The Magnitudes of the Thirty Brightest Stars in the North Polar Sequence

Abstract

view Abstract Citations (10) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Magnitudes of the Thirty Brightest Stars in the North Polar Sequence Stebbins, Joel ; Whitford, A. E. Abstract The magnitudes and colors of stars of the North Polar Sequence down to magnitude 11.6 have been measured with a photoelectric cell attached to the 6o-inch reflector. lie measured colors of these stars are in good agreement with the colors of the international system, and confirm the result of Seares that the polar region is one of moderate obscuration and selective absorption. Special treatment is given to the known variable Polaris; the phase and amplitude of the light-variation of this star agree well with the prediction from recent photoelectric measures by Meyer. The photoelectric magnitudes have the usual small accidental errors, and the scale has been tested over the range from magnitude 2.5 to 11.6. Laboratory measures of an artificial star, observations of stars with a neutral-shade glass, observations of the stars down to magnitude 9.2 with the is-inch telescope at Madison, and independent meas- ures of 13 stars with an ultraviolet cell on the 6o-inch, all agree in giving the same scale of magnitudes. There are serious differences between the photoelectric and the international photographic magnitudes, especially from the fifth to the ninth magnitude, where the two systems diverge by nearly o. 20 mag. The possibility that this divergence is due to strong hydrogen absorption is discussed by Seares in Mt. W. Contr., No. 587. Formulae are given for the reduction of photoelectric or photographic magnitudes to our suggested revision of the international scale Publication: The Astrophysical Journal Pub Date: April 1938 DOI: 10.1086/143924 Bibcode: 1938ApJ....87..237S full text sources ADS | Related Materials (1) Reprint: 1938CMWCI.586....1S