LOW-DISPERSION SPECTRA OF NOVA SERPENTIS 1970Andersen, Per H.; Borra, Ermanno F.; Dubas, Orest V.
doi: 10.1086/129055pmid: N/A
A discussion of the spectral development of Nova Serpentis 1970 is given from the early decline to the nebular stage. The spectral changes are correlated with the light-curve. Velocities are given for the absorption systems during the early decline from 40 AImm and 60 AImm plates, while plates at 320 A/mm have been used only for discussing spectral changes qualitatively. Key words: novae - novae spectra - Nova Seipentis 1970
THE TRANSITION STAGE SPECTRUM OF NOVA SERPENTIS 1970Grygar, J.; Smoliński, J.; Hutchings, J. B.
doi: 10.1086/129057pmid: N/A
Four blue spectrograms, dispersion 15 A'/mm, were obtained in the advanced transition phase of Nova Serpentis 1970 7 below maximum light. The identifications and radial velocities for the emission peaks and samples of intensity tracings around Hfi and H7 are presented. The lines display saddle-shaped profiles, with the blue emission components generally much stronger than the red ones. The velocity separation of both peaks remains constant ( 918 km/s) while the whole structure of the lines was apparently shifted to the red some 50 km/s between JD 2440730 and JD 2440751. In the same time the [0 iii] lines became the most prominent features in the blue spectrum. Key worjs: novae - novae spectra - radiA velocities - Nova Serpentis 1970
ON THE ACCELERATION OF RELATIVISTIC ELECTRONS IN SOLAR PROTON FLARESSakurai, Kunitomo
doi: 10.1086/129058pmid: N/A
The acceleration mechanism of relativistic electrons in solar flares is considered by taking into account the physical condition of accelerating regions such as plasma density and magnetic field intensity. For the electrons of the kinetic energy range 10 MeV, it is shown that the Fermi acceleration is more effective than the betatron acceleration. The most plausible values of the plasma number density and the strength of sunspot magnetic fields in the accelerating regions are estimated to be cm-3 and gauss, respectively. This suggests that the accelerating regions are located somewhere above the Ha-flare regions. The accelerating regions may be identified with the triggering regions of solar flares where 8irPkin/B2 << 1 (Fkin: kinetic plasma pressure; B: sunspOt magnetic field intensity) and so they approximately satisf the force-free condition as regards magnetic field configuration. The accelerated electrons and their relation to the emission of type IV radio bursts are briefly discussed. Key words: solar proton flares - relativistic electrons
THE MEAN COSMIC DENSITY FROM GALAXY COUNTS AND MASS DATANoonan, Thomas W.
doi: 10.1086/129059pmid: N/A
Use of the mean ratio of mass to 10-O.6M, where M is the absolute magnitude, instead of the ratio of mass to 10-O.4M (luminosity) allows determination of the mean cosmic density from galaxy counts and galaxy masses alone, without the need for luminosity flinctions. Available data indicate a mean density of 2 to 5 X 10- 1 g , for a Hubble constant of 100 km Mpc 1, to a distance of order 102 Mpc. The greatest uncertainty comes from galaxy masses and galaxy counts, rather than galactic absorption or abundances of galaxy types. Key words: cosmic density - mass-luminosity ratio - galaxy counts
THE MEAN COSMIC DENSITY BASED ON MASSES OF CLUSTERS OF GALAXIESNoonan, Thomas W.
doi: 10.1086/129061pmid: N/A
The mean ratio R of mass to total 10-O.6M, where M is absolute magnitude, for clusters of galaxies (particularly the Coma cluster) is derived and used to obtain the mean cosmic density based on the assumption that field galaxies have the same mean R as cluster galaxies (including the "unseen" mass). The result is p = (5 2) >c 10-30 g for H = . Key words: cosmic density - galaxies - clusters of galaxies
COSMOLOGICAL REDDENING OF FIELD GALAXIESNoonan, Thomas W.
doi: 10.1086/129062pmid: N/A
The reddening of field galaxies is equal to kz, where k is the linear coefficient in the Kcorrection (z) = kz, and z is the solution to the redshift-magnitude relation log z = 0.2m - 4.630, where m is the apparent magnitude as seen outside the Galaxy, Keorrected for the redshift z. This result holds out to un-K-corrected magnitude (pg). Key words: cosmological reddening - cosmological expansion - redshifts
HD 161227: A SCANDIUM-DEFICIENT F-TYPE STARPreston, George W.
doi: 10.1086/129064pmid: N/A
All lines of Sc ii are very weak in the spectrum of the FO II star HD 161227. If the luminosity assignment is correct, this star may be a post-main-sequence example of a hot Am star in which metallic-line characteristics are still detectable. Key words: metallic-line stars - scandium-deficient stars - HD 161227