The observed combination of neutral helium and hydrogen lines (and at comparable intensities) may be unique among white dwarf stars. The proper motion from Luyten and the Lowell Observatory is large enough to very nearly constrain the star to be degenerate, rather than a hot subdwarf the blue continuum indicates that it is the hottest of the known magnetic degenerate stars. It is argued that the period must be due to rotation, and an oblique rotator model with the rotation axis in the plane of the sky and at approx.24degree tilt angle to the magnetic axis is compatible with the available observations. The star in fact provides the first confirmation of the theoretical spectra of hydrogen and helium in such high fields, inaccessible to laboratory measurement. The detailed absorption spectrum is shown to fit Zeeman patterns of hydrogen and neutral helium in the presence of a more » mean homogeneous surface field varying slightly with the polarization period from 18 to 20 megagauss. Spectra obtained with the Lick Observatory scanner and the UCSD Digicon at Steward Observatory are presented. The mean longitudinal field at peak polarization is estimated to be 5 megagauss. The polarization observations show a variation that is sinusoidal with amplitude 0.3%, a mean of nearly zero, and a period of 2.2 hours an ephemeris is provided. The blue white dwarf suspect Feige 7 (=L795-7=GR 267) has been found to be magnetic with a rich optical spectrum and variable circular polarization. Since frequency and wavelength are inversely proportional, this is equivalent to saying that the frequency of the light is reduced towards the red part of the light spectrum, giving this phenomenon the name redshift.=. If applied to optical wavelengths, this manifests itself as a change in the colour of visible light as the wavelength of the light is increased toward the red part of the light spectrum.

There also exists a corresponding blueshift when electromagnetic radiation propagates from an area of a weaker gravitational field to an area of a stronger gravitational field. There is a corresponding reduction in energy when electromagnetic radiation is red-shifted, as given by Planck's relation, due to the electromagnetic radiation propagating in opposition to the gravitational gradient. As frequency is inverse of time, frequency of the electromagnetic radiation is reduced in an area of a higher gravitational potential. This is a direct result of Gravitational time dilation - as one moves away from a source of gravitational field, the rate at which time passess is increased relative to the case when one is near the source. In astrophysics, gravitational redshift or Einstein shift is the process by which electromagnetic radiation originating from a source that is in gravitational field is reduced in frequency, or redshifted, when observed in a region of a weaker gravitational field. Freebase (0.00 / 0 votes) Rate this definition:

Gravitational redshift