<p>To add to KB's answer:
By and large the method involves looking at the IR absorption spectrum.  If you see a set of lines which correspond to a known mineral, then you conclude that mineral is part of the asteroid's composition.  This assumes you know what's currently illuminating the asteroid (spectral irradiance).  If you're looking at the dark side, then it's a similar analysis but looking for known gaps in the not-quite-black-body exitance for a given mineral specie. </p>

CC BY-SA 3.0
2018-04-18T15:25:58.643Z
2018-04-18T15:25:58.643Z
Carl Witthoft
<p>It uses the same fundamental conept of mapping between emission-line wavelengths to certain transitions. Similar as we know that 21cm line is the transition of spin-flip of a neutral hydrogen.</p>

<p>Infrared (IR) regions is typically where the molecular lines are seen. <a href="https://en.wikipedia.org/wiki/Infrared#Spectroscopy" rel="nofollow noreferrer">Wikipedia</a> has good and brief discussion.</p>

<p>Asteriods are cold so we expect molecules to form. Therefore, we expect to see lines in IR region the most. To be more specific, surface temperature of asteriod is <a href="https://www.space.com/51-asteroids-formation-discovery-and-exploration.html" rel="nofollow noreferrer">~346 K</a>, which is equivalent to ~83714 A at max emission (assuming blackbody radiation and following Wien's law); this is IR.</p>

<p>Also note that, what we see is the surface of the asteriod, not the inside.</p>

CC BY-SA 3.0
2018-04-18T14:24:15.367Z
2018-04-18T14:24:15.367Z
Kornpob Bhirombhakdi
<p>I am trying to understand how spectrometers or spectroscopy can be used to calculate the surface composition of asteroids for the purposes of asteroid mining. </p>

<asteroids><spectroscopy><infrared>
How is IR spectroscopy used to determine the composition of asteroids?
Stuti Sharma
# How is IR spectroscopy used to determine the composition of asteroids?

(Asked by: username_0 on 2018-04-17)

I am trying to understand how spectrometers or spectroscopy can be used to calculate the surface composition of asteroids for the purposes of asteroid mining.

**Tags:** asteroids, spectroscopy, infrared

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## 2 answers

### Answer by username_1 on 2018-04-18. Score: 1

To add to KB's answer:
By and large the method involves looking at the IR absorption spectrum. If you see a set of lines which correspond to a known mineral, then you conclude that mineral is part of the asteroid's composition. This assumes you know what's currently illuminating the asteroid (spectral irradiance). If you're looking at the dark side, then it's a similar analysis but looking for known gaps in the not-quite-black-body exitance for a given mineral specie.


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### Answer by username_2 on 2018-04-18. Score: 1

It uses the same fundamental conept of mapping between emission-line wavelengths to certain transitions. Similar as we know that 21cm line is the transition of spin-flip of a neutral hydrogen.

Infrared (IR) regions is typically where the molecular lines are seen. [Wikipedia](https://en.wikipedia.org/wiki/Infrared#Spectroscopy) has good and brief discussion.

Asteriods are cold so we expect molecules to form. Therefore, we expect to see lines in IR region the most. To be more specific, surface temperature of asteriod is [~346 K](https://www.space.com/51-asteroids-formation-discovery-and-exploration.html), which is equivalent to ~83714 A at max emission (assuming blackbody radiation and following Wien's law); this is IR.

Also note that, what we see is the surface of the asteriod, not the inside.


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