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Topic: Main-sequence

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GAT: main sequence - Wikibooks, collection of open-content textbooks Main sequence is a term that describes those stars that are classified to reside on the predominate, slightly curved, diagonal line running from the upper left corner to the lower right corner of the Hertzsprung-Russell diagram. Stars that have yet to settle down as a main sequence star are still in their formation stages and are known as protostars such as T-Tauri stars. Stars that have moved away (or have "turned off") from the main sequence line are in the process of converting their helium into higher elements and in the late stages of their lives. en.wikibooks.org /wiki/GAT:_main_sequence   (300 words)

Main sequence - Wikipedia, the free encyclopedia Main sequence is also the name of a composition of music by composer Vangelis on his 1976 album, Albedo 0.39 and is in reference to the astronomical term. The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. But even perfect observations would lead to a fuzzy main sequence, because mass, after all, is not the only parameter a star has. en.wikipedia.org /wiki/Dwarf_star   (442 words)

Main Sequence Turn-off Ages The use of the luminosity of the main sequence turn-off as an age indicator requires that the distance to the globular cluster be known. The Sun is a typical main sequence star, whose structure (convective envelope, radiative interior) is quite similar to main sequence globular cluster stars. Main sequence, and red giant branch globular cluster stars have surface convection zones. astron.berkeley.edu /~jleaman/classes/cosmology_with_CP/project/Main_Sequence_Turn-off_ages.htm   (944 words)

Stars Main sequence stars have zones (in radius) which are convective, and zones which are radiative, and the location of these zones depends on the behavior of the opacity, in addition to the other properties of the star. Before and after the main sequence, the heat sources differ slightly: before the main sequence the star is contracting, and is not yet hot nor dense enough in the interior for the nuclear reactions to begin. They finish their main sequence lifetime in a way similar to the lower mass stars, but become brighter and cooler on the outside and are called red supergiants. imagine.gsfc.nasa.gov /docs/science/know_l2/stars.html   (2265 words)

Main Sequence Stars Main sequence stars essentially have a fixed size that is a function of their mass. Main sequence stars are characterised by the source of their energy. Mass is the key factor in determining the lifespan of a main sequence star, its size and its luminosity. outreach.atnf.csiro.au /education/senior/astrophysics/stellarevolution_mainsequence.html   (3203 words)

main sequence A star on the main sequence is one that is generating light and heat by the conversion of hydrogen to helium by nuclear fusion in its core. The least massive, hydrogen-burning stars, the red dwarfs, sit to the lower right and may remain on the main sequence for hundreds of billions of years. A star arrives on the main sequence after it starts hydrogen burning in its core and remains there throughout its core-hydrogen-fusion phase. www.daviddarling.info /encyclopedia/M/mainseq.html   (250 words)

Main Sequence Stars Stars along the main sequence (MS) all have one thing in common: they are all burning hydrogen into helium in their cores. In the Main Sequence Phase of a star's evolution, radiation pressure pushing outward exactly balances the gravitational pressure pulling inward (this balance is called Hydrostatic Equilibrium). These stars contract slowly and never become Main Sequence stars. www.astro.umd.edu /education/astro/stev/main_seq.html   (525 words)

MAIN SEQUENCE STARS It is thought that the main sequence stage is the longest stage in a star’s fusion-dominated life. Our Sun is thought to have a main sequence life span of approximately 10 billion years.     The amount of time that a star remains in the main sequence is a function of its mass. cse.cosm.sc.edu /hses/StarEvol/pages/main.htm   (533 words)

class9.txt A star during this phase is called a sub-giant, because its radius is expanding as it leaves the main sequence. Leaving the Main Sequence We've now talked about stars during the main part of their lifetimes and stars during their birth. Main Sequence Lifetimes Let's start by reviewing what we know about the lifetimes of stars on the main sequence. astron.berkeley.edu /~krumholz/sq/astro/class9.txt   (2313 words)

ASTR 103: Stellar - Pre-Main-Sequence Evolution It is usual among astronomers to date a star's age from the zero-age main sequence onward, since the time it has spent contracting out of the interstellar medium to the main sequence is only a small fraction of its life span, typically a few tenths of a percent. Astronomers define the zero-age main sequence (Figure 17.11) as the line along which protostars of different masses cease to contract (and thus are stable configurations) and derive all their luminosity by burning hydrogen. By the time several O stars arrive on the zero-age main sequence from the collapse of a giant molecular cloud, they will produce enough ultraviolet radiation to evaporate dust grains and ionize gas in their vicinity; this process forms an H II region. www.physics.gmu.edu /~jevans/astr103/CourseNotes/Text/Lec05/Lec05_pt2_txt_stellarPreMSEvol.htm   (2175 words)

