Six fixed noise models give conditional 95% CARMENES amplitude bounds of 0.720–1.444 m/s for Barnard's star at eccentricity 0.306 on a finite 58.59–58.88-day orbit grid
This study tests the nominal amplitude of the 58.738-day HARPS candidate GJ699_2 with free phase and orientation. We use public DR1 velocities of Barnard's star: 473 spectra in 464 nightly bins. We test 57,600 finite orbit shapes, all orientations, six fixed Gaussian noise covariances, and two linear nuisance models. At each shape, an exact two-coefficient 95 percent ellipse gives a conservative amplitude upper bound. At the source eccentricity 0.306401, the bounds range from 0.7203 to 1.4442 m/s. The nominal HARPS amplitude is 1.2268 m/s. Five noise models give bounds below it with both nuisance models; the 4 m/s correlated-noise stress case does not. With the full eccentricity grid up to 0.8, all settings give larger bounds, from 1.5575 to 2.6635 m/s. Explicit coefficient ellipses test allowed nominal-amplitude examples. Independent solvers, regression checks, Gaussian simulations, and a finer grid check the calculation. A separate calculation reproduces all eight scientific CSV tables. Correlated-noise settings give low nuisance-only residual costs, so they are sensitivity tests, not measured noise models. Coverage requires the stated covariance and nuisance mean and a true shape on the finite grid. The study is retrospective. It does not give continuous-orbit coverage, a joint HARPS uncertainty test, a planet detection, or a physical cause. The package preserves code, input hashes, public data, tables, and figures.
Barnard's star · CARMENES · radial velocity · exoplanet candidate · confidence ellipse · correlated noise · eccentricity · reproducible astronomy
References
9- usesA blind Keplerian search of 743 HARPS-RVBank v2 stars with 30 or more nights recovers 248 of 465 known planets and finds 57 signals (FAP < 0.1 %) with no known match that pass activity tests sci:sha256:17e2629023ac1bcbb507eb643afc93a73a34d8a9d1ba2357cc22bd7bc4f108cb
Supplies the HARPS candidate orbit and the other long-period nuisance signal.
- usesFour of five fixed HARPS candidate curves disagree with CARMENES DR1 under a 90-day block error model sci:sha256:e8c306d84e6b5d0e3fc719a5eb2c079a80ff6c319d10463c832d06dcd0ad3f9d
Supplies verified public DR1 inputs, original archive rows, data provenance, selection rules, and the prior fixed-phase and descriptive phase-scan results.
- usesCARMENES DR1 signed amplitudes are below four HARPS candidate estimates with fixed periods, orbit shapes, and phases sci:sha256:589d12c5ff580d78cb1224bb4c92ee22180c79382f4e3738f685b43c5027e199
Provides the prior fixed-shape and fixed-phase amplitude test that this work extends.
- usesdoi:10.1051/0004-6361/202244879
CARMENES DR1 measurements and archive context.
- doi:10.1051/0004-6361/202348263
HARPS-RVBank v2 underlies the cited source candidate survey.
- doi:10.1051/0004-6361/201936686
Original HARPS-RVBank methods and data context.
- usesdoi:10.1051/0004-6361/202451311
Activity context for the fixed 142-day rotation period and 71-day harmonic; covariance choices remain sensitivity assumptions.
- usesdoi:10.3847/2041-8213/adb8d5
Supplies the four short periods used as free sine and cosine nuisance pairs.
- 54 GJ 581 CARMENES velocities give a 95% limit of 1.26 m/s for a 66.7-day sinusoid with fixed planet periods and independent Gaussian noise sci:sha256:4dae6f6c26111939f7b75f46605c25a2c00e71261fdc4d9ffa46ea0d7b3350ac
Prior phase-free coefficient-ellipse bounds for a circular GJ 581 signal with an estimated common noise scale. The present analysis uses a different target, fixed absolute covariance, and eccentric orbit grids.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- supportsIndependent RVs reject 13 of 25 testable HARPS-RVBank v2 candidates (3 if HARPS errors double) and agree with a 19.7-day HD 111232 signal, with linear-trend nuisance models
Barnard's star 58.7 d with CARMENES: 95% bounds of 0.720-1.444 m/s for a free phase. Our CARMENES fit gives K_free = 0.21 +/- 0.15 m/s and all data give 0.11 +/- 0.11 m/s. Both works find less amplitude than the HARPS prediction (1.23 m/s).
- A fixed Gaussian HARPS model gives a nominal 95% amplitude bound below 0.90 m/s at 197.8 days for HD 40307 orbits with eccentricity up to 0.60
This prior study used two-coefficient Gaussian ellipses and their union for finite eccentric-orbit grids. That confidence construction is prior work. Our HD 40307 calculation adds an analytic allowance between eccentricity and phase samples at one fixed period, with an audited support-function bracket for sampled ellipses. We do not reuse this prior package code or data.
- 2023 Barnard's Star date means give a positive 4.1244-day band term at the 2021–2022 phase under independent Gaussian errors
This earlier CARMENES study gives conservative coefficient-ellipse amplitude bounds under fixed covariance models for a different Barnard candidate. Our observations and tested periods differ.