摘要:

AbstractWe present CCDVICphotometry in a field 1.9 − 1.3 square arcmin and positioned about 3 arcmin north‐east of the centre of M82. More than 100 stars have been identified and measured above the photometric limitsV= 23m.5,I= 22m. Most of the objects fainter thanV≈︁ 20mshould be members of M82 as expected from the statistics of foreground stars.Starlike as well as 2–3 somewhat diffuse objects ‐ candidates of globular clusters ‐ preferentially occupy yellow colours in the colour‐magnitude diagram; extreme blue and red objects are missing. The colour‐magnitude diagram indicates continuing star formation in this part of the disk. The absence of blue stars is caused by reddening; no convincing explanation is found for the missing red supergiants. Young stars are distributed throughout the whole field, the youngest being concentrated in associations at the SW edge of the field.To cope with the very irregular background created by the galaxy' s main body and with the low contrast of many of the stars against this background, a modified photometric method is introduced in which the background is estimated using the intensities in a ring drawn very tightly around the star in the wings of the poin

ISSN:0004-6337    

DOI:10.1002/asna.2113170402

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractWe present the position and references (if available) of all the galaxies of the Shakhbazian survey being the largest survey of compact galaxy groups. For the estimation of the coordinates the Digitized Sky Survey was used. This paper contains the data of 48 Shakhbazian groups north of δ>+ 2deg;30' (Shkh 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 25, 26, 28, 29, 31, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)

ISSN:0004-6337    

DOI:10.1002/asna.2113170403

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractMeasurements of the fluxtube field strengthBand filling α in solar flares, active regions and faculae have been analyzed. To estimate the values ofB, StokesVpeak separations of the Fe I 5247 Å and Fe I 5250 Å lines have been used. It was found that the value ofBin an In‐flare (˜ 1.1 kG) was slightly smaller than that in faculae (˜ 1.3 kG) and a non‐flare active region (˜ 1.4kG). On the other hand, in a more power 2b‐flare the value ofBwas in the range from. 1.1 kG (the start of the flare) to 1.55kG. (during the peak). Thus the values of the field strength of flares somewhat differ from those both of faculae and active regions. The magnetic filling factor is approximately equal in flares (0.2‐0.40) and active regions (0.3) but several times larger as compared

ISSN:0004-6337    

DOI:10.1002/asna.2113170404

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractWe have used data from five neutron monitor stations with primary rigidity (Rm) ranging from 16 GeV to 33 GeV to study the diurnal variations of cosmic rays over the period: 1965–1986 covering one 22‐year solar magnetic cycle. The heliosphere interplanetary magnetic field (IMF) and plasma hourly measurements taken near Earth orbit, by a variety of spacecraft, are also used to compare with the results of solar diurnal variation. The local time of maximum of solar diurnal diurnal variations displays a 22‐year cycle due to the solar polar magnetic field polarities. In general, the annual mean of solar diurnal amplitudes, magnitude of IMF and plasma parameters are found to show separte solar cycle variations. Moreover, during the declining period of the twenty and twenty‐ne solar cycles, large solar diurnal amplitudes are observed which associated with high values of solar wind speed, plasma temperature and interplanetary magnetic field magni

ISSN:0004-6337    

DOI:10.1002/asna.2113170405

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractVariations of annual and semiannual oscillations in rotation parameters have been investigated on the basis of length‐f‐ay(LOD) as well as atmospheric‐ngular‐omemtum (AAM) series. These oscillations were determined using band‐ass filters. In order to show the character of variations of seaasonal oscillations, amplitudes, phases and periods were computed by a least‐quares adjustment with the method of modified harmonic analysis at quarterly intervals. In addition, the seasonal imbalances in LOD and AAM budgets were determined and analysed in a similar way. These discrepancies were corrected for tidally excited effects. The non‐tmospheric oscillations without the annual tide effect Sa and the semiannual tide effect Ssa have variable amplitudes between 0.02

ISSN:0004-6337    

DOI:10.1002/asna.2113170406

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractWe propose a small interferometer on a minisatellite, named DIVA (Deutsches Interferometer für Vielkanalphotometrie und Astrometrie), to perform astrometric and photometric observations of at least one million stars. It would exceed the performance of Hipparcos in all important parameters. With a possible launch in 2002 DIVA would provide for all stars brighter thanV= 10m5–parallaxes better than 0.8 milliarcseconds (mas) –proper motions better than 2 mas/y–broad‐band photometry with a tyupical accuracy of 0.002 mag –multi‐channel intermediate‐band photometry with a typical accuracy of 0.01 to 0.02 mag For the 100 000 stars observed by Hipparcos, proper motions with a typical accuracy of 0.1 to 0.2 mas/y and parallaxes of 0.3 to 0.5 mas can be obtained in combination with the Hipparcos results. The scientific potential of this mission and a possible layout of its optical system are described

ISSN:0004-6337    

DOI:10.1002/asna.2113170407

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2113170401

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY