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K-type main-sequence stars are about three to four times as abundant as G-type main-sequence stars, making planet searches easier. [17] K-type stars emit less total ultraviolet and other ionizing radiation than G-type stars like the Sun (which can damage DNA and thus hamper the emergence of nucleic acid based life). In fact, many peak in the red.
[c] [11] Some of the most massive stars lie within this spectral class. O-type stars frequently have complicated surroundings that make measurement of their spectra difficult. O-type spectra formerly were defined by the ratio of the strength of the He II λ4541 relative to that of He I λ4471, where λ is the radiation wavelength. Spectral type ...
Below there are lists the nearest stars separated by spectral type. The scope of the list is still restricted to the main sequence spectral types: M , K , F , G , A , B and O . It may be later expanded to other types, such as S , D or C .
Additionally, astronomers have found 6 white dwarfs (stars that have exhausted all fusible hydrogen), 21 brown dwarfs, as well as 1 sub-brown dwarf, WISE 0855−0714 (possibly a rogue planet). The closest system is Alpha Centauri , with Proxima Centauri as the closest star in that system, at 4.2465 light-years from Earth.
Beta Cassiopeiae (β Cassiopeiae, abbreviated Beta Cas or β Cas), officially named Caph / ˈ k æ f /, [12] [13] is a Delta Scuti variable star in the constellation of Cassiopeia. It is a giant star belonging to the spectral class F2. The white star of second magnitude (+2.28 mag, variable) has an absolute magnitude of +1.3 mag.
These alignments have different names depending on the number of stars visible. Three planets constitutes a mini alignment. Four planets are a small alignment, which we saw during April 8’s eclipse.
The planets will stretch from the horizon line to around halfway up the night sky. But don't be late: Mercury and Jupiter will quickly dip below the horizon around half an hour after sunset.
MS stars, intermediate with normal class M stars, have barely detectable ZrO but otherwise normal class M spectra. SC stars, intermediate with carbon stars, have weak or undetectable ZrO, but strong sodium D lines and detectable but weak C 2 bands. [3] S star spectra also show other differences to those of normal M class giants.