Polaris is listed as F7 in the Sky Catalogue 2000.0.
The spectral class is A0Va.
No. Polaris is a multiple star system. In the late 18th century it was resolved into two components, Polaris A and Polaris B. Later, Polaris A was resolved further into Polaris Aa and Polaris Ab. Neither Polaris Aa nor Polaris Ab are red giants. Aa is a supergiant and Ab is a dwarf; both of them are spectral class F ("yellow-white").
No. Polaris is a multiple star system. In the late 18th century it was resolved into two components, Polaris A and Polaris B. Later, Polaris A was resolved further into Polaris Aa and Polaris Ab. Neither Polaris Aa nor Polaris Ab are red giants. Aa is a supergiant and Ab is a dwarf; both of them are spectral class F ("yellow-white").
Antares has a spectral class of M1LB.
Spectral class Y, which is typical of "brown dwarf" stars.
Sirius is a double star. The brighter component ... the one you actually notice in the night sky ... is spectral class A1V. The faint 'secondary' component is spectral class DA2.
Spectral class is a classification system for stars based on their temperature and spectral characteristics. It categorizes stars into different groups, such as O, B, A, F, G, K, and M, with O being the hottest and M being the coolest. Spectral class is indicated by a letter, with additional subtype information denoted by a number.
The O spectral class is the highest temperature class. Stars in this class are extremely hot and blue in color, with surface temperatures exceeding 30,000 K.
Two stars of the same spectral class must have the same temperature and color. This classification system groups stars based on their temperature, with each spectral class representing a specific range of temperatures.
Polaris is the brightest star in the constellation Ursa Minor.
A star with a spectral class of O is classified as a Blue Star. A red star will have a spectral class of M See related question
The spectral class letters in astronomy represent the temperature and color of stars. The sequence starts with O (hottest and bluest stars) and ends with M (coolest and reddest stars). The spectral class letters are O, B, A, F, G, K, and M.