Physics › Equations › Astrophysics

Astrophysics equations

The 13 equations the astrophysics notes display, each with a link to the lesson that states it. Of the 13, the data booklet prints 9, 3 are yours to memorise and 1 carries no badge either way.

Year 13 · 8 lessons with equations.

The marks refer to the AQA 7408 data booklet. An equation it prints is marked as such, and one it leaves out is marked to learn. An equation with no mark has not been checked against that booklet, and some of these belong to the Edexcel, OCR or CIE specification rather than AQA’s, so check them against your own board’s data or formula booklet.

8 lessons

The astronomical refracting telescope

M = \frac{f_{o}}{f_{e}}

IN THE AQA DATA BOOKLET

Resolving power, collecting power and the CCD

\theta \approx \frac{\lambda}{D}

IN THE AQA DATA BOOKLET

\text{collecting power} \propto D^{2}

NOT IN THE AQA DATA BOOKLET: LEARN IT

The apparent magnitude scale

F = \frac{L}{4\pi d^{2}}

NOT IN THE AQA DATA BOOKLET: LEARN IT

Stellar distances and absolute magnitude

p = \frac{1}{d}

m − M = 5\,\text{log}\frac{d}{10}

IN THE AQA DATA BOOKLET

Black-body radiation and spectral classes

P = \sigma A T^{4}

IN THE AQA DATA BOOKLET

\lambda_{max} T = 2.9 × 10^{−3}\,\text{m K}

IN THE AQA DATA BOOKLET

Supernovae, neutron stars and black holes

R_{s} ≈ \frac{2GM}{c^{2}}

IN THE AQA DATA BOOKLET

The Doppler effect and red shift

f_{o} = \frac{f_{s}v}{v - v_{s}}

NOT IN THE AQA DATA BOOKLET: LEARN IT

\frac{\Delta f}{f} = \frac{v}{c}

IN THE AQA DATA BOOKLET

Approximation for v much less than c.

z = \frac{\Delta \lambda}{\lambda}

IN THE AQA DATA BOOKLET

Hubble's law and the Big Bang

v = Hd

IN THE AQA DATA BOOKLET

Every equation in the library is indexed by unit on the equation index, and the astrophysics notes are where these equations are derived and used. The 3 the booklet leaves out are on the equations to memorise, alongside the rest of the course.

Also: Engineering physics equations · Turning points equations