El diagrama de Hertzsprung-Russell (comúnmente abreviado como diagrama H-R) es un gráfico de dispersión de estrellas indicando la relación entre las. (bg) Диаграма на Херцшпрунг-Ръсел · (ca) Diagrama de Hertzsprung-Russell · (cs) Hertzsprungův–Russellův diagram · (da). Em astronomia, o diagrama de Hertzsprung-Russell é um gráfico de distribuição que mostra a relação entre a magnitude absoluta ou luminosidade versus o.
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Historical background[ edit ] In the nineteenth-century large-scale photographic spectroscopic surveys of stars were performed at Harvard College Observatoryproducing spectral diagrama de hertzsprung-russell for tens of thousands of stars, culminating ultimately in the Henry Draper Catalogue.
File:H-R - Wikimedia Commons
In one segment of this work Antonia Maury included divisions of the stars by the width of their spectral lines. He took this as an indication of greater luminosity for the narrow-line stars, and computed secular parallaxes for several groups of these, allowing him to estimate their absolute magnitude.
The apparent magnitude of stars in the same cluster is equivalent to their absolute magnitude and so this early diagram was effectively a plot of luminosity against temperature.
The same type of diagrama de hertzsprung-russell is still used today as a means of showing the stars in clusters without having to initially diagrama de hertzsprung-russell their distance and luminosity.
Hertzsprung-Russell Diagram Explorer - Hertzsprung-Russell Diagram - NAAP
This was also the form of the diagram using apparent magnitudes of a cluster of stars all at the same distance. All forms share the same general layout: The original diagram displayed the spectral type of stars on the horizontal axis and the absolute visual magnitude on the diagrama de hertzsprung-russell axis.
The spectral type is not a numerical quantity, but the sequence of spectral types is a monotonic series that reflects the stellar surface diagrama de hertzsprung-russell.
Modern observational versions of the chart replace spectral type by a color index in diagrams made in the middle of diagrama de hertzsprung-russell 20th Century, most often the B-V color of the stars. This type of diagram is what is often called an observational Hertzsprung—Russell diagram, or specifically a color—magnitude diagrama de hertzsprung-russell CMDand it is often used by observers.
For cluster members, by assumption there is a single additive constant difference between their apparent and absolute magnitudes, called the distance modulusfor all of that cluster of stars. Early studies of nearby open clusters like the Hyades and Pleiades by Hertzsprung and Rosenberg produced the first CMDs, antedating by a few years Russell's influential synthesis of the diagram collecting data for all stars for which absolute diagrama de hertzsprung-russell could be determined.
Theoretical calculations of stellar structure and the evolution of stars produce plots that match those from observations. This type of diagram could be called temperature-luminosity diagram, but this term is hardly ever used; when the distinction is made, this form is called the theoretical Hertzsprung—Russell diagram instead.
A peculiar characteristic of this form of the H—R diagram is that the temperatures are plotted diagrama de hertzsprung-russell high temperature to low temperature, which aids in comparing this form of the H—R diagram with the observational form.
Although the two types of diagrams are similar, astronomers make a sharp diagrama de hertzsprung-russell between the two. The reason for this distinction is that the exact transformation from one to the other is not trivial. To go between effective temperature diagrama de hertzsprung-russell color requires a color—temperature relationand constructing that is difficult; it is known to be a function of stellar composition and can be affected by other factors like stellar rotation.
When converting luminosity or absolute bolometric magnitude to apparent or absolute visual magnitude, one requires a bolometric correctionwhich may or may not come from the same source as the color—temperature relation. One also needs to know the distance to the observed objects i.
Color distortion including reddening and extinction obscuration are also apparent in stars having significant circumstellar dust. The ideal of direct comparison of theoretical predictions of stellar evolution to observations thus has additional uncertainties incurred in the conversions between theoretical quantities and observations.
Diagrama de hertzsprung-russell edit ] An HR diagram with the instability strip and its components highlighted. Most of diagrama de hertzsprung-russell stars occupy the region in the diagram along the line called the main sequence.
During the stage of their lives in which stars are found on the main sequence line, they are fusing hydrogen in their cores.