Sydney Jenkins

About Me

Hello! My name is Sydney Jenkins (she/her) and I am a third-year graduate student working with Prof. Andrew Vanderburg at the Massachusetts Institute of Technology. I previously earned a BA in physics and BS in computer science at the University of Chicago. My PhD research focuses on the discovery and characterization of planets around white dwarfs.

Outside of science, you can usually find me reading, hiking, or forgetting to water my plants.

Research

Searching for White Dwarf Planets

MEOW Survey

Most known exoplanets orbit stars which will eventually evolve into white dwarfs, but little is known about the fates of these systems after their hosts leave the main sequence. We aim to expand the number of known white dwarf planets. Using JWST spectroscopy, we can now identify both resolved planets (with direct imaging) and unresolved planets (by searching for infrared excesses in the white dwarf's spectrum). We are currently performing a survey of white dwarfs called the MIRI survey for Exoplanets Orbiting White Dwarfs (MEOW), led by Dr. Mary Anne Limbach.

Figure 1: False color image of a white dwarf taken with the JWST/MIRI imager.

Characterizing White Dwarf Planets

JWST Follow-Up of First Planet Transiting a White Dwarf

The first transiting planet candidate found orbiting a white dwarf, WD 1856 b, was discovered with TESS, and could play an important role in our understanding of post-main-sequence planetary evolution. However, much is still unknown about its origins, including how it reached its current orbit. The best way to distinguish between possible formation scenarios is by constraining WD 1856 b’s mass, as a lower (~1 Jupiter mass) mass would likely indicate the planet had migrated in at high eccentricity, while a larger (10-15 Jupiter masses) mass leaves common envelope evolution as a viable explanation. We identify its thermal emission with JWST/NIRSPEC spectroscopy and estimate a mass of 9 ± 4 M_Jup. Ongoing work is being done to finalize our data reductions.

Figure 2: WD 1856 b's transmission spectrum. Previous data from Spitzer is shown for comparison. With JWST, we can probe the thermal excess beyond 4 μm, indicated by the shaded region.

White Dwarf Pollution

Absence of a Correlation between White Dwarf Planetary Accretion and Primordial Stellar Metallicity (Jenkins et al. 2024)

Over a quarter of white dwarfs have photospheric metal pollution, which is evidence for recent accretion of exoplanetary material. While a wide range of mechanisms have been proposed to account for this pollution, there are currently few observational constraints to differentiate between them. To investigate the driving mechanism, we observe a sample of polluted and non-polluted white dwarfs in wide binary systems with main-sequence stars. Using the companion stars' metallicities as a proxy for the white dwarfs' primordial metallicities, we compare the metallicities of polluted and non-polluted systems. Because there is a well-known correlation between giant planet occurrence and higher metallicity (with a stronger correlation for close-in and eccentric planets), these metallicity distributions can be used to probe the role of gas giants in white dwarf accretion.

Figure 3: Metallicity distributions of white dwarf systems. Left: Metallicity distribution of polluted systems, with error bars shown in black. Middle: Metallicity distribution of non-polluted systems, with error bars shown in black. Right: CDFs of non-polluted and polluted systems, shown in orange and purple, respectively.

CV

You can find my CV here.

Last updated July, 2024.

Contact

Email

sydneyaj@mit.edu

Address

Massachusetts Institute of Technology
Deptartment of Physics
77 Massachusetts Avenue, Building 54-1715
Cambridge, MA, 02139-4307, USA

Elements

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