Everything about Radial Velocity totally explained
Radial velocity is the
velocity of an object in the direction of the line of sight (for example its speed straight towards you, or away from you). The light of an object with a substantial radial velocity will be subject to
Doppler effect, so the frequency of the light decreases for receding objects (
redshift) and increases for approaching objects (
blueshift).
The radial velocity of a
star or other luminous but distant objects can be measured accurately by taking a high-resolution
spectrum and comparing the measured
wavelengths of known
spectral lines to wavelengths from laboratory measurements. By convention, a positive radial velocity indicates the object is receding; if the sign is negative, then the object is approaching.
In many
binary stars, the
orbital motion usually causes radial velocity variations of several kilometers per second. As the spectra of these stars vary due to the Doppler effect, they're called
spectroscopic binaries. Radial velocity studies can be used to estimate the masses of the stars, and some
orbital elements, such as
eccentricity and
semimajor axis. The same method has also been used to detect
planets around stars, in the way that the movement's measurement determines the planet's orbital period, while the resulting size of the displacement allows the calculation of the lower bound on a planet's
mass. Radial velocity methods alone may only reveal a lower bound, since a large planet orbiting at a very high angle to the line of sight will perturb its star radially as much as a much smaller planet with an orbital plane on the line of sight.
Further Information
Get more info on 'Radial Velocity'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://radial_velocity.totallyexplained.com">Radial velocity Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |