Discussion Overview
The discussion revolves around the calculation of a planet's radius using the apparent luminosity of a star, particularly in the context of exoplanet detection methods. Participants explore the theoretical framework for understanding how a planet obscures a star's light and the implications for measuring luminosity and radius.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
- Mathematical reasoning
Main Points Raised
- One participant proposes a method to calculate a planet's radius based on the dimming of a star's luminosity when the planet transits in front of it, suggesting that the apparent luminosity decreases due to the obscured area.
- Another participant mentions that current methods of detecting exoplanets rely on similar principles and that astronomers have confidence in these methods.
- A later reply emphasizes the importance of using the observed flux and area of the stellar disc rather than the total luminosity and area of the star, arguing that only the disc is observed during a transit.
- Some participants discuss the relationship between the area of the planetary disc and the total luminosity of the star, questioning how much luminosity is actually obscured during a transit.
- There is a contention regarding the percentage of luminosity blocked by the planet, with some arguing it cannot be simply calculated as a fraction of the star's total area.
- One participant clarifies that the proportion of luminosity blocked depends on the distance of the planet from the star, noting that a planet further away will block less luminosity.
- Another participant attempts to reconcile their formula with the observed effects, suggesting that if the planet's radius equals the star's radius, the luminosity reduction could be around 25%.
- Disagreement arises over the interpretation of the radius and the conditions under which the calculations hold true, with some participants challenging the assumptions made in earlier posts.
Areas of Agreement / Disagreement
Participants express differing views on the correct approach to calculating the impact of a planet on a star's luminosity. There is no consensus on how to interpret the calculations or the assumptions involved, indicating ongoing debate and uncertainty.
Contextual Notes
Limitations include the dependence on definitions of luminosity and flux, as well as the unresolved mathematical relationships between the areas involved in the calculations. The discussion highlights the complexity of modeling such astronomical phenomena.
