In the formula used to calculate ellipticity ($10 imes (1 - b/a)$), what do the variables $a$ and $b$ represent?
Answer
$a$ is the semi-major axis and $b$ is the semi-minor axis.
The ellipticity calculation is based on the apparent major semi-axis ($a$) and the apparent minor semi-axis ($b$) of the galaxy's image projected onto the sky.
Related Questions
What visual feature distinguishes spiral galaxies from elliptical galaxies?According to Gérard de Vaucouleurs' classification scheme, what do the E0 and E7 designations represent?In the formula used to calculate ellipticity ($10 imes (1 - b/a)$), what do the variables $a$ and $b$ represent?What is a crucial limitation regarding the E classification system for elliptical galaxies?What characteristic color do elliptical galaxies typically exhibit when viewed through optical telescopes?Why is ongoing star formation typically negligible in elliptical galaxies compared to spiral galaxies?How are the stellar motions primarily supported within a typical elliptical galaxy?How do the stellar motions in flatter elliptical galaxies ($ ext{E}4$ to $ ext{E}7$) sometimes differ from the most spherical $ ext{E}0$ galaxies?What major violent event is primarily thought to be responsible for forming massive elliptical galaxies?In which type of environment are elliptical galaxies found to be significantly more common?