The Extrasolar Planet ϵ Eridani b: Orbit and Mass
By G. Benedict, B. Mcarthur, G. Gatewood, E. Nelan, W. Cochran, A. Hatzes, M. Endl, R. Wittenmyer, S. Baliunas, G. Walker and 4 more. 2006
137 citations recorded by the source corpus.
Hubble Space Telescope (HST) observations of the nearby (3.22 pc) K2 V star ϵ Eridani have been combined with ground-based astrometric and radial velocity data to determine the mass of its known companion. We model the astrometric and radial velocity measurements simultaneously to obtain the parallax, proper motion, perturbation period, perturbation inclination, and perturbation size. Because of the long period of the companion, ϵ Eri b, we extend our astrometric coverage to a total of 14.94 yr (including the 3 yr span of the HST data) by including lower precision ground-based astrometry from the Allegheny Multichannel Astrometric Photometer. Radial velocities now span 1980.8-2006.3. We obtain a perturbation period, P = 6.85 ± 0.03 yr, semimajor axis α = 1.88 ± 0.20 mas, and inclination i = 30.°1 ± 3.°8. This inclination is consistent with a previously measured dust disk inclination, suggesting coplanarity. Assuming a primary mass M* = 0.83 M⊙, we obtain a companion mass M = 1.55MJ ± 0.24MJ. Given the relatively young age of ϵ Eri (∼800 Myr), this accurate exoplanet mass and orbit can usefully inform future direct-imaging attempts. We predict the next periastron at 2007.3 with a total separation ρ = 0.″3 at position angle P.A. = -27°. Orbit orientation and geometry dictate that ϵ Eri b will appear brightest in reflected light very nearly at periastron. Radial velocities spanning over 25 yr indicate an acceleration consistent with a Jupiter-mass object with a period in excess of 50 yr, possibly responsible for one feature of the dust morphology, the inner cavity.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/ad8a9e8c27fe4abe3fa48796f28acc578a35ab4e
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Citations in the corpus
- The planet search programme at the ESO CES and HARPS - IV. The search for Jupiter analogues around solar-like stars (2012, methodology): “We note that, combining the RVs of HARPS and all the RVs given in Benedict et al. (2006), Anglada-Escudé & Butler (2012) could also not confirm the planet solution, though, without evaluating the significance, they suggested another best fitting, similar longperiod. α Men: Eggenberger et al. (2007)…”
- Debris disc stirring by secular perturbations from giant planets (2009, background): “For the starǫ Eridani, we find that the known radial velocity planet can excite the planetesimal belt at 60 AU sufficientlyto cause destructive collisions of bodies up to 100 km in size, on a time-scale of 40 Myr.”
- A BCool magnetic snapshot survey of solar-type stars (2013, background): “…Eridani is an active K-star (K2V according to the SIMBAD data base) and a possible planet hosting star (Hatzes et al. 2000; Butler et al. 2006; Benedict et al. 2006; Anglada-Escudé & Butler 2012) and as such its magnetic field properties are of significant interest in the study of the impact…”
- Imaging Extrasolar Giant Planets (2016, background): “At 3.2 pc this star harbors the closest debris disk to the Sun, has a Jovian-mass planet detected by radial velocity and astrometric variations (Hatzes et al. 2000; Benedict et al. 2006), and possesses a long-term RV trend pointing to an additional long-period giant planet.”