Curve on the Hertzsprung-Russell diagram representing stars of a particular age
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Theoretical isochrones for near-solar metallicity and a range of ages
In stellar evolution, an isochrone is a curve on the Hertzsprung-Russell diagram, representing a population of stars of the same age but with different mass.[1]
The Hertzsprung-Russell diagram plots a star's luminosity against its temperature, or equivalently, its color. Stars change their positions on the HR diagram throughout their life. Newborn stars of low or intermediate mass are born cold but extremely luminous. They contract and dim along the Hayashi track, decreasing in luminosity but staying at roughly the same temperature, until reaching the main sequence directly or by passing through the Henyey track. Stars evolve relatively slowly along the main sequence as they fuse hydrogen, and after the vast majority of their lifespan, all but the least massive stars become giants. They then evolve quickly towards their stellar endpoints: white dwarfs, neutron stars, or black holes.
Isochrones can be used to date open clusters because their members all have roughly the same age.[2] One of the first uses of an isochrone method to date an open cluster was by Demarque and Larson in 1963.[3] If the initial mass function of the open cluster is known, isochrones can be calculated at any age by taking every star in the initial population, using numerical simulations to evolve it forwards to the desired age, and plotting the star's luminosity and magnitude on the HR diagram.[4] The resulting curve is an isochrone, which can be compared against the observational color-magnitude diagram to determine how well they match. If they match well, the assumed age of the isochrone is close to the actual age of the cluster.
^Cite error: The named reference Kippenhahn2012 was invoked but never defined (see the help page).
^Cite error: The named reference Frebel2015 was invoked but never defined (see the help page).
^Cite error: The named reference DemarqueAndLarson1963 was invoked but never defined (see the help page).
^Cite error: The named reference Friel1995 was invoked but never defined (see the help page).
In stellar evolution, an isochrone is a curve on the Hertzsprung-Russell diagram, representing a population of stars of the same age but with different...
Look up isochrone in Wiktionary, the free dictionary. Isochrone may refer to: Stellarisochrone, the curve on the Hertzsprung–Russell diagram representing...
Stellar isochroneStellar kinematics Stellar limb-darkening Stellar luminosity Stellar magnetic field Stellar magnitude Stellar mass Stellar mass black...
200510440. Lejeune, T; Schaerer, D (2001). "Database of Geneva stellar evolution tracks and isochrones for ( U B V ) J ( R I ) C J H K L L ′ M {\displaystyle...
diagram. Hayashi track Henyey track Pre-main-sequence star Protostar Stellarisochrone T Tauri star Stahler, S. W. (1983). "The Birthline for Low-Mass Stars"...
the evolutionary tracks and isochrones (luminosity-temperature distributions of stars at a given age) for a variety of stellar masses and noted that NGC2264...
Gliese 367 b, c & d. Gliese 367's age is unclear. Modelling using stellarisochrones gives a young age of less than 60 million years old, but its orbit...
it reaches the main sequence. Stellar evolution Stellar birthline Stellarisochrone Iben, Icko, Jr. (1965-04-01). "Stellar Evolution. I. The Approach to...
the main sequence is a classification of stars which appear on plots of stellar color versus brightness as a continuous and distinctive band. Stars on...
has the most-cited research papers of any astronomer in Canada. His stellarisochrones resulting from his models are widely used throughout the world. "Canadian...
used to build isochrones by putting curves through equal-age points along the tracks. When the mass of a star can be determined, an isochrone can be used...
S.; Smirnov, Anton A.; Usachev, Pavel A.; Poliakov, Denis M. (2021). "Isochrone fitting of Galactic globular clusters – III. NGC 288, NGC 362, and NGC...
36 Gyr and 3.75 Gyr, respectively. Finally the age estimates using the isochrone method, which involve fitting the stars to evolutionary models, yield...
Bressan, A.; Bertelli, G.; Chiosi, C. (2000). "Evolutionary tracks and isochrones for low- and intermediate-mass stars: From 0.15 to 7 M?, and from Z=0...
and more luminous. Based on asteroseismic density constraints and stellarisochrones, it was found that the age is 3.37 +0.20 −0.47 billion years making...
S.; Smirnov, Anton A.; Usachev, Pavel A.; Poliakov, Denis M. (2021). "Isochrone fitting of Galactic globular clusters – III. NGC 288, NGC 362, and NGC...
Bressan, A.; Bertelli, G.; Chiosi, C. (2000). "Evolutionary tracks and isochrones for low- and intermediate-mass stars: From 0.15 to 7 Msun, and from Z=0...
Melotte 111, but its proper motion and isochrone are inconsistent. Alpha Persei Cluster List of nearby stellar associations and moving groups "Cl Melotte...
towards a red giant. Its radius is either 6.5 R☉ (estimated using stellarisochrones) or 7 R☉ (measured). The star is emitting a luminosity equivalent...
diagram populated by evolved cool luminous stars. This is a period of stellar evolution undertaken by all low- to intermediate-mass stars (about 0.5...
2006. Retrieved 3 January 2007. Siess, Lionel (2000). "Computation of Isochrones". Institut d'Astronomie et d'Astrophysique, Université libre de Bruxelles...
Bressan, A.; Chiosi, C.; Fagotto, F.; Nasi, E. (August 1994). "Theoretical isochrones from models with new radiative opacities". Astronomy and Astrophysics...
Barnes (2001). "Toward Better Age Estimates for Stellar Populations: The Y 2 {\displaystyle Y^{2}} Isochrones for Solar Mixture". Astrophysical Journal Supplement...
variety of methods. All rely on fitting the observed stars to a curve (an isochrone) on a color-magnitude diagram (CMD), then comparing the luminosity of...
Bressan, A.; Chiosi, C.; Fagotto, F.; Nasi, E. (August 1994). "Theoretical isochrones from models with new radiative opacities". Astronomy and Astrophysics...
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