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Stellar evolution is the process by which a star changes over the course of its lifetime and how it can lead to the creation of a new star. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the current age of the ...
The Yerkes spectral classification, also called the MK, or Morgan-Keenan (alternatively referred to as the MKK, or Morgan-Keenan-Kellman) [18] [19] system from the authors' initials, is a system of stellar spectral classification introduced in 1943 by William Wilson Morgan, Philip C. Keenan, and Edith Kellman from Yerkes Observatory. [20]
1718 — Edmund Halley discovers stellar proper motions by comparing his astrometric measurements with those of the Greeks; 1782 — John Goodricke notices that the brightness variations of Algol are periodic and proposes that it is partially eclipsed by a body moving around it; 1784 — Edward Pigott discovers the first Cepheid variable star
The "anchor points" of the MK classification system among the K-type main-sequence dwarf stars, i.e. those standard stars that have remain unchanged over the years, are: [12] Sigma Draconis (K0 V) Epsilon Eridani (K2 V) 61 Cygni A (K5 V) Other primary MK standard stars include: [13] 70 Ophiuchi A (K0 V), 107 Piscium (K1 V) HD 219134 (K3 V) TW ...
The current stellar classification system originated in the early 20th century, when stars were classified from A to Q based on the strength of the hydrogen line. [191] It was thought that the hydrogen line strength was a simple linear function of temperature.
It is the earliest phase in the process of stellar evolution. [1] For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. [2] The phase begins when a molecular cloud fragment first collapses under the force of self-gravity and an opaque, pressure-supported core forms inside the collapsing fragment.
The most powerful telescope to be launched into space has made history by detecting a record number of new stars in a distant galaxy. NASA's James Webb Space Telescope, history's largest and most ...
The Yellow CESAM code, stellar evolution and structure Fortran source code; EZ to Evolve ZAMS Stars a FORTRAN 90 software derived from Eggleton's Stellar Evolution Code, a web-based interface can be found here . Geneva Grids of Stellar Evolution Models (some of them including rotational induced mixing) The BaSTI database of stellar evolution tracks