Stellar Activity and Exclusion of the Outer Planet in the HD 99492 System

Abstract

A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet signatures, such as radial velocity variations that originate with the stellar surface rather than the presence of a planet. Here we present an update for the HD~99492 planetary system, using new radial velocity and photometric measurements from the Transit Ephemeris Refinement and Monitoring Survey (TERMS). Our extended time series and subsequent analyses of the Ca II H\&K emission lines show that the host star has an activity cycle of $\sim$13 years. The activity cycle correlates with the purported orbital period of the outer planet, the signature of which is thus likely due to the host star activity. We further include a revised Keplerian orbital solution for the remaining planet, along with a new transit ephemeris. Our transit-search observations were inconclusive.

arXiv comment6 pages, 3 figures, 2 tables, accepted for publication in ApJ Letters

References in corpus (31)

• Validation of the new Hipparcos reduction
• Catalog of Nearby Exoplanets
• The NASA Exoplanet Archive: Data and Tools for Exoplanet Research
• No planet for HD 166435
• Chromospheric CaII Emission in Nearby F, G, K, and M stars
• Abundances of the elements in the solar system
• Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
• Structure and Evolution of Nearby Stars with Planets II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog
• Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory
• Stellar Activity Masquerading as Planets in the Habitable Zone of the M dwarf Gliese 581
• Stellar Abundances in the Solar Neighborhood: The Hypatia Catalog
• Search for exoplanets with the radial-velocity technique: quantitative diagnostics of stellar activity
• Efficient fitting of multiplanet Keplerian models to radial velocity and astrometry data
• The NASA-UC Eta-Earth Program: I. A Super-Earth Orbiting HD 7924
• Radial Velocity Detection of Earth-mass Planets in the Presence of Activity Noise: The Case of Alpha Centauri Bb
• The Habitable Zone Gallery
• Stellar activity mimics a habitable-zone planet around Kapteyn's star
• Constraining Orbital Parameters Through Planetary Transit Monitoring
• Carbon and Oxygen in Nearby Stars: Keys to Protoplanetary Disk Chemistry
• Refining Exoplanet Ephemerides and Transit Observing Strategies
• Do stellar magnetic cycles influence the measurement of precise radial velocities?
• The Jupiter Twin HD 154345b
• The Discovery of HD 37605c and a Dispositive Null Detection of Transits of HD 37605b
• The HARPS search for southern extra-solar planets: XXVI: Seven new planetary systems
• Two Exoplanets Discovered at Keck Observatory
• Long-lived, long-period radial velocity variations in Aldebaran: A planetary companion and stellar activity
• The HD 192263 system: planetary orbital period and stellar variability disentangled
• Secretly Eccentric: The Giant Planet and Activity Cycle of GJ 328
• The Lick-Carnegie Survey: Four New Exoplanet Candidates
• Host Star Properties and Transit Exclusion for the HD 38529 Planetary System
• A vigorous activity cycle mimicking a planetary system in HD200466

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• The first super-Earth Detection from the High Cadence and High Radial Velocity Precision Dharma Planet Survey
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• Simulations for Planning Next-Generation Exoplanet Radial Velocity Surveys
• KOI-1003: A new spotted, eclipsing RS CVn binary in the Kepler field
• The multi-line slope method for the measure of the effective magnetic field of the cool stars: an application to the solar like cycle of ε Eri
• A review of planetary systems around HD 99492, HD 147379 and HD 190007 with HARPS-N
• Variability of Known Exoplanet Host Stars Observed by TESS
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• Planetary system architectures with low-mass inner planets: Direct imaging exploration of mature systems beyond 1 au
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