I’ve adopted Kenneth Lang’s Essential Astrophysics for my ASTRO 320 class at U. Alberta this year. It has the wonderful feature of being relatively low cost owing to the University Library subscribing to the Springer eBooks. Thanks, Library. Unfortunately, the book is a First Edition. As such there are typos. Here is a list of the ones we’ve found so far.

Section 2.4, Page 45

The Planck function (Eq. 2.17) is given as

$$B_\nu(\nu,T) = \frac{2h\nu^3}{c^2}\frac{1}{\exp\left[h\nu/(kT)-1\right]}$$

where it should be

$$B_\nu(\nu,T) = \frac{2h\nu^3}{c^2}\frac{1}{\exp [h\nu/(kT)]-1}.$$

Section 2.4, Page 45

The value of $\pi$ is given as 3.13159 and should be 3.14159.

Section 2.4, Page 46

The Planck function (Eq. 2.18) is given as

$$B_\lambda(\lambda,T) = \frac{2h c^2 }{\lambda^5}\frac{1}{\exp\left[hc/(\lambda kT)-1\right]}$$

where it should be

$$B_\lambda(\lambda,T) = \frac{2hc^2}{\lambda^5}\frac{1}{\exp [hc/(\lambda kT)]-1}.$$

Section 2.4, Page 48

The radiation energy (Eq. 2.23) density

$$u_\nu(T) = \frac{8\pi \nu^2}{c^3}\frac{1}{\exp\left[\left(\frac{h\nu}{kT}\right)-1\right]}$$

should read

$$u_\nu(\nu, T) = \frac{8\pi\nu^2}{c^3}\frac{1} {\exp\left(\frac{h\nu}{kT}\right)-1}$$

Section 2.4, Page 49

Above Equation 2.29, the text says “energy flowing out of the blackbody over $\pi$ sr, or over the hemisphere facing an observer.”

A hemisphere is $2\pi$ sr, but the equation is correct. The “missing” factor of $1/2$ comes from the shrinking projected size of the differential area at larger angles.

Section 2.4, Page 50

The Stefan-Boltzmann Constant is given as $5.6704\times 10^{-8}\mathrm{~W~m^{-2}~K^{4}}$ and it should be $5.6704\times 10^{-8}\mathrm{~W~m^{-2}~K^{-4}}$. (Thank you Tanner S.)

Focus 2.5, Page 59

Dr. Hans Seuss died in 1993 not 1920, which makes his story a lot less about tragic death at an early age. (Thanks to Paul).

Section 5.4.1, Page 141

The book gives the solar wind pressure as a “startling $10^{18}$ Pa,” which would be truly startling and would also deliver enough energy to destroy the planet in a year. The actual numbers that NOAA bandies about are closer to $2\times 10^{-9}$ Pa.

Section 6.3, Page 174

Boltzmann was born in 1844 not 1894, which Michelle S. noted the date in the text would be hard to reconcile with Boltzmann deriving his eponymous distribution in 1872.

Section 8.3.3, Page 232

An MeV is $1.602\times 10^{-13}\mbox{ J}$ not 1.692 as given at the bottom of the page.

Section 10.1.2, Page 296

The magnitude system is defined so that an interval of five magnitudes correspond to exactly a factor of 100 in brightness. Thus, Equation 10.4 should read

$$m_1 - m_2 = -2.5 \log_{10}\left(\frac{f_1}{f_2}\right) = 2.5 \log_{10}\left(\frac{f_2}{f_1}\right)$$

Section 10.5.6, Page 354

The first generation of stars is broadly described as Population III and theoretically had $Z=0$. The second, slightly enriched generation was called Population II, which are relatively metal-poor compared to most stars ($Z\sim 10^{-3}$). Finally, most stars seen today have roughly solar metallicity ($Z\sim 0.02$) and are called Population I.