# Physics - Hertzsprung-Russell Diagrams

> Source: https://ollybritton.com/notes/a-level/physics/topics/hertzsprung-russell-diagrams/ · Updated: 2024-08-25 · Tags: school, physics, astrophysics, year-2

**
## Flashcards
### 2022-01-25
##### ![PHOTO HZ DIAGRAM](paste-322868cd45e25611496dd153b8df429dcb4a2f48.jpg) What is this??
A Hertzsprung-Russell diagram.

##### What is on the $x$-axis of a Hertzsprung-Russell diagram??
Temperature.

##### Which out of luminosity and temperature goes in the wrong direction on a Hertzsprung-Russell diagram??
Temperature.

##### What is on the $y$-axis of a Hertzsprung-Russell diagram??
Luminosity.

##### What is sometimes confusing about the temperature values on a Hertzsprung-Russell diagram??
They measure "effective temperature", not the temperature of the core.

##### What are the units for luminosity measured on a Hertzsprung-Russell diagram??
Solar luminosity, $L_\odot$

##### Are the scales on a Hertzsprung-Russell diagram logarithmic or linear??
Logarithmic.

##### ![PHOTO HZ BLACK](paste-3a490bae8d3cbe2485d708ed42a97ee1e28c19a8.jpg) Approximately what path will the sun trace out as it lives out its life??
![PHOTO HZ SUN PATH](paste-c8fc1c8244c35b279d074bc7c0e5f570aaa4e82c.jpg)

##### ![PHOTO HZ RED SUPERGIANTS](paste-48fa276bc46d488c4ad2b8fbd8fe2d83aef9e03a.jpg) What section is this??
Red supergiants.

##### ![PHOTO HZ RED GIANTS](paste-b214aabe24f7281f8395a3023d240dabc221cf38.jpg) What section is this??
Red giants.

##### ![PHOTO HZ WHITE DWARF](paste-e6c45ed72cbe2671fc97681cc581acbea3748c36.jpg) What section is this??
White dwarfs.

##### ![PHOTO HZ MAIN SEQUENCE](paste-b1dda2f712ac4f419d1ae0082007f8cd1fb92354.jpg) What section is this??
Main sequence stars.

##### What sort of starts does the long diagonal strip on a Hertzsprung-Russell diagram consist of??
Main sequence stars.

##### Why couldn't you place a black hole on a Hertzsprung-Russell diagram??
Because it doesn't really have a defined temperature.

### 2022-01-26
##### What is luminosity??
The total power output of a star (same as watts).

---
Olly Britton — https://ollybritton.com. Machine-readable index: https://ollybritton.com/llms.txt