Access to Astronomical Catalogues

← Click to display the menu
J/A+A/615/A69    K2-3 system characterized with HARPS-N & HARPS (Damasso+, 2018)

Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS. Damasso M., Bonomo A.S., Astudillo-Defru N., Bonfils X., Malavolta L., Sozzetti A., Lopez E., Zeng L., Haywood R.D., Irwin J.M., Mortier A., Vanderburg A., Maldonado J., Lanza A.F., Affer L., Almenara J.-M., Benatti S., Biazzo K., Bignamini A., Borsa F., Bouchy F., Buchhave L.A., Cameron A.C., Carleo I., Charbonneau D., Claudi R., Cosentino R., Covino E., Delfosse X., Desidera S., Di Fabrizio L., Dressing C., Esposito M., Fares R., Figueira P., Fiorenzano A.F.M., Forveille T., Giacobbe P., Gonzalez-Alvarez E., Gratton R., Harutyunyan A., Asher Johnson J., Latham D.W., Leto G., Lopez-Morales M., Lovis C., Maggio A., Mancini L., Masiero S., Mayor M., Micela G., Molinari E., Motalebi F., Murgas F., Nascimbeni V., Pagano I., Pepe F., Phillips D.F., Piotto G., Poretti E., Rainer M., Rice K., Santos N.C., Sasselov D., Scandariato G., Segransan D., Smareglia R., Udry S., Watson C., Wuensche A. <Astron. Astrophys. 615, A69 (2018)> =2018A&A...615A..69D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Exoplanets ; Radial velocities Keywords: stars: individual: K2-3 - planets and satellites: detection - planets and satellites: composition - techniques: radial velocities - stars: individual: EPIC 201367065 - stars: individual: 2MASS 11292037-0127173 Abstract: M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb=6.6±1.1M) and planet c (Mc=3.1+1.3-1.2M). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md=2.7+1.2-0.8M. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (<1percent) or massive water layers, with a water content >50 percent of their total mass, on top of rocky cores. Placing further constraints on the bulk densities of K2-3 c and d is difficult; in particular, we would not have been able to detect the Doppler signal of K2-3 d even by adopting a semester of intense, high-cadence radial velocity observations with HARPS-N and HARPS. Description: Radial velocities of K2-3, collected with HARPS-N and HARPS and extracted with two algorithms (TERRA and the alternative pipeline described in Astudillo-Defru et al. 2015A&A...575A.119A, 2017A&A...602A..88A), are presented . Also included is the time series of the spectroscopic activity indicator based on the H-alpha line, as extracted from the HARPS-N and HARPS spectra. Objects: ----------------------------------------------------------- RA (2000) DE Designation(s) ----------------------------------------------------------- 11 29 20.39 -01 27 17.2 K2-3 = 2MASS J11292037-0127173 ----------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 26 197 Radial velocities of K2-3 extracted from HARPS-N spectra using the TERRA algorithm tablea2.dat 26 132 Radial velocities of K2-3 extracted from HARPS spectra using the TERRA algorithm tablea3.dat 28 197 Radial velocities of K2-3 extracted from HARPS-N spectra using the alternative pipeline tablea4.dat 28 132 Radial velocities of K2-3 extracted from HARPS spectra using the alternative pipeline tablea5.dat 30 329 Time series of the activity indicator based on the H-alpha line extracted from HARPS-N and HARPS spectra
Byte-by-byte Description of file: tablea1.dat tablea2.dat
Bytes Format Units Label Explanations
1- 12 F12.6 d Time Epoch of observation (BJD-2400000) 15- 20 F6.2 m/s RV Radial velocity (1) 23- 26 F4.2 m/s e_RV Radial velocity error
Note (1): Radial velocities are relative to a high S/N template For table5.dat, Radial velocities starting from epoch BJD 2457199 were collected after the upgrade of the instrument. An offset between the pre- and post-upgrade datasets should be included in fitting model.
Byte-by-byte Description of file: tablea3.dat tablea4.dat
Bytes Format Units Label Explanations
1- 12 F12.6 d Time Epoch of observation (BJD-2400000) 15- 22 F8.2 m/s RV Radial velocity (1) 25- 28 F4.2 m/s e_RV Radial velocity error
Note (1): Radial velocities include the systemic velocity. For table7.dat, Radial velocities starting from epoch BJD 2457199 were collected after the upgrade of the instrument. An offset between the pre- and post-upgrade datasets should be included in fitting model.
Byte-by-byte Description of file: tablea5.dat
Bytes Format Units Label Explanations
1- 12 F12.6 d Time Epoch of observation (BJD-2400000) 15- 21 F7.5 m/s ActInd H-alpha activity indicator 24- 30 F7.5 m/s e_ActInd H-alpha activity indicator error
Acknowledgements: Mario Damasso, mario.damasso(at)inaf.it
(End) Mario Damasso [INAF-OATo, Italy], Patricia Vannier [CDS] 11-May-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© Université de Strasbourg/CNRS

    • Contact