J/AJ/161/179 Predicted positions of βPictoris b and c (Brandt+, 2021)
Precise dynamical masses and orbital fits for βPic b and βPic c.
Brandt G.M., Brandt T.D., Dupuy T.J., Li Y., Michalik D.
<Astron. J., 161, 179-179 (2021)>
=2021AJ....161..179B 2021AJ....161..179B (SIMBAD/NED BibCode)
ADC_Keywords: Exoplanets; Positional data; Infrared
Keywords: Exoplanet astronomy; Exoplanet dynamics; Exoplanet systems
Exoplanet formation; Radial velocity; Pulsating variable stars
Brown dwarfs; Exoplanet evolution
Abstract:
We present a comprehensive orbital analysis to the exoplanets
βPictoris b and c that resolves previously reported tensions
between the dynamical and evolutionary mass constraints on βPicb.
We use the Markov Chain Monte Carlo orbit code orvara to fit 15years
of radial velocities and relative astrometry (including recent GRAVITY
measurements), absolute astrometry from Hipparcos and Gaia, and a
single relative radial velocity measurement between βPic A and b.
We measure model-independent masses of 9.3-2.5+2.6MJup for
βPicb and 8.3±1.0MJup for βPicc. These masses are
robust to modest changes to the input data selection. We find a
well-constrained eccentricity of 0.119±0.008 for βPicb, and
an eccentricity of 0.21-0.09+0.16 for βPicc, with the two
orbital planes aligned to within ∼0.5°. Both planets' masses are
within ∼1σ of the predictions of hot-start evolutionary models
and exclude cold starts. We validate our approach on N-body synthetic
data integrated using REBOUND. We show that orvara can account for
three-body effects in the βPic system down to a level ∼5 times
smaller than the GRAVITY uncertainties. Systematics in the masses and
orbital parameters from orvara's approximate treatment of multiplanet
orbits are a factor of ∼5 smaller than the uncertainties we derive
here. Future GRAVITY observations will improve the constraints on
βPicc's mass and (especially) eccentricity, but improved
constraints on the mass of βPicb will likely require years of
additional radial velocity monitoring and improved precision from
future Gaia data releases.
Description:
There are several sources and numerous measurements of relative
astrometry for βPicb, and three recent measurements for
βPicc. We use all relative astrometry, which is comprised of
measurements from Near-Infrared Coronagraphic Imager (NICI) on
Gemini-South, NACO on the Very Large Telescope (VLT), MagAO on
Magellan, Gemini Planet Imager (GPI) on Gemini South,
Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) on the
VLT, and GRAVITY on the VLT.
Objects:
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RA (2000) DE Designation(s)
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05 47 17.10 -51 04 00.0 βPic b = * bet Pic b
05 47 17.09 -51 03 59.4 βPic c = * bet Pic c
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 55 122 Predicted positions of βPic b
table3.dat 57 122 Predicted positions of βPic c
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
J/A+A/542/A18 : βPic Harps radial velocity data (Lagrange+, 2012)
J/ApJ/745/174 : Evolutionary models young gas-giant planets (Spiegel+, 2012)
J/ApJ/758/56 : Young M dwarfs within 25pc. II. Kinematics (Shkolnik+, 2012)
J/MNRAS/454/593 : Young moving groups in solar neighbourhood (Bell+, 2015)
J/A+A/607/A25 : beta Pic HARPS spectrum (Vidal-Madjar+, 2017)
J/AJ/156/18 : APOGEE DR14:Binary comps evolved stars (Price-Whelan+, 2018)
J/A+A/625/L13 : TESS light curve of beta Pictoris (Zieba+, 2019)
J/A+A/627/A28 : beta Pic BRITE, bRing, SMEI light curves (Zwintz+, 2019)
J/A+A/633/A110 : K band spectrum of beta Pictoris b (GRAVITY+, 2020)
J/A+A/648/A15 : beta Pictoris photometry (Kenworthy+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 d MJD [59213/61028] Modified Julian Date, JD-2400000.5
9- 14 F6.2 mas dRA [211/305] Offset in Right Ascension
16- 21 F6.2 mas dDE [351/488] Offset in Declination
23- 27 F5.3 mas e_dRA [0.33/6.67] Uncertainty in dRA
29- 34 F6.3 mas e_dDE [0.54/10.9] Uncertainty in dDE
36- 41 F6.4 --- rhoad [0.95/1] Correlation coefficient between RA and DE
43- 48 F6.2 mas Sep [410/576] Separation
50- 55 F6.3 mas e_Sep [0.13/12.8] Uncertainty in Sep
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 d MJD [59213/61028] Modified Julian Date, JD-2400000.5
9- 14 F6.2 mas dRA [-78.2/56.8] Offset in Right Ascension
16- 22 F7.2 mas dDE [-129/94.9] Offset in Declination
24- 29 F6.3 mas e_dRA [0.93/20.2] Uncertainty in dRA
31- 36 F6.3 mas e_dDE [1.18/31.6] Uncertainty in dDE
38- 43 F6.4 --- rhoad [0.34/1] Correlation coefficient between RA and DE
45- 50 F6.2 mas Sep [1.59/151] Separation
52- 57 F6.3 mas e_Sep [1.28/37.4] Uncertainty in Sep
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 28-Jun-2021