My research focuses on designing and building instruments that characterize exoplanetary systems.
I am currently a 51 Pegasi b Postdoctoral Fellow in the astronomy department at Caltech. I am a team member of PARVI and KPF, which are next-generation radial velocity (RV) spectrographs that will measurement the "wobble" of a star due to gravitational tugs from a planetary companion, which can be related to the planet masses. Many sources of noise can pose a challenge to measuring the masses of smaller, rocky planets that are the best candidates for habitability. My work centers around (1) improving removing absorption features due to Earth's atmosphere in the spectra used to make RV measurements and (2) building stellar activity monitoring instruments so we can remove stellar noise sources from the exoplanetary signal. I am also interested in characterizing exoplanet atmospheres with high resolution transmission spectroscopy as well as designing better ways to perform ground-based low resolution transmission spectroscopy to probe the atmospheres of hot Jupiters.
Recent and Ongoing Work
Stellar Activity Monitoring for KPF
I am the lead on designing and building the Ca H&K activity monitoring spectrograph for the Keck Planet Finder (KPF). This R~12,000 auxiliary spectrograph will observe simultaneous with KPF. By decoupling the UV spectral coverage from the main spectrograph into a separate instrument, KPF can achieve higher throughput over all parts of the spectrum.
Telluric Correction of Stellar FTS Spectra
I developed a semi-empirical method for correcting tellurics in high SNR, R~106 Solar spectra to create a new Solar atlas from 0.5-1um. The atlas along with the extracted telluric spectra are available for download here. This model avoids molecular line list errors and can be useful for RV spectra well-sampled in airmass, and works well even when barycentric motion is poorly sampled.
I have been using the Planetary Spectrum Generator to model telluric lines in effort to validate HITRAN line lists.
The Oxyometer: High resolution imaging for studying exoplanet atmosphere
Using a Fabry-Perot filter, I developed an instrument that allows for simultaneous narrowband imaging over two adjecent ~0.3nm filter bands. The instrument worked well on-sky and provides a high throughput, low systematics instrument for detection of strong bandheads or absorption features in exoplanet atmospheres through transmission spectroscopy. Although detection of O2 in Earth-like planets using such an instrument (Baker+2019) would require large apertures in space and be limited to M dwarf host stars, I am exploring the application of this instrument to the detection of alkali metals in hot Jupiter atmospheres.
Get In Touch
abaker [at] caltech.edu
Cahill Center for Astronomy & Astrophysics
1216 East California Boulevard
Pasadena, CA 91125