The X-Ray Flux of HD 109833

HD 109833 is a young, G-type member of the nearby ($\sim85$ pc) 27 Myr-old moving group, MELANGE-4. The star hosts two known Super-Earth planets, with orbital periods of $9.2$ and $13.9$ days and radii of $2.9$ and $2.6$ $R_{earth}$, respectively. The planet radii are significantly smaller than most other young ($<50$ Myr) exoplanets, which typically have inflated radii and are expected to shrink by photoevaporation over time. Here we use new Chandra X-Ray Observatory observations of HD 109833 to calculate the X-ray luminosity and flux at the planets. We find that HD 109833 has lower X-ray flux than estimated based on prior limits, with a measured X-ray luminosity of $L_{x} = 10^{28.6}$ erg/s. We use this to estimate the X-Ray and UV luminosity and the resulting photoevaporative mass loss rate of the two planets. We estimate an XUV flux irradiant on the planets of $F_{XUV,b} = 1.33\times10^4$ erg/cm^2/s and $F_{XUV,c} = 6.11\times10^3$ erg/cm^2/s for planets b, and c, respectively. We compare this to other young exoplanet systems ($<50$ Myr), finding that HD 109833 has smaller planet size, and significantly lower flux irradiant on the planets, than other systems of similar age and planet separation. This suggests that stellar photoevaporation alone is not sufficient to have caused the planets' small size.