Monday, April 28, 2014

Exoplanet Transits: How Our Predictions Stack Up

Compare the system parameters derived on the worksheet from the canonical values you can find online in Exoplanets.org.

Before we start, let's just take a moment to consider the fact that there's a website (actually there are several such websites) where you can look at the data on hundreds upon hundreds of exoplanets, from their mass to their radius to the properties of their orbit and parent star.

If that doesn't just blow your mind, I don't know what will.

With that out of the way, let's look at the quantities we estimated two posts ago, and how they stack up against the values found here.

Size comparison of Jupiter (L) and WASP 10b (R) (source).

We estimated $R_p$ to be 1.3 Jupiter radii; Exoplanets.org has it at 1.08 Jupiter radii (16% error).

We estimated $M_*$ to be 0.790$M_\odot$; Exoplanets.org has it at 0.790$M_\odot$ as well(!) (0% error).

We estimated $M_p$ to be 5.27 Jupiter masses; Exoplanets.org has it as 3.19 Jupiter masses (39% error).

We estimated $a/R_*$ to be 12; Exoplanets.org has it as 11.87 (0.3% error).

We estimated $T$ to be 2 hours ($7.2 \times 10^3$ seconds); Exoplanets.org has it at $8.0 \times 10^3$ seconds) (10% error).

We estimated $\rho_*$ to be 3.4 g cm$^{-3}$; Exoplanets.org has it at 1.5 g cm$^{-3}$ (130% error).

We estimated $\rho_p$ to be 2.8 g cm$^{-3}$; Exoplanets.org has it at 3.1 g cm$^{-3}$ (9% error).

These are all pretty impressively close, with a couple of exceptions (most notably the stellar density). However, even those discrepancies don't look too bad when you consider that we were working with a given stellar radius of $0.8M_\odot$--the canonical value is actually just short of $0.7 M_\odot$, which would notably improve a our value for stellar density.

All in all, a pretty impressive show for just a couple of graphs and some algebra!

1 comment:

  1. Indeed! Good job pointing out that the stellar radius will affect your results here. 4/4

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