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Lecture 9: Stellar Spectra
Lecture 9: Stellar Spectra

... Example: the Effects of Dust There is gas and dust in between the stars. Dust particles are very small and scatter blue light more efficiently than red light. Most stars appear to be REDDER than they really are. A star’s color no longer tells you its tempertuare. But the spectrum still does! ...
Practice Exam for 3 rd Astronomy Exam
Practice Exam for 3 rd Astronomy Exam

... OB Association In the Milky Way Galaxy there are very many Giant Molecular Clouds (GMC). A typical GMC contains most hydrogen and helium gas and microscopic solid particles of ice and rocky material known collectively as “dust”. The typical GMC may be 300 ly in diameter and encompass 300,000 solar m ...
Astronomy Worksheet
Astronomy Worksheet

... *In the cool G and K stars lines from ionized metals are less abundant and lines from neutral metals are more common. *In the very cool M stars, their atmospheres are cool enough to have molecules that produce wide absorption “bands”, which are much wider than the atomic spectral lines. These absorp ...
Deducing Temperatures and Luminosities of Stars
Deducing Temperatures and Luminosities of Stars

mass_spetral
mass_spetral

Three types of binary stars.
Three types of binary stars.

CASPEC Observations of the Most Metal-Deficient Main
CASPEC Observations of the Most Metal-Deficient Main

... give a list of 12 Galactic stars of this type with known distances. If we place these stars in the SMC, their V magnitudes will range from 17 to 22. The brightest one, HD 200775, assumed to lie at 440 pc from the Sun (Whitcomb et al., 1981), may be fainter than 17 if its distance is overestimated. T ...
Spectra of Star Clusters
Spectra of Star Clusters

Stellar Evolution of a Star like the Sun
Stellar Evolution of a Star like the Sun

... Massive stars have more gravitational Energy that can be used to heat the central core. The central temperature need to be hotter and hotter each time a new nuclear fuel is used. Burning H to He requires tens of millions of degrees Kelvin. Burning Helium requires a higher temperature because the rep ...
Distance, Size, and Temperature of a Star
Distance, Size, and Temperature of a Star

Document
Document

... distance of one of the objects from the other cubed. This is a simple problem that only works if you do the following: P must be in earth years, and amust be in au. An au is the distance from the earth to the Sun (93 million miles). Mars is 1.5 au , and Jupiter is 5 au. So lets use the formula on th ...
Thermal Equilibrium
Thermal Equilibrium

... Kelvin are never obtained. This is because lower mass stars do not have enough gravitational energy for the central temperatures to rise this high. Thus low star masses finish their nuclear reactions after having produced Carbon and a little Oxygen. Higher mass stars can burn Carbon, then burn Oxyge ...
SNC 1D - othsmath
SNC 1D - othsmath

... the next layers outward. Stars rotate. They rotate faster in the middle than they do at the poles A vast cloud of gas and thought to be the birthplace of stars and planets. The hot, condensed object at the centre of a nebula; very young star. The process of energy production in which hydrogen nuclei ...
star - TeacherWeb
star - TeacherWeb

... of the H-R diagram. • Band extends from cool, dim, red stars at the lower right to hot, bright, blue stars at the upper left  known as Main Sequence. • Stars within this band are called main sequence stars. ie. Sun ...
lecture_5_mbu
lecture_5_mbu

... Occurs in Sun but minor compared to PPI More important fusion process for stellar masses >1.1M sun Since requires a C nucleus, only occurs in Pop I stars Second and fifth steps occur because 13N and 15O are unstable isotopes with half lives of only a few minutes Dr Matt Burleigh ...
Star Of Wonder
Star Of Wonder

... bomb) to release much heat and light. The object recorded in 5 BC by the Chinese could have been a nova rather than a comet, and this could in fact have been the Star of Bethlehem. Because it's so stupendous, my favorite hypothesis has always been a supernova, the dramatic brightening of a star cau ...
Luminosity
Luminosity

... •  Mv is absolute visual magnitude and MB is blue etc •  Luminosity is the total amount of energy = bolometric •  Need to make a correction Mv+BolCorrect=Mbol ...
Consider Average Stars
Consider Average Stars

... quickly by holding down the arrow key on your keyboard. This makes the sun set rapidly – and you can watch the stars come out! ...
Astronomy Unit Notes
Astronomy Unit Notes

... Example: a 40 watt light bulb 10 feet away appears brighter than a 40 watt bulb 100 feet away. ...
Scientists Observe Star Triplets Being Born : Space
Scientists Observe Star Triplets Being Born : Space

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Document

...  Stars with small masses (less than a solar mass) are much more common than massive stars (stars more than about 15 to 20 solar masses).  The highest mass stars are very hot and luminous, and can alter the cloud environment. ...
Chapter 10 powerpoint presentation
Chapter 10 powerpoint presentation

... Although the temperatures in the Sun’s core are high, they are not high enough to overcome the coulomb repulsion force resulting from two positively charged nuclei colliding under the laws of classical physics. The solution to this problem is quantum mechanical tunneling. ...
Low mass star formation
Low mass star formation

Figures I through VII in Section 1 on the following sheet
Figures I through VII in Section 1 on the following sheet

... List them in order of decreasing temperature (_1_). List them in order of decreasing strength of their Hydrogen lines (_2_). Which spectrum would most likely have been produced by star B from figure X (_3_)? Of stars C and E in figure X, which is more likely to have produced the spectrum in figure I ...
Star - Uplift Education
Star - Uplift Education

... Suppose I observe with my telescope two red stars A and B that are part of a binary star system. Star A is 9 times brighter than star B. What can we say about their relative sizes and temperatures? Since both are red (the same color), the spectra peak at the same wavelength. ...
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Stellar evolution



Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.
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