An Infrared Optical Imaging Survey For Brown Dwarfs And Very Low Mass Stars In The Pleiades PDF Download

In this dissertation, I present a comprehensive overview of near-infrared spectroscopy and spaced-based photometric and astrometric surveys as fundamental tools for the validation and characterization of Jupiter-sized planets and brown dwarfs orbiting main sequence stars. I begin by discussing my involvement in a spectroscopic survey of planetary candidates from Kepler that leverages the efficiency and multiplexing capabilities of the northern Apache Point Observatory Galactic Evolution Experiment (APOGEE-N) spectrograph. While APOGEE-N achieves a radial velocity precision of ~100 m/s, it has facilitated a multi-visit survey of >1600 different stars. This, coupled with its near-infrared wavelength coverage, make APOGEE-N an ideal instrument to follow-up Kepler planet candidates that are expensive observations for traditional high-precision optical instruments. This program was designed to investigate a large fraction of the planetary candidates identified in Kepler and characterize the false positive scenarios that can mimic the signal of a genuine planet. I summarize the pipeline developed to reduce APOGEE-N spectra and derive radial velocities and characterize a subset of 28 low-mass companions using the public data release from this survey. I also highlight the ability of near infrared spectrometers, such as APOGEE-N, to aid in the vetting and validation of planetary systems too faint for extensive observations with single-object optical spectrographs. I then discuss my work characterizing Jupiter-sized companions to M dwarfs discovered by NASA's TESS mission using two high-precision, high-resolution spectrographs: the Habitable-zone Planet Finder (HPF) and NEID. I summarize the framework developed to vet and confirm these systems with a combination of RVs, photometry, high-contrast imaging, and astrometric measurements from Gaia. I highlight four systems discovered with TESS: (i) TOI-1899, the first M dwarf system known to have a transiting Jupiter at a period >10 days and a lucrative target for future atmospheric characterization for a temperate gas giant, (ii) TOI-3714, an M2 dwarf system with a transiting hot Jupiter and a distant white dwarf companion, (iii) TOI-3629, an M1 dwarf system hosting a transiting hot Jupiter, and (iv) TOI-2119, an M2 dwarf with a brown dwarf companion on an eccentric orbit that is an ideal target for a measurement of the projected spin-orbit misalignment with the host star. I demonstrate that the near-infrared and extended red optical wavelength coverage of HPF and NEID, respectively, enable precise mass measurements for Jupiter-sized planets and brown dwarfs orbiting M dwarfs. Lastly, I present a discussion of the changes to come with data from two all-sky surveys, TESS and Gaia, that will revolution the discovery of large companions to M dwarfs and the synergy of these discoveries with red sensitive spectrometers to enable an ensemble of well-characterized planets and brown dwarfs that are amenable to population studies and demographic analysis to constrain their origin channels.