It's all just the different ways the word is used, there's nothing to worry about. Other places regard the photosphere as a shell of zero width, right where tau ~ 2/3. The quote seems to think of the photosphere as the region from the tau ~ 2/3 point to the minimum in the temperature, whereas the graph seems to think of the photosphere as something quite noticeably hotter. You can see the problem in the temperatures used in that quote- they correspond to what the graph considers to be entirely above the photosphere. Don't worry about what it says in that quote, it's all just a matter of what is meant by the "photosphere", a term that is rather vaguely defined and used to mean different things in different places. The density is what you read from the graph, correctly. The base of the photosphere (height = 0 km) is chosen to be at standard optical depth of one (i.e. See table C-4 for complete details of the Holweger-Müller model atmosphere including all depth points used.Ĩ The height scale is not arbitrary. The optical properties (such as the optical depth and the opacity) of a model atmosphere are, obviously, very important, and will be considered later. Extra points have been cubic spline interpolated by J. “The Photospheric Barium Spectrum: Solar Abundance and Collision Broadening of Ba II Lines by Hydrogen”, Solar Physics 39, pg 19-30 (1974). The 1E-06 g/cm^3 density value (plot) is more consistent with 𝜏 = 1 or "bottom" of the photosphere, while the density in the quote is more consistent with the cooler "top" of the photosphere (circa 4300 K).įrom Chapter 2: The Photosphere of Timo Nieminen's thesis Solar Line Asymmetries: Modelling the Effect of Granulation on the Solar Spectrumįigure 2-3: The Holweger-Müller Model Atmosphereħ Holweger, H. If I trace the dotted line labeled "Density" to the photosphere layer and read the density axis at the top, I read something like $8 \text^3$ in the Holweger-Müller Model Atmosphere 7.Īs pointed out in comments there is a spread in values here. The image below is found on the Wikipedia Photosphere page. I'd like to see the profile of mass density from bottom to top of the photosphere.
The Sun's photosphere contains the Sun's surface as defined by opacity = 2/3 point.
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