J/AJ/162/181 RVel & Hipparcos positions of epsilon Eridani (Llop-sayson+, 2021)
Constraining the orbit and mass of epsilon Eridani b with radial velocities,
Hipparcos IAD-Gaia DR2 astrometry, and multiepoch vortex coronagraphy upper
limits.
Llop-sayson J., Wang J.J., Ruffio J.-B., Mawet D., Blunt S., Absil O.,
Bond C., Brinkman C., Bowler B.P., Bottom M., Chontos A., Dalba P.A.,
Fulton B.J., Giacalone S., Hill M., Hirsch L.A., Howard A.W., Isaacson H.,
Karlsson M., Lubin J., Madurowicz A., Matthews K., Morris E., Perrin M.,
Ren B., Rice M., Rosenthal L.J., Ruane G., Rubenzahl R., Sun H.,
Wallack N., Xuan J.W., Ygouf M.
<Astron. J., 162, 181-181 (2021)>
=2021AJ....162..181L 2021AJ....162..181L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable; Exoplanets; Spectra, optical; Spectra, infrared;
Radial velocities; Positional data
Keywords: Exoplanet astronomy; Exoplanets; Radial velocity; Astrometry
Direct imaging; Debris disks
Abstract:
εEridani is a young planetary system hosting a complex
multibelt debris disk and a confirmed Jupiter-like planet orbiting at
3.48au from its host star. Its age and architecture are thus
reminiscent of the early Solar System. The most recent study of Mawet
et al., which combined radial-velocity data and Ms-band direct imaging
upper limits, started to constrain the planet's orbital parameters and
mass, but are still affected by large error bars and degeneracies.
Here we make use of the most recent data compilation from three
different techniques to further refine εEridani b's
properties: RVs, absolute astrometry measurements from the Hipparcos
and Gaia missions, and new Keck/NIRC2 Ms-band vortex coronagraph
images. We combine this data in a Bayesian framework. We find a new
mass, Mb=0.66-0.09+0.12MJup, and inclination,
i=78.81-22.41+29.34deg, with at least a factor 2 of improvement
over previous uncertainties. We also report updated constraints on the
longitude of the ascending node, the argument of the periastron, and
the time of periastron passage. With these updated parameters, we can
better predict the position of the planet at any past and future
epoch, which can greatly help define the strategy and planning of
future observations and with subsequent data analysis. In particular,
these results can assist the search for a direct detection with JWST
and the Nancy Grace Roman Space Telescope's coronagraph instrument.
Description:
High Resolution Echelle Spectrometer (HIRES) observations were taken
using the standard iodine cell configuration used for the California
Planet Survey. Observations were taken through either the B5 or C2
decker, yielding R∼55000 spectral resolution. Spectra had a median of
293000 counts per exposure, corresponding to a median extracted flux
of 67000 counts (S/N=260) at 550nm.
Most Automatic Planet Finder (APF) measurements were acquired through
the W decker, with a spectral resolution of R∼110000. The median
exposure time across observations was 26s, yielding a per-pixel SNR of
120 at 550nm.
The Hipparcos data is generally used in its reduced form, consisting
of a five-element parameter set: the RA, DE, the proper motion (PM)
vector and, and the parallax. However, the intermediate astrometry
data (IAD) contains all individual measurements taken by the mission,
in the case of εEridani, from 1990.036 to 1992.563.
Objects:
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RA (2000) DE Designation(s) (Period)
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03 32 55.84 -09 27 29.7 epsilon Eridani = * eps Eri (P=2671d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 33 219 Radial velocities
table6.dat 42 78 Hipparcos IAD measurements
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See also:
III/150 : Perkins Revised MK Types for the Cooler Stars (Keenan+, 1989)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJ/744/138 : Calibrated visibilities of ε Eri (Baines+, 2012)
J/AJ/152/204 : HARPS-N radial velocities of HD 179070 (Lopez-Morales+, 2016)
J/A+A/623/A72 : Binarity of Hipparcos stars Gaia pm anomaly (Kervella+, 2019)
J/AJ/157/33 : Radial velocity exploration of εEridani (Mawet+, 2019)
J/AJ/158/181 : Radial velocities & S-index values for HR 5183 (Blunt+, 2019)
J/A+A/633/A110 : K band spectrum of beta Pictoris b (GRAVITY+, 2020)
J/AJ/160/207 : OSIRIS K-band spectroscopy κAndromedaeb (Wilcomb+, 2020)
J/ApJS/254/42 : Hipparcos-Gaia (EDR3) Catalog of Accelerations (Brandt, 2021)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 --- JD [2457830/2458795] Julian date of observation
14- 19 F6.2 m/s RVel [-38.8/32.4] Radial velocity
21- 25 F5.2 m/s e_RVel [0.8/39] Error on radial velocity
27- 33 A7 --- Inst Instrument used; APF or HIRES J-band
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 F8.3 yr Epoch [1990/1993] Epoch of observation
10- 25 F16.13 deg RA [52.51/52.52] Degree of right ascension
27- 42 F16.13 deg DE [-9.46/-9.45] Degree of declination
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 24-Jan-2022