Could the planets around HR 8799 be brown dwarfs?

Abstract

We consider the limiting case for orbital stability of the companions to HR 8799. This case is only consistent with ages for the system of ~100 Myr, not with the 1 Gyr age proposed from astroseismology. The discrepancy probably arises because the inclination of the star is smaller than assumed in analyzing the astroseismology data. Given this young age, the best estimates of the companion masses place them by a small margin on the planet side of the division between planets and brown dwarfs.

4 pages, 2 figures, accepted by ApJ Letters

References in corpus (5)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• HST/NICMOS detection of HR 8799 b in 1998
• Locating the planetesimals belts in the multiple-planet systems HD 128311, HD 202206, HD 82943 and HR 8799
• The dust, planetesimals and planets of HD 38529

Cited by in corpus (25)

• Spectral and Photometric Diagnostics of Giant Planet Formation Scenarios
• A Combined Subaru/VLT/MMT 1--5 Micron Study of Planets Orbiting HR 8799: Implications for Atmospheric Properties, Masses, and Formation
• Constraining the initial entropy of directly-detected exoplanets
• First Light LBT AO Images of HR 8799 bcde at 1.65 and 3.3 Microns: New Discrepancies between Young Planets and Old Brown Dwarfs
• Reconnaissance of the HR 8799 Exosolar System I: Near IR Spectroscopy
• High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood
• Atmospheric Retrieval Analysis of the Directly Imaged Exoplanet HR 8799b
• The CHARA Array Angular Diameter of HR 8799 Favors Planetary Masses for Its Imaged Companions
• Astrometric Monitoring of the HR 8799 Planets: Orbit Constraints from Self-Consistent Measurements
• Observational Constraints on Companions inside of 10 AU in the HR 8799 Planetary System
• LBT observations of the HR 8799 planetary system: First detection of HR8799e in H band
• High-Mass, Four-Planet Models for HR 8799: Constraining the Orbital Inclination and Age of the System
• Determination of the inclination of the multi-planet hosting star HR8799 using asteroseismology
• The LEECH Exoplanet Imaging Survey. Further constraints on the planet architecture of the HR 8799 system
• Alignment in star-debris disc systems seen by Herschel
• The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
• Fly-by encounters between two planetary systems II: Exploring the interactions of diverse planetary system architectures
• VLT/NACO astrometry of the HR8799 planetary system. L'-band observations of the three outer planets
• Spatially resolved submm imaging of the HR 8799 debris disk
• Long-term stability of the HR 8799 planetary system without resonant lock
• MOST light-curve analysis of the gamma Dor pulsator HR 8799, showing resonances and amplitude variations
• Theoretical seismic properties of pre-main sequence gamma Doradus pulsators
• Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star, HIP 39017
• Shaping HR8799's outer dust belt with an unseen planet
• SCExAO/CHARIS and Gaia Direct Imaging and Astrometric Discovery of a Superjovian Planet 3--4 lambda/D from the Accelerating Star HIP 54515