J/A+A/665/A154 HD23472 radial velocity observations (Barros+, 2022)
HD 23472: a multi-planetary system with three super-Earths and two potential
super-Mercuries.
Barros S., Demangeon O.D.S., Alibert Y., Leleu A., Adibekyan V., Lovis C.,
Bossini D., Sousa S.G., Hara N., Bouchy F., Lavie B., Rodrigues J.,
Gomes da Silva J., Lillo-Box J., Pepe F.A., Tabernero H.M.,
Zapatero Osorio M.R., Sozzetti A., Suarez Mascareno A., Micela G.,
Allende Prieto C., Cristiani S., Damasso M., Di Marcantonio P.,
Ehrenreich D., Faria J., Figueira P., Gonzalez Hernandez J.I., Jenkins J.,
Lo Curto G., Martins C.J.A.P., Micela G., Nunes N.J., Palle E., Santos N.C.,
Rebolo R., Seager S., Twicken J.D., Udry S., Vanderspek R., Winn J.N.
<Astron. Astrophys. 665, A154 (2022)>
=2022A&A...665A.154B 2022A&A...665A.154B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Spectroscopy ; Optical
Keywords: planets and satellites: detection -
planets and satellites: composition -
planets and satellites: terrestrial planets -
stars: individual: HD 23472 - techniques: radial velocities -
techniques: photometric
Abstract:
Comparing the properties of planets orbiting the same host star, and
thus formed from the same accretion disc, helps in constraining
theories of exoplanet formation and evolution. As a result, the
scientific interest in multi-planetary systems is growing with the
increasing number of detections of planetary companions.
We report the characterisation of a multi-planetary system composed of
five exoplanets orbiting the K-dwarf HD 23472 (TOI-174).
In addition to the two super-Earths that were previously confirmed, we
confirm and characterise three Earth-size planets in the system using
ESPRESSO radial velocity observations. The planets of this compact
system have periods of Pd∼3.98, Pe∼7.90, Pf∼12.16, Pb∼17.67 and
Pc∼29.80-days and radii of Rd∼0.75, Re∼0.82, Rf∼1.13, Rb∼2.01, and,
Rc∼1.85R⊕. Because of its small size, its proximity to planet
d transit, and close resonance with planet d, planet e was only
recently found.
The planetary masses were estimated to be Md=0.54±0.22,
Me=0.76±0.30, Mf=0.64±0.46, Mb=8.42±0.84, and
Mc=3.37±0.92M⊕. These planets are among the lightest
planets, with masses measured using the radial velocity method,
demonstrating the very high precision of the ESPRESSO spectrograph. We
estimated the composition of the system five planets and found that
their gas and water mass fractions increase with stellar distance,
suggesting that the system was shaped by irradiation. The high density
of the two inner planets rhod=7.5±3.9 and rhoe=7.5±3.9g/cm3
indicates that they are likely to be super-Mercuries. This is
supported by the modelling of the internal structures of the planets,
which also suggests that the three outermost planets have significant
water or gas content.
If the existence of two super-Mercuries in the system is confirmed,
this system will be the only one known to feature two super-Mercuries,
making it an excellent testing bed for theories of super-Mercuries
formation. Furthermore, the system is close to a Laplace resonance,
and further monitoring could shed light on how it was formed. Its
uniqueness and location in the continuous viewing zone of the James
Webb space telescope will make it a cornerstone of future in-depth
characterisations.
Description:
We present Radial Velocity observations of HD 23472 obtained with
ESPRESSO. We also give the stellar activity indicators: FWHM, Bisector
span, contrast, S-index, width of the Hα line and width of the
Calcium line
Objects:
------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------
03 41 50.40 -62 46 01.5 HD 23472 = TOI-174
------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
expre_rv.dat 183 104 Radial velocity observations
--------------------------------------------------------------------------------
See also:
J/A+A/622/L7 : GJ143 and HD23472 radial velocity curves (Trifonov+, 2019)
Byte-by-byte Description of file: expre_rv.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.12 d Time Time of the measurement, UTC (BJD-2400000)
20- 31 F12.6 m/s RV Radial velocity
33- 40 F8.6 m/s e_RV Uncertainty on the radial velocity (1 sigma)
42- 52 F11.6 m/s FWHM Full width at half maximum of the
cross-correlation function
54- 61 F8.6 m/s e_FWHM Uncertainty on the full width at half maximum
(1 sigma)
63- 71 F9.6 m/s BIS Bisector span of the cross-correlation function
73- 80 F8.6 m/s e_BIS Uncertainty on the bisector span (1 sigma)
82- 90 F9.6 --- Contrast Contrast of the cross-correlation function
92- 99 F8.6 --- e_Contrast Uncertainty on the contrast (1 sigma)
101-109 F9.6 --- Sindex Mont-Wilson S index
111-118 F8.6 --- e_Sindex Uncertainty on the S index (1 sigma)
120-127 F8.6 --- Halpha Depth of the Hα line
129-136 F8.6 --- e_Halpha Uncertainty on the depth of the Hα line
(1 sigma)
138-145 F8.6 --- NaD Depth of the sodium doublet lines
147-154 F8.6 --- e_NaD Uncertainty on the depth of the sodium doublet
lines (1 sigma)
156-164 F9.6 --- Ca Depth of the Calcium lines
166-173 F8.6 --- e_Ca Uncertainty on the depth of the Calcium lines
(1 sigma)
175-183 F9.6 m/s BERV Barycentric Earth Radial Velocity
--------------------------------------------------------------------------------
Acknowledgements:
Susana Barros, susana.barros (at) astro.up.pt
(End) Patricia Vannier [CDS] 09-Aug-2022