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- Gyrochronology abstract "Gyrochronology is a method for estimating the age of a low-mass star like the Sun from its rotation period. The term is derived from the Greek words gyros, chronos and logos, roughly translated as rotation, age, and study respectively. It was coined in 2003 by Sydney Barnes to describe the associated procedure for deriving stellar ages, and developed extensively in empirical form in 2007.The technique builds on an insight of Andrew Skumanich,who realized that another measure of stellar rotation (v sin i) declined steadily with stellar age. Gyrochronology uses the rotation period P of the star instead of the doubly ambiguous v sin i, which depends on the unknown inclination of the star's axis of rotation, i. In particular, the technique accounts for the substantial mass dependence of stellar rotation, as exemplified by early rotation-period work on the Hyades open cluster. These two improvements are largely responsible for the precision in the ages provided by gyrochronology. The associated age estimate for a star is known as the gyrochronological age.The basic idea underlying gyrochronology is that the rotation period P, of a main-sequence cool star is a deterministic function of its age t and its mass M (or a suitable proxy such as color). The detailed dependencies of rotation are such that the periods converge rapidly to a certain function of age and mass, mathematically denoted by P = P (t, M), even though stars have a range of allowed initial periods. Consequently, cool stars do not occupy the entire 3-dimensional parameter space of (mass, age, period), but instead define a 2-dimensional surface in this space. Therefore, measuring two of these variables yields the third. Of these quantities, the mass (or a proxy such as color) and the rotation period are the easier variables to measure, providing access to the star's age, otherwise difficult to obtain.Defining a star as \"Sun-like\" is very difficult, because to be Sun-like the star should have a mass, radius, age, temperature metallicity, and spectral type that is similar to the Sun's. Measuring most of these factors is difficult, and determining the age of a star is extremely difficult, so astronomers tend to ignore it when deciding if a star is Sun-like or not. However, this is not ideal, because the Sun, and all stars change over time. If a star's rotation period is less than 25 days, the star can be determined as being younger than the Sun, if the rotation rate is longer, the star can be determined as being older than the Sun.The relationship between rotation and age was initially discovered by Soren Meibom and colleagues by measuring the period of rotation of stars in a billion-year-old cluster. Because the ages of the stars were already known, the researchers could discover a relationship between a star's age and its rotation period. A study of 30 cool stars in the 2.5-billion-year-old cluster NGC 6819 allowed to estimate the age–period relationship for older stars. Using these results, the ages of a large number of cool galactic field stars can be derived with 10% precision.".
- Gyrochronology wikiPageExternalLink index.cfm?FuseAction=ShowNews&NewsID=129.
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- Gyrochronology wikiPageLength "7215".
- Gyrochronology wikiPageOutDegree "15".
- Gyrochronology wikiPageRevisionID "671419505".
- Gyrochronology wikiPageWikiLink Ames_Research_Center.
- Gyrochronology wikiPageWikiLink Axial_tilt.
- Gyrochronology wikiPageWikiLink Category:Space_science.
- Gyrochronology wikiPageWikiLink Color_index.
- Gyrochronology wikiPageWikiLink Empirical_evidence.
- Gyrochronology wikiPageWikiLink Greek_language.
- Gyrochronology wikiPageWikiLink Hyades_(star_cluster).
- Gyrochronology wikiPageWikiLink Main_sequence.
- Gyrochronology wikiPageWikiLink Minimum_mass.
- Gyrochronology wikiPageWikiLink NASA.
- Gyrochronology wikiPageWikiLink NGC_6819.
- Gyrochronology wikiPageWikiLink Parameter_space.
- Gyrochronology wikiPageWikiLink Rotation_around_a_fixed_axis.
- Gyrochronology wikiPageWikiLink Star.
- Gyrochronology wikiPageWikiLink Stellar_rotation.
- Gyrochronology wikiPageWikiLinkText "Gyrochronology".
- Gyrochronology wikiPageWikiLinkText "gyrochronology".
- Gyrochronology wikiPageUsesTemplate Template:Cite_journal.
- Gyrochronology wikiPageUsesTemplate Template:Cite_web.
- Gyrochronology wikiPageUsesTemplate Template:Or.
- Gyrochronology wikiPageUsesTemplate Template:Refbegin.
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- Gyrochronology subject Category:Space_science.
- Gyrochronology hypernym Method.
- Gyrochronology type Software.
- Gyrochronology type Science.
- Gyrochronology comment "Gyrochronology is a method for estimating the age of a low-mass star like the Sun from its rotation period. The term is derived from the Greek words gyros, chronos and logos, roughly translated as rotation, age, and study respectively.".
- Gyrochronology label "Gyrochronology".
- Gyrochronology sameAs Q3122722.
- Gyrochronology sameAs Gyrochronologie.
- Gyrochronology sameAs Girocronología.
- Gyrochronology sameAs Gyrochronologie.
- Gyrochronology sameAs m.0gyx54h.
- Gyrochronology sameAs Q3122722.
- Gyrochronology sameAs 迴轉年代學.
- Gyrochronology wasDerivedFrom Gyrochronology?oldid=671419505.
- Gyrochronology isPrimaryTopicOf Gyrochronology.