Estimating Exoplanet Temperatures

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Discussion Overview

The discussion focuses on the methods used to estimate the temperatures of exoplanets, particularly in the context of the uncertainties involved, such as the unknown albedo and the greenhouse effect. Participants explore the theoretical underpinnings of these estimations, including the transit method and the challenges associated with measuring infrared radiation from distant exoplanets.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the meaning of estimating temperature based on light intensity and seeks clarification on the formulas and theories behind the transit method used in exoplanet observation.
  • Another participant expresses curiosity about how astronomers estimate exoplanet temperatures without knowing the albedo, emphasizing the need for more information.
  • A later reply suggests that quoted temperatures may assume zero albedo unless evidence indicates otherwise, highlighting the difficulty in obtaining necessary near-infrared data.
  • One participant argues that temperature estimates are essentially educated guesses, noting that without direct measurements from the exoplanet, conclusive methods are not possible. They also mention the potential variability due to different planetary core conditions.
  • There is a suggestion to avoid using Wikipedia as a source for research, indicating a preference for more reliable references.

Areas of Agreement / Disagreement

Participants express varying degrees of uncertainty regarding the methods of estimating exoplanet temperatures, particularly in relation to the unknown albedo. There is no consensus on the reliability of current estimation methods or the implications of assuming zero albedo.

Contextual Notes

Limitations include the dependence on assumptions about albedo and the challenges in obtaining accurate infrared data from distant exoplanets. The discussion does not resolve the complexities involved in temperature estimation.

piareround
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Recently I been reading about exoplanets on wikipedia when I came across a line that caught my idea:

It is possible to estimate the temperature of an exoplanet based on the intensity of the light it receives from its parent star. However, such estimates may be substantially in error because they depend on the planet's usually unknown albedo, and because factors such as the greenhouse effect may introduce unknown complications. A few planets have had their temperature measured by observing the variation in infrared radiation as the planet moves around in its orbit and is eclipsed by its parent star

So I started wondering exactly what did Wikipedia mean by "based on the intensity of light" and later on by "temperature measure by observing the variation in infrared radiation". I mean really how do astronomers and astrophysics find the temperatures of nearby exoplanets even though they are hundreds of parsecs away. Specifically, I really wanted to know the following two things:


1. Where kind I find more through information about theory and concepts behind the transit method of observing exoplanets? Specifically I was curious about the formulas/theory they used.
2. How does one estimate, say to the nearest hundred degrees, a exoplanet's effective temperature when the exoplanet's albedo is unknown?
 
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To be honest guys, I really am curious in trying to find out more information about how astronomers estimate the temperature of a planet if they don't know the albedo. Any information you all can find would be very helpful
 
piareround said:
To be honest guys, I really am curious in trying to find out more information about how astronomers estimate the temperature of a planet if they don't know the albedo. Any information you all can find would be very helpful

Usually things get quiet around here when no one knows the answer. I think the quoted temperatures are for zero albedo, unless there's some evidence otherwise, as getting the necessary NIR data is really hard to do.
 
qraal said:
Usually things get quiet around here when no one knows the answer. I think the quoted temperatures are for zero albedo, unless there's some evidence otherwise, as getting the necessary NIR data is really hard to do.

Plus there's been lots of atmospheric modelling to try to estimate albedos in different parts of the spectrum to see if there are observable signatures.
 
I have an answer you may not like. Any temperature estimates would be just that, educated guesses. With out actually sending measuring equipment to said Exoplanet there could be no conclusive method for exploring what the temperature would be. Perhaps there is a planet with a similar 93 billion mile buffer between it and it's parent star, but it could contain a larger or smaller molten core that would generate variant effects on the atmosphere of an unexplored planet.

Also, try omitting wikipedia from your forum vocabulary and research.
 
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