This is an example of a graphic of the linear regression.
The light curve analysis consists to found, with observations, a well-defined data ponits obtained through repeated measurements over a certain time range. This graphic is used to compute the distance and with this information the radius can be found and consecuently the mass of the star or the exoplanet.
The linear regresion is used to interpole the data ponits of the exoplanet's radius to found their respective mass, also we can used to found the R (is the number that indicates how close the points are to the generated line), the a (the slope) and the b (the term that passes through the axis of ordinates). And this for numbers are calculed with these formulas:
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This is an example of a graphic of the linear regression. |
Parallax is the displacement or the change in the apparent position of the object when viewed from two different points of view. Astronomers regularly use the parallax method to measure the distances of the closer stars.
Parallax formula is based in the parallax angle in arcseconds. Making this the distance in "Parsecs".
The formula of parallax method |
The Capheid variable stars, such as name suggests, are stars that have a vary on a regular cycle. Tha astronomers use the light curve to fuond the maximum point in the graph, went the star has its greatest brightness, and the minimum is the point where it is faintest. With this information, the astronomers can found the brightness of the star and if it's closer or farther.
In the second graph, we can see a imaginary line with all the stars putted in the graph, and the astronomers concluded that is directly proportional the regular cycle of the star with the brightness of the star.
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Light curve |
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RR Lyrae Stars |
In a binary stars, we can also found datas points to make a graphic of the brightness of each of the stars, and with that graphic we can determine which is in front in the case two in the same in the case four. We can compere the two stars to see which one is more brightness, and with this information we can found the distance or the radius.
Doppler spectroscopy was the first technique used to reveal the existence of extrasolar planetary systems hosted by solar-type stars. The use of powerful spectrographs to detect distant planets.
This is the formula to calculate the exoplanet's brightness or radius. |
Determine the physical parameters of a transiting planet and its host star from photometric and spectroscopic analysis, it is essential to independently measure the stellar mass. This is often achieved by the use of evolutionary tracks and isochrones, but the mass result is only as reliable as the models used.
