How Albedo can Help study the Composition of Exoplanets


Greetings everyone, here’s a guest post from Jonathan, who is the founder of ‘From Space with Love’, and you guys will be glad to know that this is the first guest post on our blog! I’d recommend you guys to check out his blog as he posts really good content that can help you follow your space dreams.


Image credit : NASA/JPL-Caltech

What is albedo ?

Albedo refers to the ability of a body to reflect light. This is important in astronomy because it can help us understand the composition of an object. The albedo is between 0 and 1. 0 denotes a body that absorbs all the light received in all wavelengths, and 1 would be a perfect mirror.

Two examples to understand

Ryugu, the asteroid currently explored by the Japanese space probe Hayabusa 2, has an albedo of 0.05. In other words, it looks black to us, like coal. With this information, we can already deduced that Ryugu has no ice, since ice usually has great reflective power.

 Image credit: JAXA / University of Tokyo / Kochi University / Rikkyo University / Nagoya University / Chiba Institute of Technology / Meiji University / University of Aizu / AIST.


















 At the other end of the spectrum is Enceladus, for example. This Saturn’s moon has an albedo of 0.80. It reflects a lot of light, which can be explained by the fact that its entire surface is covered with ice and snow in bright whiteness.


  Image credits : NASA/JPL/Space Science Institute


Albedo could help determine the composition of exoplanets

By measuring the albedo of exoplanets, we would have additional elements to estimate the composition of their surface or their atmosphere. But albedo alone is not enough. For example, Venus and Enceladus have close albedos for very different reasons. But combined with estimates of mass, diameter and atmospheric absorption, we could have a good idea of ?? What these worlds really look like. In rare cases, an estimate of albedo is already possible for exoplanets discovered by the transit method. The exoplanet WASP-12B is a gas giant that appears very dark. This type of measurement requires insane accuracy but could become more and more common.


Check out Jonathan’s Blog here: From Space with Love


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