Astronomy: The Use Of Wien’s Law

  1. Use Wien’s law to determine the peak wavelength of light generated by 10 million Kelvin gas in an accretion disk around a black hole. What type of photons have this wavelength?

Answer: 0.2898 nm, x-rays


Assuming that λpeak represents the peak wavelength in nanometers, and T represents the object’s temperature in Kelvin, the formula of Wien’s law is the following:


. Temperature is given as 10,000,000 Kelvin, or 107. Therefore, . Considering this value lies within the range from 0.01 nanometers to 10 nanometers, it can be concluded that it corresponds to an emission of X-ray (Columbia University, n.d.). Thus, the wavelength of light generated by 10 million Kelvin gas in an accretion disk around a black hole is 0.2898 nm, having X-ray photons.

2. In your own words, discuss/explain why mass an important factor in the life of a star. Be as detailed as needed and include where you found your information.


Mass is one of the most significant and unusual characteristics of a star. Firstly, it is possible to establish the limits of the age of a star of a given mass, which is in a particular stage of stellar evolution. Generally, stars lose their mass as they age, especially at the ends of their lives (Petersen, 2019). Therefore, scientists can accurately calculate the age of a star and predict its fate by using its mass. Secondly, mass determines the force of gravitational compression of the luminary, which is the primary condition for the core of the start to catch fire in a thermonuclear reaction and start emitting light (Petersen, 2019). In astrophysics, this is called “the mass-luminosity relation.”

Consequently, mass is a passing criterion in the category of stars. It is logical that the greater the mass of the star, the higher its luminosity (Petersen. 2019). For instance, too light objects such as brown dwarfs are not able to shine properly. Indeed, there is more hydrogen fuel for thermonuclear reaction in the massive star, and the gravitational compression which activates this process is stronger. Considering the above, it is evident that mass is an essential factor in the life of a star because it helps astronomers to determine at what stage of life the star currently is.