Alpha Centauri A Archives - Astrobiology

These panels represent the Lomb-Scargle power for different activity cycle power frequencies found in the dataset of Alpha Centauri A and B. The highest power for a period > 5 years is marked by the blue dashed line which amounts to 22.2 years for Alpha Centauri A and 8.2 years for Alpha Centauri B. Bottom: These panels represent the sinusoidal fit to the MgII index data for Alpha Centauri A and B. The solar MgII index is overlaid in the figure for reference. The solar MgII index is obtained from the LISIRD website (Leise et al. 2019). -- astro-ph.SR

Alpha Centauri, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Space Weather & Heliophysics, Status Report, Stellar Cartography

Near UV Stellar Activity and Brightness Fluctuations of the Alpha Centauri AB Star System from Weeks to Decades — Inputs for Reflected Light Spectroscopy with HWO

by Keith CowingMay 27, 2026May 27, 2026

We present the most comprehensive near-ultraviolet (NUV: 2550-3255 Angstrom) activity record to date for the Alpha Centauri AB system, combining archival IUE and HST observations spanning nearly five decades with […]

Alpha Centauri, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Imaging & Spectroscopy, Status Report, Stellar Cartography

Seeking The Worlds Of Avatar: Prospects for Detecting Moons Orbiting a Giant Planet in Alpha Centauri A’s Habitable Zone

by Keith CowingSeptember 22, 2025September 22, 2025

Nearby giant exoplanets offer an opportunity to search for moons (exomoons) orbiting them. Here, we present a simulation framework for investigating the possibilities of detecting exomoons via their astrometric signal […]

This image shows the Alpha Centauri star system from several different ground- and space-based observatories: the Digitized Sky Survey (DSS), the NASA/ESA Hubble Space Telescope, and the NASA/ESA/CSA James Webb Space Telescope. Alpha Centauri A is the third brightest star in the night sky, and the closest Sun-like star to Earth. -- ESA

Alpha Centauri, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Imaging & Spectroscopy, Press Release

Webb Finds New Evidence For A Large Planet Orbiting in The Habitable Zone Of Alpha Centauri A

by Keith CowingAugust 7, 2025August 7, 2025

Astronomers using the NASA/ESA/CSA James Webb Space Telescope have found strong evidence of a giant planet orbiting a star in the stellar system closest to our own Sun. At just […]

JWST’s view of the α Cen AB system. Shown above is a background-subtracted Stage 2b F1550C image of the α Cen AB system from August 2024. The image is oriented North up and East left. The white stars denote the approximate positions of α Cen B, saturated near the top of the image, and α Cen A in the lower part of the image hidden behind the F1550C mask. The right colorbar (logarithmically scaled) is associated with this image. At the edge of the detector, to the West of α Cen A, is a known background source KS5 (Kervella et al. 2016). To the East of α Cen A is known background source KS2 (Kervella et al. 2016), shown as an inset, as it is only detected after performing PSF subtraction (no colorbar shown for the inset, scaled linearly between −5 and 50 MJy/sr). An ≈2. ′′75 radius region around α Cen A is shaded and mapped to three PSF-subtracted images, one for each observation epoch. Candidate S1 is seen only in August 2024. The bottom colorbar (linearly scaled) is associated with the three PSF-subtracted images. For reference, 1 MJy/sr ≈ 4.6 × 10−6 Jy/AiryCore, where AiryCore is defined as the area of a circular aperture of diameter 1 FWHM (≈ 0. ′′5). -- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Imaging & Spectroscopy, Status Report

Worlds Next Door: A Candidate Giant Planet Imaged in the Habitable Zone of α Cen A. I. Observations, Orbital and Physical Properties, and Exozodi Upper Limits

by Keith CowingAugust 7, 2025August 7, 2025

We report on coronagraphic observations of the nearest solar-type star, α Cen A, using the MIRI instrument on the James Webb Space Telescope.

Joint PCA-KLIP subtraction of distinct subsets of the α Cen AB science integrations from the August 2024 observations. -- astro-ph.SR

Alpha Centauri, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Imaging & Spectroscopy, Press Release

Worlds Next Door: A Candidate Giant Planet Imaged in the Habitable Zone of α Cen A. II. Binary II. Binary Star Modeling, Planet and Exozodi Search, and Sensitivity Analysis

by Keith CowingAugust 7, 2025September 18, 2025

JWST observed our closest solar twin, α Cen A, with the MIRI coronagraph in F1550C (15.5 μm) at three distinct epochs between August 2024 and April 2025.

F1550C image of α Cen AB. α Cen B is saturated near the top and α Cen A is behind the F1550C mask near the center. Two known background stars are labeled (KS2 inset, detected after PSF subtraction; and KS5). The (right) colorbar (for the Stage 2b image) is logarithmically scaled in MJy/sr. A ≈ 35 radius region around α Cen A is expanded. (a) The original α Cen AB PSF-subtracted image. Dashed lines indicate the FQPM boundaries. A likely artifact is boxed. (b) An identical reduction after injecting STPSF planet models (circled). (c) An identical reduction after injecting an exozodiacal disk model (boxed). The (bottom) colorbar (for the reduced images and KS2) is linearly scaled in MJy/sr. -- Research Notes of the AAS

Alpha Centauri, Astronomy & Telescopes, Exploration Gear & Tech, Imaging & Spectroscopy, Press Release

A Preliminary Search For Planets and Exozodiacal Emission Around Alpha Centauri A with JWST/MIRI

by Keith CowingMay 26, 2025May 26, 2025

We present F1550C (15.5 μm) coronagraphic imaging observations of the nearest solar-type star α Cen A using the James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI).

This map shows the geographic distribution of the mobile towers of planet Earth, represented by red dots. The map contains more than 30 million individual data points, most of which overlap at this resolution. -- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Barnard's Star, Biosignatures & Paleobiology, Intelligence & Language, SETI & Technosignatures, Status Report

Simulation Of The Earth’s Radio Leakage From Mobile Towers As Seen From Selected Nearby Stellar Systems

by Keith CowingMay 26, 2025May 26, 2025

Mobile communication towers represent a relatively new but growing contributor to the total radio leakage associated with planet Earth.