HIP 41378 observed by CHEOPS: Where is planet d?
arXiv:2405.20077 · doi:10.1051/0004-6361/202449689
Abstract
HIP 41378 d is a long-period planet that has only been observed to transit twice, three years apart, with K2. According to stability considerations and a partial detection of the Rossiter-McLaughlin effect, d has been determined to be the most likely orbital period. We targeted HIP 41378 d with CHEOPS at the predicted transit timing based on d, but the observations show no transit. We find that large ( hours) transit timing variations (TTVs) could explain this non-detection during the CHEOPS observation window. We also investigated the possibility of an incorrect orbital solution, which would have major implications for our knowledge of this system. If d, the periods that minimize the eccentricity would be d and d. The shortest orbital period will be tested by TESS, which will observe HIP 41378 in Sector 88 starting in January 2025. Our study shows the importance of a mission like CHEOPS, which today is the only mission able to make long observations (i.e., from space) to track the ephemeris of long-period planets possibly affected by large TTVs.
Accepted for publication in Astronomy and Astrophysics
References in corpus (22)
- The PLATO 2.0 Mission
- The CHEOPS mission
- Expected performances of the Characterising Exoplanet Satellite (CHEOPS) III. Data reduction pipeline: architecture and simulated performances
- Investigations of approximate expressions for the transit duration
- Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops
- Five Planets Transiting a Ninth Magnitude Star
- TRADES: A new software to derive orbital parameters from observed transit times and radial velocities. Revisiting Kepler-11 and Kepler-9
- HARPS-N radial velocities confirm the low densities of the Kepler-9 planets
- Can planetary rings explain the extremely low density of HIP 41378f?
- Uncovering the true periods of the young sub-Neptunes orbiting TOI-2076
- The First Near-Infrared Transmission Spectrum of HIP 41378 f, a Low-Mass Temperate Jovian World in a Multi-Planet System
- A Discrete Set of Possible Transit Ephemerides for Two Long Period Gas Giants Orbiting HIP 41378
- Revisiting the HIP41378 system with K2 and Spitzer
- A transit timing variation observed for the long-period extremely low density exoplanet HIP 41378f
- TOI-5678 b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS
- Two Warm Neptunes transiting HIP 9618 revealed by TESS & Cheops
- Asteroseismology of the Multiplanet System K2-93
- Oblique rings from migrating exomoons: A possible origin for long-period exoplanets with enlarged radii
- Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
- Rossiter-McLaughlin detection of the 9-month period transiting exoplanet HIP41378 d
- Refined parameters of the HD 22946 planetary system and the true orbital period of planet d
- TESS and CHEOPS Discover Two Warm Sub-Neptunes Transiting the Bright K-dwarf HD 15906