System // Entry 002 — ⚡ JWST Urgent

Alpha Centauri A

HD 128620 · α Cen A · Nearest stellar neighbor · 1.34 pc · G2V

Section 01

General Information

Spectral type
G2V
Teff
~5790 K
log g
~4.31
[Fe/H]
+0.20 dex
Mass
~1.10 M☉
Distance
1.34 pc
Status
⚡ JWST Aug 26
The Alpha Centauri system — Alpha Cen A, B, and Proxima Centauri
Credit: ESA/Hubble — Alpha Centauri A and B binary system
⚡ URGENT — JWST Follow-Up August 2026

A candidate Saturn-mass planet around Alpha Cen A was detected by the JWST MIRI coronagraph. A follow-up observation is scheduled for August 2026 to confirm the detection. The Codex is measuring Alpha Cen A's stellar abundances in parallel to provide host-star chemistry context for any confirmed planet. 75 HARPS S1D files complete (SNR>1000); HST/MAST UV data downloading.

Science Context

Alpha Cen A is almost a solar twin — G2V, [Fe/H] ≈ +0.20, age ~5 Gyr. Its proximity (1.34 pc) gives HARPS the highest possible SNR of any FGK target, making it an ideal calibration check against the Sun. The JWST MIRI planet candidate (2-year orbit, ~Saturn mass) adds a compelling reason to complete the abundance analysis urgently.

Stellar Parameters

ParameterSymbolValueSource
Effective temperatureTeff~5790 KLiterature consensus
Surface gravitylog g~4.31Literature consensus
Metallicity[Fe/H]~+0.20 dexLiterature consensus
MassM★~1.10 M☉Literature consensus
Spectral type—G2VNearly solar twin
Distanced1.34 pc (4.37 ly)Hipparcos / Gaia

Known Planets

PlanetMassTypeSemi-major axisHab zone
Candidate (MIRI)~Saturn-massGas giant candidate~2 AUTBD — unconfirmed

Section 02

NASA Interactive Visualization

// SYSTEM SCAN — NASA EXOPLANET ARCHIVE //
Interactive: NASA Eyes on Exoplanets / JPL Open NASA page ↗
// INTERACTIVE SKY VIEW //

Section 04

Our Findings

Spectral analysis of Alpha Centauri A is in progress (Entry 002). HARPS dataset: 75 S1D files, SNR > 1000, complete. HST/MAST UV data (111 observations): downloading. Elemental abundances for 27 elements will publish here upon pipeline completion. Priority elevated due to JWST August 2026 re-observation deadline.

Section 05

References & Credits

Key Literature

Pourbaix et al. (2016) — Alpha Cen binary orbit

Thévenin et al. (2002) — stellar parameters

JWST MIRI coronagraph detection (in preparation)

de Mooij et al. (2023) — candidate planet detection

Data Sources

NASA/IPAC Exoplanet Archive

SIMBAD / CDS — stellar parameters

Hipparcos / Gaia — parallax & distance

Image Credits

Credit: ESA/Hubble — Alpha Centauri A and B binary system

Interactive sky: CDS Aladin Lite v3 / DSS2

NASA Eyes: NASA/JPL-Caltech

Pipeline

HARPS S1D — ESO Science Archive

Analysis: The Exoplanet Codex

github.com/damienabraxas/exoplanetcodex

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