Utilizing a global network of telescopes to update the ephemeris for the highly eccentric planet HD 80606 b and to ensure the efficient scheduling of JWST

Abstract

The transiting planet HD80606b undergoes a 1000-fold increase in insolation during its 111-day orbit due to it being highly eccentric (e=0.93). The planet's effective temperature increases from 400K to over 1400K in a few hours as it makes a rapid passage to within 0.03AU of its host star during periapsis. Spectroscopic observations during the eclipse (which is conveniently oriented a few hours before periapsis) of HD80606b with the James Webb Space Telescope (JWST) are poised to exploit this highly variable environment to study a wide variety of atmospheric properties, including composition, chemical and dynamical timescales, and large scale atmospheric motions. Critical to planning and interpreting these observations is an accurate knowledge of the planet's orbit. We report on observations of two full-transit events: 7 February 2020 as observed by the TESS spacecraft and 7--8 December 2021 as observed with a worldwide network of small telescopes. We also report new radial velocity observations which when analyzed with a coupled model to the transits greatly improve the planet's orbital ephemeris. Our new orbit solution reduces the uncertainty in the transit and eclipse timing of the JWST era from tens of minutes to a few minutes. When combined with the planned JWST observations, this new precision may be adequate to look for non-Keplerian effects in the orbit of HD80606b.

Accepted for publication in AJ; in press

References in corpus (11)

• The Transiting Exoplanet Survey Satellite
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• The GROWTH Marshal: A Dynamic Science Portal for Time-Domain Astronomy
• Photometric and spectroscopic detection of the primary transit of the 111-day-period planet HD 80606 b
• High eccentricity planets from the Anglo-Australian Planet Search
• A Search for Multi-Planet Systems Using the Hobby-Eberly Telescope
• Detection of a transit by the planetary companion of HD 80606
• ExoClock Project: An open platform for monitoring the ephemerides of Ariel targets with contributions from the public
• Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems
• Discovery of the secondary eclipse of HAT-P-11 b
• The California Legacy Survey I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades

Cited by in corpus (5)

• A 16 Hour Transit of Kepler-167 e Observed by the Ground-based Unistellar Telescope Network
• Seasonal Changes in the Atmosphere of HD 80606b Observed with JWST's NIRSpec/G395H
• On the follow-up efforts of long-period transiting planet candidates detected with Gaia astrometry
• TrES-1 b: A Case Study in Detecting Secular Evolution of Exoplanet Orbits
• Examining the detectability of ringing on highly eccentric exoplanets