Question

The wavelength of peak emission from any star is related to the temperature of its photosphere (i.e., the emitting surface) by Wien’s Law, given by λ = 2,900/T, where λ is the wavelength in micrometers (1 µm = 10-6 m), and T is the temperature of the star in Kelvin (see textbook’s figure 3.27 for help). Answer the following questions using the above equation.

2.1. The most massive star ever observed is a Wolf-Rayet type-star, named R136a1. It is so massive that it defies the standard stellar classification system (i.e., OBAFGKM). R136a1 has a mass of ~300 solar masses (M◉), and a luminosity equivalent to ~9 million solar luminosities (L◉). R136a1 has a photospheric temperature of 53,000 K.

(a) What is its wavelength of peak emission in µm? And in nanometers (nm)?

(b) What part of the electromagnetic spectrum is this?

(c) What color would you expect R136a1 to appear to the naked eye?

Answer 1