StarsIntro If the white dwarf and main sequence remnant of a close double are close enough, the white dwarf can raise tides in the main sequence star, and mass will flow the other way, from the main sequence star to the white dwarf. The higher the mass of the main sequence star, the greater its diameter and the higher its surface temperature. When the giant becomes a white dwarf we are left with a seemingly single star (main sequence or evolved giant) with an odd chemical composition. www.astro.uiuc.edu /~kaler/sow/star_intro.html   (5419 words)

Promela Reference -- unless(3) The executability of all basic statements in the main sequence is constrained to the non-executability of all guard statements of the escape sequence. If all guards of the escape sequence remain unexecutable throughout the execution of the main sequence, the escape sequence as a whole is skipped. Following the semantics model, the guard statements of an escape sequence are assigned a higher priority than the basic statements from the main sequence. spinroot.com /spin/Man/unless.html   (588 words)

Zoom Astronomy Glossary: M The main sequence turnoff is the place on the Hertzsprung-Russell Diagram where an aging (evolving) star begins to run out of hydrogen in the core and expand, thus moving off the main sequence. Main sequence stars are the central band of stars on the Hertzsprung-Russell Diagram. The sun is a typical Main Sequence star. www.enchantedlearning.com /subjects/astronomy/glossary/indexm.shtml   (4064 words)

Stellar Evolution I Because the transmutation of Hydrogen into Helium is the most efficient of the nuclear burning stages, the main sequence phase is the longest phase of a star's life, about 10 billion yrs for a star with 1 solar mass. During the main sequence phase there is a "feedback" process that regulates the energy production in the core and maintains the star's stability. During this phase the star lies above the main sequence; such pre-main sequence stars are observed as T-Tauri Stars, which are going through a phase of high activity. cassfos02.ucsd.edu /public/tutorial/StevI.html   (1515 words)

G. C. Sloan: Main Sequence Stars, Giants, and Supergiants Main sequence stars provide their energy by fusing hydrogen atoms together to produce helium. In this bizarre geometry, even though the interior temperature is far hotter than n the main sequence, the outer layers expand and cool, producing a red giant. Temperature translates to color, and this relationship between color and brightness (luminosity) for hydrogen-burning stars is called the main sequence. isc.astro.cornell.edu /~sloan/fun/star.html   (839 words)

Lives and Deaths of Stars The most accurate age for a cluster is found from fitting the entire cluster HR diagram (main sequence, sub-giant, red giant, and horizontal branch) to a stellar evolution model of a specific age and chemical composition. This means that an old cluster will have only the low-mass stars still on the main sequence, but a young cluster will have both high and low-mass stars on the main sequence. That point on the main sequence is called the main sequence turnoff. www.astronomynotes.com /evolutn/s9.htm   (602 words)

Properties of Stars Notice the trends in the table: as the temperature of the main sequence star increases, the mass and size increase. Also, because of the relation between luminosity and the size and temperature of a star, hotter main sequence stars are more luminous than cooler main sequence stars. Red giants, supergiants, white dwarfs are not main sequence stars. www.astronomynotes.com /starprop/s12.htm   (1409 words)

Stellar Evolution: Main Sequence Once the last of the hydrogen is used up in the core of an aging main sequence star, fusion stops in the core and the temperature drops and the core collapses. The proton-proton chain is the main source of energy for main sequence stars. This whole process takes several million years but, in the end, the main sequence star becomes either a red supergiant or a red giant, depending on its initial mass. zebu.uoregon.edu /~js/ast122/lectures/lec14.html   (1312 words)

The Main Sequence The main sequence lifetime of an M star is comfortably longer than the age of the universe (about 15 billion years). Thus, every M-type main sequence star that has ever been created is still chugging away, converting hydrogen into helium in its core. On the other hand, every O-type main sequence star in existence must be very young (under a million years old). www.stormpages.com /swadhwa/stellarevolution/lecture14.htm   (1102 words)

DSA Techniques for Fast and Robust Acquisition of DS/CDMA Scrambling Codes Once the igniter sequence is identified, the MS differentially detects the state symbol, demaps it to a pair of state samples, and acquires the primary scrambling code through the comparison-correction-based main SRG synchronization process. The state samples are scrambled by the igniter sequence and conveyed over the pilot channel, while the user data is scrambled by the main sequence and transmitted over the user channel. The four element sequences and their shifted versions, shifted by 64, 128, and 192 chips, constitute a set of 16 different igniter sequences which are also time-aligned to GPS timing. www.comsoc.org /ci/private/2000/nov/lee.html   (3930 words)

