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Questions tagged [absolute-magnitude]

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Is albedo ever greater than unity? How is it calculated for various surface diffusivities and specular reflection? [duplicate]

I'm trying to understand how albedo would be calculated for a body with well-characterized surface reflectance properties, so that it's absolute magnitude could be defined. One could argue that this ...
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2answers
86 views

Conversion of UBVRIJHK magnitudes to luminosity?

So, I know that the standard for conversion from bolometric magnitude to luminosity established in 2015 equates to: L = 10^(-0.4 * magnitude) * 3.0128e28 Easy ...
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1answer
100 views

Absolute magnitudes with dust extinction

I have a distant $z\sim3$ galaxy with absolute AB magnitudes $M_B$ and $M_I$, where the central wavelengths of the $B$ and $I$ passbands are $\sim0.4\,\mu\text{m}$ and $\sim0.8\,\mu\text{m}$, ...
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In the JPL small body browser, why is uncertainty on absolute magnitude “N/A”?

In the JPL small body browser, orbital elements are all provided with uncertainties and even a covariance matrix, such as for 2013 LA2. Very good. But underneath, the absolute magnitude is reported ...
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0answers
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Error bar in Python [closed]

I have two column data as magnitude and period of several stars. I have plotted magnitude vs. period, but I need to add a column as error bar for Y values. How can I write the code to put the error ...
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1answer
177 views

Gaia Gbp - Grp: why does it get larger as star gets redder?

As an enthusiastic amateur scientist, I'm plowing my way through a cool Gaia DR2-based paper, "An Empirical Measurement of the Initial-Final Mass Relation with Gaia White Dwarfs". I'm doing all right, ...
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1answer
87 views

Good source for the relationship between absolute magnitude, diameter, and albedo?

In this answer I have rearranged an equation from somewhere, and now I can not relocate the source. My re-aranged form is: $$M_{Abs} = 5 \left(\log_{10}(1329) -\frac{1}{2}\log_{10}(\text{albedo}) -\...
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Is there an acceptable value for the absolute magnitude of horizontal branch stars?

I'm writing a test for a gen-ed level astronomy class that I teach, and would just like a good reliable number to use as the basis for a distance calculation question. And yes, I know that real ...
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1answer
56 views

Mass-magnitude relation of evolved stars

In short: what mass is appropriate for absolute magnitude $M_V \sim -7$? Some context: I'm processing the observational data (supernova light curve) and curve fitting gives me about $0.4M_\bigodot$ ...
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1answer
1k views

How to calculate luminosity in g-band from absolute AB magnitude and luminosity distance?

How can I calculate the (non-bolometric) luminosity $L$ of a galaxy (or a star for that matter) over a given band from its AB apparent magnitude $m_{AB}$ over that band and its luminosity distance $...
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2answers
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Calculating star radius from temperature and absolute magnitude - what am I missing?

In an attempt to visualise nearby stars, I've tried to get the star radius (measured in solar radii) using the equation provided on the following site: http://cas.sdss.org/dr4/en/proj/advanced/hr/...
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1answer
667 views

How to find a Cepheid's pulsation period using its graph?

Basically, I've been seeing these graphs that say: Cepheid Period-Luminosity Relation and the Period axis is supposed to be "logarithmic"; How does this graph work? Since the luminosity of a star ...
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3answers
5k views

Is the Sun visible from Proxima Centauri to human eyes?

I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
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2answers
1k views

Table of absolute magnitudes of stars by spectral type and photometric band

I would like to find a table where I can, say, look for K5 dwarfs and read off that stars of that type have on average an absolute magnitude of X.XX in the infrared L band and Y.YY in the G band. I've ...
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1answer
86 views

Absolute/apparent magnitude and distance for HIP31978 inconsistent?

EDIT: I am still following up, but here's the latest response from Wolfram: Paclet servers are updated and optimized for each version of Mathematica, so I suspect you may be working on an older ...