How to use the Binary Mass Function for exoplanets?

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Discussion Overview

The discussion revolves around the calculation of the mass of the exoplanet KELT-8b using the binary mass function and radial velocity values. Participants explore the definitions, units, and methods involved in these calculations, focusing on the challenges faced in interpreting the data and applying the binary mass function in the context of exoplanet research.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant expresses confusion about the binary mass function and its units, noting a discrepancy between their calculated mass and the mass reported in existing literature.
  • Another participant suggests a method for finding definitions in scientific papers, emphasizing the importance of referencing related literature.
  • A participant clarifies that while they understand the definitions of radial velocity values, they are uncertain about the binary mass function's application and units.
  • Concerns are raised about the lack of a definition for the binary mass function in the cited paper, prompting questions about its source and interpretation.
  • A participant explains that the binary mass function is intended to constrain the mass of an unseen component in a binary system, but they struggle with condensing radial velocity values into a single measurement for calculations.
  • There is mention of averaging the highest radial velocity values, with uncertainty expressed about the potential impact of this method on the accuracy of the results.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definition or application of the binary mass function, and multiple competing views on how to interpret and calculate the mass from radial velocity data remain unresolved.

Contextual Notes

Participants highlight limitations in the definitions provided in the literature and the potential for misinterpretation of radial velocity data. There is also an acknowledgment of the need for clarity regarding the units used in the binary mass function.

Who May Find This Useful

This discussion may be useful for students and researchers interested in exoplanet mass calculations, the application of the binary mass function, and the interpretation of radial velocity data in astrophysics.

Astroxzip
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TL;DR
Hi. I am working on a research paper for my high school and I am trying to calculate the mass of an exoplanet using the radial velocity values of its star. However, I am confused as to the binary mass function and what units you would use. I also wanted to know how you would interpret a radial velocity curve to calculate the mass of the exoplanet. Thank you
The paper I am using for my radial velocity values is the following (Table 4)
https://iopscience.iop.org/article/10.1088/0004-637X/810/1/30
Hi. I am working on a research paper for my high school and I am trying to calculate the mass of KELT-8b using the radial velocity values of its star. However, I am confused as to the binary mass function and what units you would use. I was under the impression you would use solar masses however I am getting a mass of 3.48 solar masses which is nothing close to the mass they found in the paper. I also wanted to know how you would interpret a radial velocity curve to calculate the mass of the exoplanet because I figured maybe I found the radial velocity the wrong way. The way I did it was by taking an average of the peaks after graphing it against the time. Thank you
The paper I am using for my radial velocity values is the following (Table 4)
https://iopscience.iop.org/article/10.1088/0004-637X/810/1/30
 
Last edited:
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Here is how to find how something is defined in a scientific paper.
  1. Look for a definition in the paper.
  2. If there is no definition, look for a reference to what you are looking for. Get that paper.
  3. Look for a definition in that paper.
  4. Repeat as needed.
 
Vanadium 50 said:
Here is how to find how something is defined in a scientific paper.
  1. Look for a definition in the paper.
  2. If there is no definition, look for a reference to what you are looking for. Get that paper.
  3. Look for a definition in that paper.
  4. Repeat as needed.
Hi. I know how they have defined the radial velocity values. The problem is I do not know how the binary mass function works and what units you need for the function.
 
The phrase "binary mass function" does not appear in the paper you cite. Where did you come across the term and how is it defined?
 
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Ibix said:
The phrase "binary mass function" does not appear in the paper you cite. Where did you come across the term and how is it defined?
Ok so, basically the paper I am writing needs me to calculate the mass using radial velocity method. After doing some research, I found the binary mass function in an Astrophysics textbook which I found could work for exoplanets. However the problem is that the units are not defined anywhere which is the main source of issue. As for how it is defined, the binary mass function constrains the mass of the unseen component of a binary system, which in my case is the mass. As for the paper I cited, I used it for the values of the radial velocity, however I am struggling a bit to understand how to condense them into one for my calculations. I ended up taking an average of the five highest values however I think my answer could have deviated due to the method I chose to condense the radial velocity values into one.
 

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