The Physics Factbook
Edited by Glenn Elert -- Written by his students
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|"Star Formation." World Book Encyclopedia. So-Sz Volume18. Chicago: World Book1989: 849.||"The kind of star that takes shape depends on the mass of the contracting cloud. A cloud with mass about 1/20 that of the sun becomes a red,low-luminosity main sequence star."||0.05 solar mass|
|Cohen, Martin. In Darkness born - The Story of a Star Formation.Cambridge University Press, 1988: 37.||"Both theory and observations concur in defining a minimum protostellar mass for the ignition of the hydrogen fusion to be around 0.08 solar mass. (Jupiter and Saturn for comparison with this limit, are only 0.001 and 0.0003 solar masses)."||0.08 solar mass|
|Wagner/Goldsmith. Cosmic Horizons - Understanding the Universe.The Portable Stanford, 1982: 82.||"Why do all stars have masses not greatly different from that of the sun? Calculations show that balls of gases with less than about 1/10 of the sun's mass cannot produce (through self gravitation) a central temperature hot enough to ignite nuclear reactions."||0.10 solar mass|
|Ronin, A. Colin. The Universe Explained. Holt,1994: 77.||"Since the critical mass needed to set off the nuclear reaction that powers stars is 0.06 times that of the sun, Jupiter would have to be 60 times bigger to become a star."||0.06 solar mass|
Twinkle, twinkle little star how I wonder what you are. Up above the world so high, like a diamond in the sky. Twinkle, twinkle little star how I wonder what you are. If you know this song then you possibly know what a star is. That's right, if you guessed a huge ball of glowing gas in the sky then you are a winner. Tell them what they have won; (In high pitched beautiful blonde showroom voice) well you have won a 200 word description of the mass needed to create a star. [Applause.]
In spite of their appearance stars are enormous objects - ranging from 10 to 100 times the size of the sun. Main sequence stars are ordinary stars like the sun in our own solar system. However, There is a minimal amount of material of matter that is needed in order to produce such a star. life begins in that a cloud of interstellar gas and dust are concentrated in a certain amount of space. The cloud may include the remains of a star that had exploded or it may just be a collection of gases from the surface of the giant-sized stars. The first step is the concentration of the cloud to form a ball - this occurs through millions of years where gravity pulls it together. Due to this the pressure of the gas increases which causes temperature to also increase in a direct manner. When the temperature reaches a certain point (1,100,000 °C) a nuclear fusion reaction occurs. Hydrogen changes into helium to produce a great magnitude of energy. This heats the gas, causing it to shine and creating a star. the kind of star that takes shape depends on the mass of the interstellar cloud. A massive cloud would create a blue, high-luminosity main sequence star. A cloud with less mass would create a red, low luminosity main sequence star (ignoring white dwarfs and variable stars).
The units stated above reflect the absolute minimum amount of interstellar mass needed to form a star. In comparison Jupiter and Saturn lack enough mass needed to form a star (0.001 and 0.0003 solar masses respectively). Such objects must resemble enormous Jupiter-like planets.Jupiter would have to be approximately sixty times bigger to become a star.They should be characterized as dwarf stars since they haven't and will never achieve hydrogen burning.
Kelly Maurelus -- 2001
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