain line of sight velocity maps in Hα, the Meudon magnetograph for mapping the photospheric velocity field and the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) spacecraft to obtain line of sight velocities in C IV, in sunspot regions. Our emphasis was on the large scale, quasi-stationary characteristics of the flow. In the photosphere the velocity is low above the umbra and shows a maximum above the penumbra. In addition to the reversal of the flow in the chromosphere both the characteristic scale of the flow and the velocity are larger; the velocity maximum is located outside the photospheric penumbra. In the chromosphere-corona transition region there is a clear tendency for a chromospheric-type Evershed effect with a predominantly horizontal flow. The velocity is greater than in the chromosphere, but the characteristic scale of the flow is about the same. In addition to the Evershed flow, C IV observations show upflows above the umbra with a velocity of about 15 km/sec.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

83. The LDE flares (1969-1990)

Creator:
Antalová, A. and Viktorínová, B.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics and LDE flares
Language:
Czech
Description:
The occurrence of LDE flares in the last three solar cycles has been investigated. Generally, in all the cycles considered, LDE flares mainly originated during a 6-year interval of the respective cycle (2 years before and 4 years after the cycle maximum). The highest LDE flare occurrence was observed in the ascending phase of the 22nd cycle (monthly mean number in 1989 - 32, in 1970 - 19 and in 1980 - 14 LDE (M-X) flares).
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

84. The long-range variability of annual precipitation in Prague - Klementinum in the period 1805-1951 and in relation to the solar activity

Creator:
Křivský, Ladislav
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics and solar activity
Language:
Czech
Description:
The condition of measurement of precipitation from the year 1805 up-to the present time are defined. On the vasis of an analysis of the conditions and by comparison with the neighbouring stations a whole series of annual percipitation is homogenized. The original values in the period 1805-1830 are reduced for 8.7 %, the period 1840-1905 zemains unchanged, the period 1906-1951 is reduced partly for 10 % (Hlaváč), partly for 15 %. For the statement of long-range variability of the annual precipitation the method of double-time integral of precipitation deviations was used. The curves thus gained show a long-range variation having a contraty course regarding the secular curve of solat activity (90-year-rhythm). The long-range relation of the variability of annual precipitation to the secular solar activity is expounded by the change of circulation (showing the width of the frontal zone). Further a close connection between the course of yearly precipitaton nd Ejgenson´s Index of Recurrency of Sunspots was found, which is evidently applicable for Central-Europe. Immediately after the maximum of Recurrency Index there is a characteristic decrease of precititation, closely following the minimum of Recurrency Index there is remarkable rise. On the ground of extrapolation of the acquired secular curves of precipitation and on the ground of physically justified correlation with long-range solar activity, a prognosis of the course of the annual precipitation up to the year 2000 is defined. At present the long-range course of precipitaton shows the minimum, in the years 1970-1990 the precipitation should reach the secular maximum.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

85. The outline of the theory of distribution and occurence of sunspots on the solar disc

Creator:
Kopecký, Miloslav
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics, sunspot groups, and solar disc
Language:
Czech
Description:
(Rezjume) Cel'ju nastojaščego truda javljajetsja obobščenije svedenij iz teorii raspredelenija i pojavlenija solnečnych pjaten na diske Solnca. V etoj svojej rabote avtor ischodit kak iz rjada trudov drugich avtorov, tak i iz svoich sobstvennych trudov, pomeščennych v raznych žurnalach, dopolnjaja eti trudy nekotorymi novymi svedenijami. Eta rabota javljajetsja sozdat' obobščenoje predstavlenije o teorii raspredelenija i pojavlenija solnečnich pjaten na diske Solnca. Nastojaščaja rabota, odnako ne zanimajetsja osveščenijem voprosov etoj teorii s obščej točki zrenija, tak kak boleje obščaja teorija ne byla do sich por v soveršenstve razrabotana. Eta teorija osnovljajetsja na opredelinii uproščennych predpoloženij, iz kotorych samymi prostymi javljajutsja sledujuščije: 1) Vse solnečnyje pjatna pojavljajutsja tol'ko na ekvatore, kotoryj vsegda prochodit po seredine diska Solnca, t. e. čto "korolevskij pojas" pojavljenija solnečnych pjaten možno sebe predstavit' v vide cilindra, na ktoryj smotrim v napravlenii normali i jego poverchnosti. 2) V dejstvitel'nosti predpoložim, čto grupy solnečnych pjaten sostavljajutsja iz odnogo pjatna okrugloj formy. Eti predloženija pozvoljajut nam sozdat' vozmožno polnuju osnovnuju teoriju raspredelenija i pojavlenija pjaten, kotoraja neobchodima dlja ocenki rezul'tatov raznych statistik pjaten i iz kotoroj možno ischodit' dlja sozdanija boleje obščej teorii. Nastojaščaja rabota zanimajetsja prežde vsego sledujuščimi voprosami: opredelenijem osnovnych otnošenij i funkcij, umen'šenijem količestva pjaten v napravlenii k kraju solnečnogo diska, količestvom pojavšichsja i isčeznuvšich pjaten na raznych rasstojanijach ot central'nogo meridiana, podsčetom količestva voznikšich grupp na vsem Solnce i srednej prodolžitel'nosti ich žizni i značenijem etich veličin dlja issledovanija periodičnosti solnečnych pjaten.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

87. The simulation of the bimodal IMF

Creator:
Wolf, M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics, massive molecular clouds, and fragmentation
Language:
Czech
Description:
The hierarchical fragmentation of a molecular cloud is modelled as a random process by the Monte Carlo method. It is proposed that the IMF for stár formation is bimodal. The probability of the fragmentation in each mode is a function of the initial cloud mass and defined critical mass, which can be derived from the surface density and temperature of cloud. The modelled IMF is compared with the empirically determined function and the best fit was found for critical masses of 0.3 M^ for low-mass mode and 2.0 M„ for high-mass mode of star formation.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

88. The starformation and structure of the NGC I275 galaxy circumnuclear region

Creator:
Pronik, I. and Metik, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics and Seyfert galaxies
Language:
Czech
Description:
The Seyfert galaxy NGC I275 circumnuclear region was investigated using spectro- and color photometry which permited us to reveal the region of active starformation near desils, located 3" North-West and 7" North-East from the NGC I275 galaxy nucleus. The mass of these regions HII zones is about 10^6 - 10^7.* and * Abstrakt obsahuje neidentifikovatelný (ručně psaný) symbol.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

89. The variability of the runaway star 53 Arietis

Creator:
Sterken, C.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics, spectrographic observations, and star 53 Arietis
Language:
Czech
Description:
From photometric and spectrographic observations of the runaway star 53 Ari we confirm that the star did noat exhibit detectable light- and radial velocity variations. The star is definitely not a beta Cephei star.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

90. The variation of the frontal zone during the year in the area of the Atlantic and Europe and in relation to the solar activity

Creator:
Gregor, .Z. and Křivský, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
astrophysics and solar activity
Language:
Czech
Description:
I. The mean state of circulation in some of the months can be demonstrated by the mean position of the frontal zone. From the position of the frontal zone we can determine if the zonal or meridional circulation prevails, and in which way it will change during the year II. The long-range variation of the mean frontal zone in relation to solar activity expressed by Ejgenson s Index of Recurrency of Sunspots A is determined. The effect ascertained is especially significant in January. The results in maps show the deviations of frequencies of the zones from the mean state, partly in the years of minima, partly in the years of maxima of the recurrency of sunspots.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public