A gas giant around Epsilon Indi !!

Detection of the closest Jovian exoplanet in the Epsilon Indi triple system
https://arxiv.org/abs/1803.08163

Quote :

We confirm the trend in the radial velocity data for Epsilon Indi A suggesting a long-period planetary companion and find significant curvature is present, sufficient to quantify Epsilon Indi Ab as a cold Jupiter with a minimum mass of 2.71+2.19−0.44 MJup on a nearly circular orbit with a semi-major axis of 12.82+4.18−0.71 au and an orbital period of 52.62+27.70−4.12 yr. We also identify other significant signals in the radial velocity data. We investigate a variety of spectral diagnostics and interpret these signals as arising from activity-induced radial velocity variations. In particular, the 2500 and 278 d signals are caused by magnetic cycles. While a planetary signal might be present in the 17.8 d signal, the origin of 17.8 and 11 d signals are most easily interpreted as arising in the rotation of the star with a period of about 35 d. We find that traditional activity indicators have a variety of sensitivities. In particular, the sodium lines and CaHK index are sensitive to all activity-induced signals. The line bisector measurement is sensitive to stellar rotation signal while Hα is sensitive to the secondary magnetic cycle. In general, because of their different sensitivities these activity indicators introduce extra noise if included in the noise model whereas differential RVs provide a robust proxy to remove wavelength-dependent noise efficiently. Based on these analyses, we propose an activity diagnostics procedure for the detection of low amplitude signals in high precision radial velocity data. Thus the Epsilon Indi system comprises of at least Epsilon Indi A, Ab as well as a long period brown dwarf binary Ba and Bb; so it provides a benchmark case for our understanding of the formation of gas giants and brown dwarfs.

The exclamation marks are more than justified. I share the joy!

Interesting, this one's been kicking around for a long time.

I note the reference they give for the age of the star doesn't appear to mention Epsilon Indi. It does give a value for Epsilon Eridani which matches the 1.4 Gyr they put in the paper though.

From what I can tell, Epsilon Indi Bab should be close to having completed a full orbit since the binarity was discovered. Hopefully there will be some new orbital elements published soon, the preliminary orbit from 2010 doesn't give values for ω or Ω.

EPE appears to have made an error of a factor of 365-or-so in the orbital period...

https://www.drewexmachina.com/2018/03/28/epsilon-indis-jovian-exoplanet/

Full story of the system on Drew ex machina

Lazarus wrote:

From what I can tell, Epsilon Indi Bab should be close to having completed a full orbit since the binarity was discovered. Hopefully there will be some new orbital elements published soon, the preliminary orbit from 2010 doesn't give values for ω or Ω.

So here's the update to the Epsilon Indi brown dwarfs (referred to here as B and C instead of Ba and Bb)

Dieterich et al. "Dynamical Masses of Eps Ind B and C: Two Massive Brown Dwarfs at the Edge of the Stellar-Substellar Boundary"
https://arxiv.org/abs/1807.09880

The masses are surprisingly high, an indication that our knowledge of the stellar/substellar boundary is incomplete.

Detection of the nearest Jupiter analog in radial velocity and astrometry data
https://arxiv.org/abs/1910.06804

Quote :

The presence of Jupiter is crucial to the architecture of the Solar System and models underline this to be a generic feature of planetary systems. We find the detection of the difference between the position and motion recorded by the contemporary astrometric satellite Gaia and its precursor Hipparcos can be used to discover Jupiter-like planets. We illustrate how observations of the nearby star ε Indi A giving astrometric and radial velocity data can be used to independently find the orbit of its suspected companion. The radial velocity and astrometric data provide complementary detections which allow for a much stronger solution than either technique would provide individually. We quantify ε Indi A b as the closest Jupiter-like exoplanet with a mass of 3 MJup on a slightly eccentric orbit with an orbital period of 45 yr. While other long-period exoplanets have been discovered, ε Indi A b provides a well constrained mass and along with the well-studied brown dwarf binary in orbit around ε Indi A means that the system provides a benchmark case for our understanding of the formation of gas giant planets and brown dwarfs.

We've got a full 3D orbit for the planet.

Mass = 3.25 M_Jup.
Period = 45.2 years.
Semi-Axis = 11.55 AU
Ecc = 0.26
Inc = 64.25
Ascending Node = 250.2
Long Peri = 77.83
Mean Anomaly = 143.8
Epoch 2448929.56

Slightly more eccentric now... will be interesting to see how future Gaia results factor into this. Would be interesting to know what the orbit of the brown dwarf binary is but that's likely going to take quite a long while.

Updated orbital parameters for both Epsilon Indi Ab and Epsilon Eridani b

Revised orbits of the two nearest Jupiters

Quote :

With its near-to-mid-infrared high contrast imaging capabilities, JWST is ushering us into a golden age of directly imaging Jupiter-like planets. As the two closest cold Jupiters, ε Ind A b and ε Eridani b have sufficiently wide orbits and adequate infrared emissions to be detected by JWST. To detect more Jupiter-like planets for direct imaging, we develop a GOST-based method to analyze radial velocity data and multiple Gaia data releases simultaneously. Without approximating instantaneous astrometry by catalog astrometry, this approach enables the use of multiple Gaia data releases for detection of both short-period and long-period planets. We determine a mass of 2.96+0.41−0.38 MJup and a period of 42.92+6.38−4.09 yr for ε Ind A b. We also find a mass of 0.76+0.14−0.11 MJup, a period of 7.36+0.04−0.05 yr, and an eccentricity of 0.26+0.04−0.04 for ε Eridani b. The eccentricity differs from that given by some previous solutions probably due to the sensitivity of orbital eccentricity to noise modeling. Our work refines the constraints on orbits and masses of the two nearest Jupiters and demonstrate the feasibility of using multiple Gaia data releases to constrain Jupiter-like planets.