Mass-radius relationship

The mass-radius relationship in astronomy states that for a star located on the main sequence of the Hertzsprung-Russell diagram , the following relationship exists between its radius in solar radii and its mass in solar masses : ${\displaystyle R}$ ${\displaystyle R_{\odot }}$ ${\displaystyle M}$ ${\displaystyle M_{\odot }}$

• for stars with less than 1.66 solar masses ( ): ${\displaystyle \mathrm {M<1{,}66\,M_{\odot }} }$

${\displaystyle {\frac {R}{R}}_{\odot }=1{,}06\cdot \left({\frac {M}{M}}_{\odot }\right)^{0{,}945}}$

• for stars with more than 1.66 solar masses ( ): ${\displaystyle \mathrm {M>1{,}66\,M_{\odot }} }$

${\displaystyle {\frac {R}{R}}_{\odot }=1{,}33\cdot \left({\frac {M}{M}}_{\odot }\right)^{0{,}555}}$.

The above formulas show that the average mass densities of the stars are not constant.

literature

• Osman Demircan and Göksel Kahraman: Stellar mass-luminosity and mass-radius relations . In: Astrophysics and Space Science . tape 181 , no. 2 , 1991, p. 313-322 .

See also

• Mass-luminosity relationship
• Luminosity-temperature relationship