<p>Most of the symbols that are confusing you <em>are</em> in the Wikipedia page you link to. In columns 3, 4, and 5 are solar units: <span class="math-container">$R_{\odot}$</span> = solar radii, <span class="math-container">$L_{\odot}$</span> = solar luminosities, and <span class="math-container">$M_{\odot}$</span> = solar masses.</p>
<p>Column 6 is the <a href="https://en.wikipedia.org/wiki/Surface_gravity" rel="nofollow noreferrer">surface gravity</a> of the star, while column 7 is the age of the star (as pointed out by James K, this should read “log(t/yr)”, not “log(t/Gyr)”). I believe the surface gravities are in cgs units = cm s<span class="math-container">$^{-2}$</span> (or, more precisely, the base 10 logarithm of that), since that is mentioned in section 5.2.1 of the paper.</p>
<p>Section 6.3 of the paper describes <span class="math-container">$\tau$</span> (column 8) as the &quot;fractional main sequence age&quot;, which I assume means something like &quot;how far along in its main sequence lifetime the star is&quot;, where 0 = zero-age main sequence (just started fusing hydrogen in its core) and 1 = about to leave the main sequence.</p>
<p>Note that it is standard in astronomy papers to use <em>base 10</em> logarithms rather than natural logarithms, so &quot;log&quot; means <span class="math-container">$\log_{10}$</span>.</p>

CC BY-SA 4.0
2022-10-09T15:30:49.267Z
The ones that were confusing where "Unknown" or had (?) by them, probably didn't explain that well.  Thanks for clarifying what I didn't understand.  Is there a notation for "rotational velocity" ?
MiscellaneousUser
CC BY-SA 4.0
2022-10-09T15:47:33.213Z
HD 12446 (ALF PSC B) is 330 Myr according to https://en.wikipedia.org/wiki/Alpha_Piscium but on the table, its 8.77 Gyr, do I need to apply something to the table to get 330?  Or have I made a mistake?
MiscellaneousUser
CC BY-SA 4.0
2022-10-09T17:35:37.267Z
as noted in another question, The table has the logarithm of the age (in years, not gigayears). you need to apply "10-to-the-power" of 8.77.  it should be log(t / yr) not log t/Gyr
James K
CC BY-SA 4.0
2022-10-10T11:29:03.007Z
@JamesK Thanks for pointing that out; I’ve updated my answer accordingly.
Peter Erwin
CC BY-SA 4.0
2022-10-09T14:59:02.453Z
2022-10-10T11:28:18.210Z
2022-10-10T11:28:18.210Z
Peter Erwin
<p>I see a lot of publications where they use &quot;code&quot;/abbreviations but don't give the Laymans equivalents.  Take <a href="https://academic.oup.com/view-large/127773013" rel="nofollow noreferrer">https://academic.oup.com/view-large/127773013</a> from <a href="https://academic.oup.com/mnras/article/483/2/2300/5184501?login=false" rel="nofollow noreferrer">https://academic.oup.com/mnras/article/483/2/2300/5184501?login=false</a></p>
<p>The columns are :-</p>
<pre><code>HD 
Effective Temperature (Kelvin)
Radius (Solar Radius)
Solar Luminosity(?)
Mass (Solar Mass)
Unknown
Unknown
Age(?)
</code></pre>
<p>What are the unknown columns, am not clued up enough to copy the notation?</p>
<p>I have found <a href="https://en.wikipedia.org/wiki/List_of_common_astronomy_symbols" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/List_of_common_astronomy_symbols</a> but those above I can't find</p>
<p>If anyone knows of anywhere which explains these codes, that'll be awesome.</p>

<star><notation>
English Meaning for Abreviations (Easy Question)
MiscellaneousUser
# English Meaning for Abreviations (Easy Question)

(Asked by: username_0 on 2022-10-09)

I see a lot of publications where they use "code"/abbreviations but don't give the Laymans equivalents.  Take https://academic.oup.com/view-large/127773013 from https://academic.oup.com/mnras/article/483/2/2300/5184501?login=false
The columns are :-
HD 
Effective Temperature (Kelvin)
Radius (Solar Radius)
Solar Luminosity(?)
Mass (Solar Mass)
Unknown
Unknown
Age(?)

What are the unknown columns, am not clued up enough to copy the notation?
I have found https://en.wikipedia.org/wiki/List_of_common_astronomy_symbols but those above I can't find
If anyone knows of anywhere which explains these codes, that'll be awesome.

**Tags:** star, notation


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## 1 answers

### Answer by username_1 on 2022-10-09. Score: 6 | Accepted answer

Most of the symbols that are confusing you *are* in the Wikipedia page you link to. In columns 3, 4, and 5 are solar units: $R\_{\odot}$ = solar radii, $L\_{\odot}$ = solar luminosities, and $M\_{\odot}$ = solar masses.

Column 6 is the [surface gravity](https://en.wikipedia.org/wiki/Surface_gravity) of the star, while column 7 is the age of the star (as pointed out by username_2, this should read “log(t/yr)”, not “log(t/Gyr)”). I believe the surface gravities are in cgs units = cm s$^{-2}$ (or, more precisely, the base 10 logarithm of that), since that is mentioned in section 5.2.1 of the paper.

Section 6.3 of the paper describes $\tau$ (column 8) as the "fractional main sequence age", which I assume means something like "how far along in its main sequence lifetime the star is", where 0 = zero-age main sequence (just started fusing hydrogen in its core) and 1 = about to leave the main sequence.

Note that it is standard in astronomy papers to use *base 10* logarithms rather than natural logarithms, so "log" means $\log\_{10}$.

> **Comments:**
> **username_0**: The ones that were confusing where "Unknown" or had (?) by them, probably didn't explain that well.  Thanks for clarifying what I didn't understand.  Is there a notation for "rotational velocity" ?  
> **username_0**: HD 12446 (ALF PSC B) is 330 Myr according to https://en.wikipedia.org/wiki/Alpha_Piscium but on the table, its 8.77 Gyr, do I need to apply something to the table to get 330?  Or have I made a mistake?  
> **username_2**: as noted in another question, The table has the logarithm of the age (in years, not gigayears). you need to apply "10-to-the-power" of 8.77.  it should be log(t / yr) not log t/Gyr  
> **username_1**: @JamesK Thanks for pointing that out; I’ve updated my answer accordingly.  

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