Free Access
Table A.2
K2-18 model parameters from the HARPS+CARMENES joint RV analysis.
| Parameter | Point estimate |
|---|---|
| Stellar Parameters | |
| 2MASS Photometry | J = 9.763 ± 0.028, H = 9.135 ± 0.026, Ks = 8.899 ± 0.019 |
| Stellar mass, Ms [M⊙] | 0.495 ± 0.004 |
| Stellar radius, Rs [R⊙] | 0.469 ± 0.010 |
| Effective temperature, Teff [K] | 3503 ± 60 |
| Stellar parallax, p [mas] | 26.299 ± 0.055 |
| Distance, d [pc] | 38.025 ± 0.079 |
| HARPS systemic velocity, γ0,HARPS [m s−1] | 652.51 ± 1.0 |
| CARMENES systemic velocity, γ0,CARMENES [m s−1] | − 2.87 ± 0.9 |
| GP hyperparameters | |
| HARPS covariance amplitude, aHARPS [m s−1] |  |
| CARMENES covariance amplitude, aCARMENES [m s−1] |  |
| Exponential timescale, λ [days] | 448.8 ± 67.3 |
| Coherence, Γ |  |
| Periodic timescale, PGP [days] |  |
| HARPS additive jitter, sHARPS [m s−1] | 0.48 ± 0.42 |
| CARMENES additive jitter, sCARMENES [m s−1] | 0.58 ± 0.53 |
| K2-18c | |
| Period, Pc [days] | 8.997 ± 0.007 |
| Time of inferior conjunction, T0,c [BJD-2 450 000] | 7263.69 ± 0.44 |
| Radial velocity semi-amplitude, Kc [m s−1] | 2.76 ± 0.41 |
 |
 |
 |
 |
| Semi-major axis, ac [AU] | 0.0670 ± 0.0002 |
| Minimum planet mass, mp,c sinic [M⊕] | 5.62 ± 0.84 |
| Equilibrium temperature, Teq,c [K] | |
| Bond albedo of 0.3 | 409 ± 8 |
| K2-18b | |
| Period, Pb [days] | 32.93962 ± 1.0 × 10−4 |
| Time of inferior conjunction, T0,b [BJD-2 450 000] | 7264.39142 ± 6.4 × 10−4 |
| Radial velocity semi-amplitude, Kb [m s−1] | 2.75 ± 0.43 |
 |
 |
 |
 |
| Semi-major axis, ab [AU] | 0.1591 ± 0.0004 |
| Planet radius, rp,b [R⊕]a | 2.711 ± 0.065 |
| Planet mass, mp,b [M⊕]b | 8.63 ± 1.35 |
| Planet density, ρp,b [g cm-3] | 2.4 ± 0.4 |
| Surface gravity, g [m s-2] | 11.5 ± 1.9 |
| Escape velocity, vesc,b [km s-1] | 19.9 ± 1.6 |
| Equilibrium temperature, Teq,b [K] | |
| Bond albedo of 0.3 | 265 ± 5 |
Notes. (a) Based on the measured rp,b ∕Rs of K2-18b from Benneke et al. (2017); rp,b∕Rs = 0.05295 ± 0.00060. (b) Assuming the measured orbital inclination of K2-18b from Benneke et al. (2017); 
degrees.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.