In what sense are the quasars "quasi-stellar"?
A) Their energy production is hydrogen-helium fusion, like main sequence stars.
B) They are upscale versions of O stars, yet hundreds of times more massive.
C) Their luminosity comes from the millions of supergiants that compose them.
D) Their spectra is like that of ordinary stars.
E) In short time exposures, their images looked stellar.

Question

Quizplus · Accepted Answer

The term "quasi-stellar" was originally used for quasars because in early telescopic observations, they appeared as point-like sources similar to stars. However, as observations improved, their extreme luminosity and unusual spectral features revealed that they are actually supermassive black holes at the centers of galaxies, actively accreting matter and emitting massive amounts of energy.

In What Sense Are the Quasars "Quasi-Stellar