Hertzsprung-Russell Diagram About 90% of the known stars lie on the Main Sequence and have luminosities which approximately follow the mass-luminosity relationship. For main sequence stars, the luminosity increases with the mass with the approximate power law: Evolution of the Sun to the Main Sequence hyperphysics.phy-astr.gsu.edu /hbase/astro/herrus.html   (95 words)

Exercise 1.3: Distance to the Open Clusters The nearest star cluster with a well populated main sequence, the Hyades Cluster in the constellation Taurus, is crucial to this technique. If we assume that the main sequence stars in the other clusters have the same true luminosities as their counterparts in the nearby cluster, we can calculate their distances with the luminosity-distance formula. The method of obtaining the cluster distance is called main sequence fitting because it relies on "fitting" the main sequence on the cluster diagram to the standard main sequence. www.astro.lsa.umich.edu /Course/MMSS/Interactive/Ex1.3   (1235 words)

Star Clusters Understanding the changes in the lifetime of a main sequence star is a simple matter of nuclear physics, where we can calibrate the turn-off points for various clusters to give their ages. Therefore, the older the cluster, the fewer stars to be found at the top of the the main sequence, and an obvious grouping of red giants will be seen at the top right of the HR diagram. The main sequence is the line through the middle of the figure. zebu.uoregon.edu /~js/ast122/lectures/lec15.html   (1046 words)

Subsequent development on the main sequence (from star) --  Britannica Student Encyclopedia More results on "Subsequent development on the main sequence (from star)" when you join. The star then reaches the main sequence where it remains for most of its active life. Birth of stars and evolution to the main sequence www.britannica.com /ebi/article-52850   (921 words)

Life on the Main Sequence Lifetimes, luminosities, and surface temperatures on the main sequence. Convection and radiative energy transport in main sequence stars. The star lies on the edge of a thick molecular cloud and the nebula contains shocks associated with the interaction of the wind with the interstellar medium, and also excitation of previously expelled material. csep10.phys.utk.edu /astr162/lect/mainseq/mainseq.html   (154 words)

Main sequence - Wikipedia, the free encyclopedia Stars usually enter and leave the main sequence from above when they are born or they are starting to die, respectively. The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. Actually, there are very metal-poor stars ( subdwarfs) that lie just below the main sequence although they are fusing hydrogen, thus marking the lower edge of the main sequence's fuzziness due to chemical composition. en.wikipedia.org /wiki/Main_sequence   (154 words)

Star Data Table For example, let's assume that a science fiction writer desires to set a story around the star gamma Virginis, which he or she finds is an F0 main sequence star. The following table contains data on the "life zones" of main sequence stars. Reading across the table in the F0 row he or she finds (to the left) that the star has a bolometric magnitude of 2.75. www.io.com /~iareth/mainsequence.html   (700 words)

itymbi ...: SEQUENCE Archives One use of that would be to make the sequence diagrams part of the JavaDoc documentation; the.png files would be automatically generated from the diagram "script" (any idea for a standard extension?) and the script would be kept under source control with the rest of the code. It produces sequence diagrams from executing code and is the sort of thing the inspires, and embarrasses, me into picking up SEQUENCE again and making some improvements. I'm using sequence v7, and I'm having a nasty bug that I can't seem to resolve. www.zanthan.com /itymbi/archives/cat_sequence.html   (6575 words)

Stellar Evolution and Death -- The Main Sequence Due to its prominence, this band is called the "main sequence." Most stars are main sequence stars. The diagram shows the main sequence, red giants, supergiants, and white dwarfs. Stellar Evolution and Death -- The Main Sequence observe.arc.nasa.gov /nasa/space/stellardeath/stellardeath_1ai.html   (239 words)

MTV.com - Movies - News - Rewind: The Dying Art Of The Main Title Sequence The main title sequence, that happy marriage of words, music and image, is becoming a thing of the past, and, without being overly dramatic, it's going to forever change the moviegoing experience... Sadly, the future of the main title sequence seems to be as bleak as that of 2D feature animation, the indie record store or Verne Troyer's dignity. A really good main title sequence is like a fabulous appetizer before a meal. www.mtv.com /movies/news/articles/1497581/02282005/story.jhtml   (1120 words)

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