A powerful telescope can observe an object down to about the 30th magnitude in the B-band. To what distance can this kind of telescope observe a star such as the Sun? What kind of energy flux is observed at this telescope in terms of the solar constant? (Show your work for all calculations)
Stellar evolution
We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.
Red Shift
It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.
A powerful telescope can observe an object down to about the 30th magnitude in the B-band. To what distance can this kind of telescope observe a star such as the Sun? What kind of energy flux is observed at this telescope in terms of the solar constant? (Show your work for all calculations)
To determine the distance at which a telescope can observe a star such as the Sun, we can use the following formula:
m - M = 5 log(d) - 5
where: m = the apparent magnitude of the star M = the absolute magnitude of the star d = the distance to the star in parsecs
We can assume that the Sun has an absolute magnitude of 4.83 and an apparent magnitude of -26.74 in the B-band. Substituting these values into the formula, we get:
-26.74 - 4.83 = 5 log(d) - 5 -31.57 = 5 log(d) - 5 -26.57 = 5 log(d) log(d) = -5.314 d = 10^(-5.314) parsecs
Converting parsecs to meters, we get:
d = (3.086 × 10^16 meters/parsec) x 10^(-5.314) parsecs d = 1.18 x 10^12 meters
So the telescope can observe the Sun at a distance of approximately 1.18 x 10^12 meters.
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