Evidence for a Long-Period Planet Orbiting ϵ Eridani

By A. Hatzes, W. Cochran, B. Mcarthur, S. Baliunas, G. Walker, B. Campbell, A. Irwin, Stephenson L. S. Yang, M. Kürster, M. Endl and 3 more. 2000

198 citations recorded by the source corpus.

High-precision radial velocity (RV) measurements spanning the years 1980.8-2000.0 are presented for the nearby (3.22 pc) K2 V star ϵ Eri. These data, which represent a combination of six independent data sets taken with four different telescopes, show convincing variations with a period of ≈7 yr. A least-squares orbital solution using robust estimation yields orbital parameters of period P = 6.9 yr, velocity amplitude K = 19 m s-1, eccentricity e = 0.6, projected companion mass M sin i = 0.86 MJupiter, and semimajor axis a2 = 3.4 AU. Ca II H and K S-index measurements spanning the same time interval show significant variations with periods of 3 and 20 yr yet none at the RV period. If magnetic activity were responsible for the RV variations, then it produces a significantly different period than is seen in the Ca II data. Given the lack of Ca II variation with the same period as that found in the RV measurements, the long-lived and coherent nature of these variations, and the high eccentricity of the implied orbit, Keplerian motion due to a planetary companion seems to be the most likely explanation for the observed RV variations. The wide angular separation of the planet from the star (approximately 1'') and the long orbital period make this planet a prime candidate for both direct imaging and space-based astrometric measurements.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/12c61c13fbf85f9e326f8d9d937bc8758fd5eb19

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Detection of Earth-like Planets Using Apodized Telescopes (2001, background): “The nearby (3.2 pc) star e Eridani has recently (Hatzes et al. 2000) been reported to have a Jupiter-like planet orbiting it.”
Theoretical Spectra and Atmospheres of Extrasolar Giant Planets (2002, background): “The radial velocity detection of ǫ Eri b (Hatzes et al. 2000) is considered marginal by many, but its orbital parameters are Mpsin(i) = 0.86 MJ , a = 3.3 AU, and e ∼ 0.61, a very eccentric orbit.”
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.”
Detection of a Neptune-Mass Planet in the ρ1 Cancri System Using the Hobby-Eberly Telescope (2004, methodology): “Three sets of radial velocity data from Lick (Marcy et al. 2002), ELODIE (6) and HET were fit with a triple-Keplerian orbit using Gaussfit (5), employing the techniques to combine RV from different sources (Hatzes et al. 2000) producing the orbit of the outer planet shown in Figure 1.”
Catalog of Nearby Exoplanets (2006, unknown): “; Ga5: Galland et al. (2005); Ge5: Ge et al. (2005), http://vo.obspm.fr/exoplanets/encyclo/planet.php?p1=HD+102195&p2=b; H0: Hatzes et al. (2000); H3: Hatzes et al. (2003); Jo6: Jones et al. (2006); Jh6: J. A. Johnson et al. (2006) in prep.”
TRANSITIONAL DISKS AS SIGNPOSTS OF YOUNG, MULTIPLANET SYSTEMS (2011, background): “Indeed, gaps in debris disks surrounding main-sequence stars harbor the giant planets Fomalhaut b (Kalas et al. 2008), ǫ Eridani b (Hatzes et al. 2000), the HR 8799 system (Marois et al. 2008, 2010) and β Pictoris b (Lagrange et al. 2010).”
Limits on Planetary Companions from Doppler Surveys of Nearby Stars (2016, background): “HD 22049 (HIP 16537; programs: C, A)—ò Eridani is a young K2 dwarf that exhibits an RV period of ∼2500 days, interpretable as a Jovian-mass planet (Hatzes et al. 2000).”
Debris Disks around Sun-like Stars (2007, background): “Eri is not listedhere, but doeshaveexcess at both bands (D. E. Backman et al., in preparation) and a planet orbiting it (Hatzes et al. 2000). a This star has a known planet orbiting at 2.03 AU (Butler et al. 2006). b The first line for HD 69830 here shows our naive solution for this system, based…”
Dynamical Instabilities in Extrasolar Planetary Systems Containing Two Giant Planets (2000, background): “Additional support for a scenario based on dynamical instabilities comes from the latest detection, around the nearby K2 V star ǫ Eri: a planet with mass m sin i = 0.86 MJ, a long orbital period P = 6.9 yr (a ≃ 3.3 AU), and a large eccentricity e ≃ 0.6 (Hatzes et al. 2000).”
Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets (2016, background): “Eridani (3.2 pc) is a young star encircled by a dust ring (Greaves et al. 1998) and is one of the closest known exoplanet hosts (Hatzes et al. 2000).”
THE MUSCLES TREASURY SURVEY. I. MOTIVATION AND OVERVIEW (2016, background): “…of log10LX = 28.22 erg s −1 (Poppenhaeger et al. 2010) that grows to log10LX = 29.32 erg s −1 when the full range covered by the Chandra LETGS is included (0.07 – 2.5 keV; Ness et al. 2002). ǫ Eri hosts a ∼ 1.1 MJup planet in a 3.4 AU semi-major axis orbit (Hatzes et al. 2000; Butler et al. 2006).”
A BCool magnetic snapshot survey of solar-type stars (2013, background): “Epsilon 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…”
Stellar and substellar companions of nearby stars from Gaia DR2 (2018, background): “The massive planet Eri b (m2 = 0.86 MJ) was discovered by Hatzes et al. (2000) on an eccentric orbit (e = 0.6, r = 3.4 au).”
The Extrasolar Planet ϵ Eridani b: Orbit and Mass (2006, methodology): “Details of this analysis are given in Hatzes et al. (2000).”
The planet search programme at the ESO CES and HARPS - IV. The search for Jupiter analogues around solar-like stars (2012, background): “We cannot confirm a linear drift reported by Eggenberger et al. (2007) for α Men, neither can we confirm the planet HR 4523 b announced by Tinney et al. (2011), nor the planetǫ Eri b reported by Hatzes et al. (2000).”
Detection Limits from the McDonald Observatory Planet Search Program (2006, methodology): “Although Walker et al. (1995) did not claim any planet detections based on the CFHT data alone, two of their target objects (ǫ Eridani and γ Cephei) were subsequently found to have planetary companions when the CFHT data were combined with McDonald Observatory data (Hatzes et al. 2000, 2003).”