Sentences with phrase «velocity variations»
"Velocity variations" refers to changes or fluctuations in speed or pace. It means that the rate at which something or someone moves is not constant and can either speed up or slow down at different points. Full definition
[1] Most of the exoplanets currently known were discovered using indirect techniques — such as radial velocity variations of the host star, or the dip in brightness of the star caused by a transiting exoplanet.
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Due to the close binary orbital interactions of the host star with Alpha Centauri A and Star B's own increased stellar activity during recent years, the astronomers were only able to detect the radial - velocity variations of host star B that were caused by the 3.236 - day orbit of the planet (with a semi-major axis of 0.04 AU) only after more than four and a half years of careful observation.
The detected velocity variations were too small to be cause by a body orbiting star A, which is more massive (see HR 5544 on page 919).
The radial - velocity variations indicate a highly eccentric orbit with a period of 153.9 days.
If you are new to this saga make sure you read Tau II Abstract: The successful detection is reported of radial - velocity variations due to orbital motion of the substellar companion of the star tau Boötis, from data obtained with a small aperture (0.4 - m) telescope and a fibre - fed high resolution spectrograph.
Herman, F., Anderson, B. & Leprince, S. Mountain glacier velocity variation during a retreat / advance cycle quantified using sub-pixel analysis of ASTER images.
However, the high luminosity of the primary star, intense Ca II H and K emission (Smith and Dominy, 1979), and radial velocity variations somewhat larger than can be accounted for by the expected uncertainties suggested that Delta Eridani might be an RS CVn - type binary and therefore a photometric variable like most members of that class.
Analysis of radial velocity variations suggest that this probable red dwarf star has about 15 percent of Sol's mass (Irwin et al, 1992).
Arcturus exhibits both short - and long - period Doppler velocity variations with amplitudes of order 150 meters (492 feet) per second (Hatzes and Cochran, 1994 and 1993).
In 1988, Campbell et al also reported finding small velocity variations that could be the result of a substellar object of one to nine times the mass of Jupiter that may orbit Xi Boötis B.
It is demonstrated that the periodicity of the solid runoff correlates with the 18.6 - year periodicity of the Earth's angular velocity variations caused by the 18.6 - year cyclicity of the variability of lunisolar tides.
According to the Yale Bright Star Catalogue, 1991 5th Revised Edition notes entry for HR 4983, analysis of spectroscopy and velocity variations over at least five years initially suggested that Beta Comae Berenices may have an unseen companion, which was unresolved by speckle interferometry (Hartkopf and McAlister, 1984, page 109).
Within two days, however, the discovery announcement was retracted because the detected radial velocity variations could be attributed to the aging star's pulsations (more).
This so - called radial velocity variation is what astronomers often measure to find exoplanets.
Found via radial velocity variations, the planet's true mass could not be known with knowing whether its orbit around Star B is being viewed edge - on, face - on, or somewhere in between.
The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large transit - timing variations, radial - velocity variations, Warm - Spitzer observations, and statistical analysis of false - positive probabilities.
The primary shows long - period radial velocity variations that indicate the presence of a low mass companion whose projected mass is in the planetary regime (m sin i = 9.33 Mjup).
This result was unexpected because no companion had been reported previously and because the star's previously known characteristics (such as observed radial velocity variations) were incompatible with Arcturus as a binary system (R. F. Griffin, 1998).
Radial velocity variations have been detected (Andrei A. Tokovinin, 1992).
Scientists were also able use the infrared spectroscopy to look at radial velocity variations (an analysis of the light spectrum) to determine that water was present.
In addition, Tau Ceti does not appear to have a close stellar or substellar companion based on astrometric measurements (Lippincott and Worth, 1980), radial velocity variations (Campbell et al, 1988; and near - infrared interferometry (Di Folco et al, 2007).
These signs were either radial velocity variations (1 star), Hα line profile variability (2 stars), double - lined profiles (9 stars) or visual binarity seen in the slit viewer images (4 stars).
The discovery has yet to be confirmed, and some astronomers suspect that the radial velocity variations may actually reflect a long - term oscillation in Star A itself.