One of the most useful and powerful plots in astrophysics is the Hertzsprung-Russell diagram (hereafter called the H-R diagram). It originated in 1911 when the Danish astronomer,
Ejnar Hertzsprung
, plotted the absolute magnitude of stars against their colour (hence effective temperature).
Who were the two astronomers who developed the HR diagram?
Developed independently in the early 1900s by
Ejnar Hertzsprung and Henry Norris Russell
, it plots the temperature of stars against their luminosity (the theoretical HR diagram), or the colour of stars (or spectral type) against their absolute magnitude (the observational HR diagram, also known as a colour-magnitude …
What does H stand for in an HR diagram?
The
Hertzsprung–Russell diagram
, abbreviated as H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars’ absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
Who invented the HR diagram?
Of great importance to theories of stellar evolution, it evolved from charts begun in 1911 by
the Danish astronomer Ejnar Hertzsprung and independently by the U.S. astronomer Henry Norris Russell
.
Who is the HR diagram named after?
Such a plot was first made by two astronomers working independently:
Ejnar Hertzsprung (Denmark) and Henry Norris Russell
(Princeton, USA). This kind of diagram was named after them, as the Hertzsprung-Russell Diagram, or H-R Diagram.
How was the HR diagram created?
It originated in 1911 when
the Danish astronomer, Ejnar Hertzsprung, plotted the absolute magnitude of stars against their colour
(hence effective temperature). Independently in 1913 the American astronomer Henry Norris Russell used spectral class against absolute magnitude.
What type of star is the sun on the HR diagram?
Explanation: Sun is a
main sequence star
. See HR diagram.
Which color star is hottest?
White stars are hotter than red and yellow.
Blue stars
are the hottest stars of all.
Where is Deneb on the HR diagram?
In looking at the H-R Diagram on the right, we can see the sun in the main sequence towards the middle while Deneb is
located at the top (circled)
as the two are in very different stages of their lives.
Where is a red giant on the HR diagram?
Red giants are found
top right hand side of
H R diagram.
Why was the H-R diagram created?
The Hertzsprung-Russell diagram is a
graph that plots the temperature of a star against its absolute magnitude or luminosity
. It was created by astronomers Ejnar Hertzsprung and Henry Norris Russell about 1910, and can be used to chart the life cycle or evolution of a star.
What is star life cycle?
A star’s life cycle is
determined by its mass
. The larger its mass, the shorter its life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born.
Which star has the highest luminosity?
| Name Constellation Bolometric luminosity (Solar lum.) | Sun 1 | Alpha Centauri A Centaurus 1.519 | Sirius Canis Major 25.4 | Vega Lyra 40.12 |
|---|
How do you draw a star on an H-R diagram?
A Simple H-R Diagram. Once you
know the luminosity
and temperature (or color) of a star, you can plot the star as a point on the H-R diagram. Plot the luminosity on the y-axis with brighter stars going toward the top.
Where are the largest stars located on an H-R diagram?
The model stars with the largest masses are the hottest and most luminous, and they are located
at the upper left of the diagram
. The least-massive model stars are the coolest and least luminous, and they are placed at the lower right of the plot.
