J/A+A/595/A77 GJ676A radial velocity curve (Sahlmann+, 2016)
The mass of planet GJ676A b from ground-based astrometry: A planetary system
with two mature gas giants suitable for direct imaging.
Sahlmann J., Lazorenko P.F., Segransan D., Astudillo-Defru N., Bonfils X.,
Delfosse X., Forveille T., Hagelberg J., Lo Curto G., Pepe F., Queloz D.,
Udry S., Zimmerman N.T.
<Astron. Astrophys. 595, A77 (2016)>
=2016A&A...595A..77S 2016A&A...595A..77S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Radial velocities
Keywords: stars: low-mass - planetary systems - astrometry -
stars: individual: GJ676A
Abstract:
The star GJ676A is an M0 dwarf hosting both gas-giant and
super-Earth-type planets that were discovered with radial-velocity
measurements. Using FORS2/VLT, we obtained position measurements of
the star in the plane of the sky that tightly constrain its
astrometric reflex motion caused by the super-Jupiter planet 'b' in a
1052-day orbit. This allows us to determine the mass of this planet to
be Mb= 6.7+1.8-1.5MJ, which is ∼40% higher than the minimum
mass inferred from the radial-velocity orbit. Using new HARPS
radial-velocity measurements, we improve upon the orbital parameters
of the inner low-mass planets 'd' and 'e' and we determine the orbital
period of the outer giant planet 'c' to be Pc=7340-days under the
assumption of a circular orbit. The preliminary minimum mass of planet
'c' is Mcsini=6.8MJ with an upper limit of ∼39MJ that we set
using NACO/VLT high-contrast imaging. We also determine precise
parallaxes and relative proper motions for both GJ676A and its wide M3
companion GJ676B. Although the system is probably quite mature, the
masses and projected separations (∼0.1-0.4") of planets 'b' and 'c'
make them promising targets for direct imaging with future instruments
in space and on extremely large telescopes. In particular, we estimate
that GJ676A b and GJ676A ,c are promising targets for directly
detecting their reflected light with the WFIRST space mission. Our
study demonstrates the synergy of radial-velocity and astrometric
surveys that is necessary to identify the best targets for such a
mission.
Description:
HARPS radial velocities of GJ676A and their uncertainties used in this
publication. The values in file gj676a-1.dat were obtained with the
method described in Astudillo-Defru+15. The data underlying file
gj676a-2.dat was taken after the HARPS upgrade and the velocities were
obtained with the ESO standard pipeline.
Objects:
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RA (2000) DE Designation(s)
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17 30 11.20 -51 38 13.1 GJ676A = HIP 85647
17 30 16.28 -51 38 22.3 GJ676B = NLTT 44860
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gj676a-1.dat 34 127 HARPS RV of GJ676A taken before upgrade
gj676a-2.dat 34 2 HARPS RV of GJ676A taken after upgrade
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Byte-by-byte Description of file: gj676a-1.dat gj676a-2.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d JD Julian Date of the observation
16- 25 F10.6 km/s RV Radial velocity
27- 34 F8.6 km/s e_RV Uncertainty in radial velocity
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Acknowledgements:
Johannes Sahlmann, Johannes.Sahlmann(at)esa.int
(End) Patricia Vannier [CDS] 20-Aug-2016