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Of the main-sequence star types, stars more massive than 1.5 times that of the Sun (spectral types O, B, and A) age too quickly for advanced life to develop (using Earth as a guideline). On the other extreme, dwarfs of less than half the mass of the Sun (spectral type M) are likely to tidally lock planets within their habitable zone, along with ...
Formally, the wavelength version of Wien's displacement law states that the spectral radiance of black-body radiation per unit wavelength, peaks at the wavelength given by: = where T is the absolute temperature and b is a constant of proportionality called Wien's displacement constant, equal to 2.897 771 955... × 10 −3 m⋅K, [1] [2] or b ...
Spectrochemistry is the application of spectroscopy in several fields of chemistry. It includes analysis of spectra in chemical terms, and use of spectra to derive the structure of chemical compounds, and also to qualitatively and quantitively analyze their presence in the sample.
A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. [1] B-type stars are extremely luminous and blue.
Others include CN, CH, MgF, NH, C 2, SrF, ZrO, YO, ScO, and BH. [5] Stars of most types can contain molecules, even the Ap category of A-type stars. Only the hottest O-, B-, and A-type stars have no detectable molecules. Carbon-rich white dwarfs, even though very hot, have spectral lines of C 2 and CH. [6]
Spectroscopy is a branch of science concerned with the spectra of electromagnetic radiation as a function of its wavelength or frequency measured by spectrographic equipment, and other techniques, in order to obtain information concerning the structure and properties of matter. [4]
The term subgiant was first used in 1930 for class G and early K stars with absolute magnitudes between +2.5 and +4. These were noted as being part of a continuum of stars between obvious main-sequence stars such as the Sun and obvious giant stars such as Aldebaran, although less numerous than either the main sequence or the giant stars.
Class II objects have circumstellar disks and correspond roughly to classical T Tauri stars, while Class III stars have lost their disks and correspond approximately to weak-line T Tauri stars. An intermediate stage where disks can only be detected at longer wavelengths (e.g., at 24 μ m {\displaystyle 24{\mu }m} ) are known as transition-disk ...