In early optical images, quasars looked like single points of light (i.e. point sources), indistinguishable from stars, except for their peculiar spectra.

The fainter member of the pair has a peculiar spectrum that shows a deficiency in metals, which, for astronomical purposes, are the elements heavier than Helium.

"A study of the peculiar spectrum of the star Eta Centauri" (Master's thesis, 1912) is held in the Wellesley College Archives.

This is an Ap star; meaning it has a peculiar spectrum that shows an overabundance of certain elements.

This is classified as an Ap/Bp star, with a peculiar spectrum showing lines of chromium and europium that change in intensity over a period matching the variability cycle, although opposite in phase.

Every shade of their peculiar spectrum was there, in solid, liquid, and gas.

The 29th star on their list, HZ 29, was found to have the most peculiar spectrum out of the set.

It may also be a mildly Am star, which is a class of stars that show a peculiar spectrum with strong absorption lines from various elements and deficiencies in others.

According Cushing et al. 2010, its peculiar spectrum is primarily a result of thin condensate clouds, and also vertical mixing occurs in its atmosphere.

The evidence of the mass of the body was a more serious consideration than its peculiar spectrum.