Andy Skemer, Caroline Morley, myself, and the rest of the LEECH Science Team posted a paper on the arXiv today: Characterization of the Coldest Directly Imaged Exoplanet, GJ 504 b, and Evidence for Super-Stellar Metallicity.
The article, soon to be published in ApJ, describes new observations of the planet candidate discovered to orbit GJ 504 a few years ago (Kuzuhara et al., 2013). By measuring the thermal emission from the companion in three custom filters in the range 3.6--4.1 microns, we’ve made new inferences about the temperature, density, and composition of the atmosphere. The observations were made possible with LMIRCam, an AO-fed infrared camera on the Large Binocular Telescope.
I was responsible for the entirety of the data reduction, taking steps familiar to other high-contrast observers in this wavelength regime:
- Aligning and combing thousands of raw, short exposures, correcting for background sky noise and detector pattern noise
- Angular differential imaging to subtract the star (here implemented with the KLIP algorithm)
- Contrast curve calculation, PSF modeling, photometry, and error analysis
There is a lot more we could learn from the infrared SED at wavelengths redward of 4 microns. For such a faint object, however, that part of the spectrum is not likely to be accessed from the ground. Therefore, in the future GJ 504 will make an excellent target for JWST NIRCam.