The diameter of Rigel Kentaurus, also known as Alpha Centauri, is estimated to be about 1.2 million kilometers. It is a binary star system composed of two stars, Alpha Centauri A and Alpha Centauri B, with Alpha Centauri A being slightly larger and more massive than our Sun.
Rigel or Beta Orionis is a blue/white supergiant star of spectral type B8lab.
The parallax angle of Sirius is approximately 0.38 arcseconds. This value indicates the shift in position of the star as seen from Earth due to its motion around the Sun. The parallax angle is used to calculate the distance to nearby stars.
The parallax shift decreases as distance increases. Objects that are closer to an observer will have a larger apparent shift in position when the observer changes their viewing angle, while objects that are farther away will have a smaller apparent shift in position. This difference in the amount of shift is what allows astronomers to use parallax to calculate the distances to nearby stars.
The distance to the star can be calculated using the parallax angle (in arcseconds) and the formula: distance (in parsecs) = 1 / parallax angle (in arcseconds). Given a parallax of 0.75 arcseconds, the star is approximately 1.33 parsecs away. Converting parsecs to light years (1 parsec β 3.26 light years), the star is about 4.34 light years away.
.2 arc sec
The diameter of Rigel Kentaurus, also known as Alpha Centauri, is estimated to be about 1.2 million kilometers. It is a binary star system composed of two stars, Alpha Centauri A and Alpha Centauri B, with Alpha Centauri A being slightly larger and more massive than our Sun.
Rigel or Beta Orionis is a blue/white supergiant star of spectral type B8lab.
The parallax angle of such distant objects is way too small to be measured. In general, the farther away an object, the smaller is its parallax angle.
Parallax would be easier to measure if the Earth were farther from the sun. This way, there will be a wider angle to the stars using the parallax method.
Sirius will have a greater angle, because it is closer to us.
The parallax angle of Sirius is approximately 0.38 arcseconds. This value indicates the shift in position of the star as seen from Earth due to its motion around the Sun. The parallax angle is used to calculate the distance to nearby stars.
You can conclude that it is farther than a certain distance. How much this distance is depends, of course, on how accurately the parallax angle can be measured.
On the contrary, if the parallax angle is too small, it can't be measured accurately.
Parallax
The parallax shift decreases as distance increases. Objects that are closer to an observer will have a larger apparent shift in position when the observer changes their viewing angle, while objects that are farther away will have a smaller apparent shift in position. This difference in the amount of shift is what allows astronomers to use parallax to calculate the distances to nearby stars.
The distance to the star can be calculated using the parallax angle (in arcseconds) and the formula: distance (in parsecs) = 1 / parallax angle (in arcseconds). Given a parallax of 0.75 arcseconds, the star is approximately 1.33 parsecs away. Converting parsecs to light years (1 parsec β 3.26 light years), the star is about 4.34 light years away.