Publications of the Astronomical Society of the Pacific

Grygar, 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

Sakurai, 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

Noonan, 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

Noonan, Thomas W.

doi: 10.1086/129060pmid: N/A

Page's work on double galaxies is extended to the ratio of mass to 10-O.6M, where M is the absolute magnitude. The resulting mean cosmic density to a distance of order 102 Mpc is (1.6 i 1.6) x 3forH = . Key words: cosmic density - double galaxies

Noonan, 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

Noonan, 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

Landolt, Arlo U.

doi: 10.1086/129063pmid: N/A

Recent UBV photoelectric observations of the southem cepheids Car, AC Cm, and ST Pup are discussed. New light elements are given for AC Cm and ST Pup. Key words: UBV photometry - cepheids - variable stars - light curves

Preston, 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