J/A+A/613/A25 Radial velocity for Ross 128 (Bonfils+, 2018)
A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs.
Bonfils X., Astudillo-Defru N., Diaz R., Almenara J.-M., Forveille T.,
Bouchy F., Delfosse X., Lovis C., Mayor M., Murgas F., Pepe F.,
Santos N. C., Segransan D., Udry S., Wunsche A.
<Astron. Astrophys. 613, A25 (2018)>
=2018A&A...613A..25B 2018A&A...613A..25B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Radial velocities
Keywords: planetary systems - stars: late-type - techniques: radial velocities
Abstract:
After that a new technique combining high-contrast imaging and
high-dispersion spectroscopy successfully detected the atmosphere of a
giant planet, it soon became contemplated as one of the most promising
avenues to study the atmosphere of Earth-size worlds. With the
forthcoming ELTs, it shall gain the angular resolution and sensitivity
to even detect O2 in the atmosphere of planets orbiting red dwarfs.
This is a strong motivation to make the census of planets around cool
stars which habitable zones can be resolved by ELTs, i.e. for M dwarfs
within ∼5-parsecs. In that context, our HARPS survey is already a
major contributor to that sample of nearby planets. Here we report on
our radial-velocity observations of Ross 128 (Proxima Virginis, GJ447,
HIP 57548), a M4 dwarf just 3.4-parsec away from our Sun. We detect it
is host of an exo-Earth with a projected mass m*sini=1.35M☉ and
an orbital period of 9.9-days. Ross 128 b receives ∼1.38 as much flux
as Earth from the Sun and has an equilibrium temperature between 269K
(resp. 213K) for an Earth-like (resp. Venus-like) albedo. According to
recent studies, it is located at the inner edge of the so called
habitable zone. An 80-day long light curve performed by K2 during
campaign C01 excludes Ross 128 b is a transiting planet. Together with
ASAS photometry and other activity indices, it argues for a long
rotational period and a weak activity which, in the context of
habitability, gives a high merit to the detection. Today, Ross 128 b
is the second closest known exo-Earth after Proxima Centauri b (1.3
parsec) and the closest known temperate planet around a quiet star. At
maximum elongation, the planet-star angular separation of 15
milli-arcsec will be resolved by the ELT (>3λ/D) in all optical
bands of O2.
Description:
The tables contain radial-velocity time series of Ross 128.
Radial velocities were obtained with he HARPS spectrograph on the 3.6m
telescope at La Silla, Chile.
Objects:
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RA (2000) DE Designation(s)
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11 47 44.4 +00 48 16 Ross 128 = V* FI Vir
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 34 159 HARPS measured RV for Ross 128
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Barycentric Julian date
16- 24 F9.5 km/s RV Barycentric radial velocity
26- 32 F7.5 km/s e_RV Radial-velocity uncertainty
34 I1 --- Inst [1/2] Instrument upgrade flag
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Acknowledgements:
Xavier Bonfils, xavier.bonfils(at)univ-grenoble-alpes.fr
(End) Xavier Bonfils [IPAG], Patricia Vannier [CDS] 30-Oct-2017