Eclipse Timing the Milky Way's Gravitational Potential
Publication Date
2022Journal Title
Astrophysical Journal Letters
ISSN
2041-8205
Publisher
American Astronomical Society
Volume
928
Issue
2
Language
en
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Chakrabarti, S., Stevens, D., Wright, J., Rafikov, R., Chang, P., Beatty, T., & Huber, D. (2022). Eclipse Timing the Milky Way's Gravitational Potential. Astrophysical Journal Letters, 928 (2) https://doi.org/10.3847/2041-8213/ac5c43
Abstract
We show that a small, but \textit{measurable} shift in the eclipse mid-point
time of eclipsing binary (EBs) stars of $\sim$ 0.1 seconds over a decade
baseline can be used to directly measure the Galactic acceleration of stars in
the Milky Way at $\sim$ kpc distances from the Sun. We consider contributions
to the period drift rate from dynamical mechanisms other than the Galaxy's
gravitational field, and show that the Galactic acceleration can be reliably
measured using a sample of $\textit{Kepler}$ EBs with orbital and stellar
parameters from the literature. Given the uncertainties on the formulation of
tidal decay, our approach here is necessarily approximate, and the contribution
from tidal decay is an upper limit assuming the stars are not tidally
synchronized. We also use simple analytic relations to search for well-timed
sources in the \textit{Kepler} field, and find $\sim$ 70 additional detached
EBs with low eccentricities that have estimated timing precision better than 1
second. We illustrate the method with a prototypical, precisely timed EB using
an archival \textit{Kepler} light curve and a modern synthetic \textit{HST}
light curve (which provides a decade baseline). This novel method establishes a
realistic possibility for obtaining fundamental Galactic parameters using
eclipse timing to measure Galactic accelerations, along with other emerging new
methods, including pulsar timing and extreme precision radial velocity
observations. This acceleration signal grows quadratically with time.
Therefore, given baselines established in the near-future for distant EBs, we
can expect to measure the period drift in the future with space missions like
\textit{JWST} and the \textit{Roman Space Telescope}.
Keywords
310, Galaxies and Cosmology
Sponsorship
STFC (ST/T00049X/1)
Identifiers
apjlac5c43, ac5c43, aas36601
External DOI: https://doi.org/10.3847/2041-8213/ac5c43
This record's URL: https://www.repository.cam.ac.uk/handle/1810/335731
Rights
Licence:
http://creativecommons.org/licenses/by/4.0/
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