Search results
Results from the WOW.Com Content Network
Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. As of November 2022, about 19.5% of known extrasolar planets ...
Doppler imaging was first used to map chemical peculiarities on the surface of Ap stars.For mapping starspots it was first used by Steven Vogt and Donald Penrod in 1983, when they demonstrated that signatures of starspots were observable in the line profiles of the active binary star HR 1099 (V711 Tau); from this they could derive an image of the stellar surface.
The Doppler temperature is the minimum temperature achievable with Doppler cooling. When a photon is absorbed by an atom counter-propagating to the light source, its velocity is decreased by momentum conservation. When the absorbed photon is spontaneously emitted by the excited atom, the atom receives a momentum kick in a random direction.
While the radial velocity method provides information about a planet's mass, the photometric method can determine the planet's radius. If a planet crosses in front of its parent star's disk, then the observed visual brightness of the star drops by a small amount, depending on the relative sizes of the star and the planet. [6]
The method was first described by Philip Njemanze in 2007, and was referred to as functional transcranial Doppler spectroscopy (fTCDS). [ 25 ] fTCDS examines spectral density estimates of periodic processes induced during mental tasks, and hence offers a much more comprehensive picture of changes related to effects of a given mental stimulus.
The Baade-Wesselink method is a method for determining the distance of a Cepheid variable star suggested by Walter Baade in 1926 and further developed by Adriaan Wesselink in 1946. [1] In the original method the color of the star at various points during its period of variation is used to determine its surface brightness .
The coworker of a newly married woman says she used their recent company holiday party to swindle wedding gifts. After sharing a "sob story" about how she wasn't given enough money from her guests ...
The Doppler parameter, or Doppler broadening parameter, usually denoted as , is a parameter commonly used in astrophysics to characterize the width of observed spectral lines of astronomical objects. It is defined as