Alpha Centauri Archives

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.

Top: an example of a chop-subtraction image pair from VLT/NEAR. Image B, following 0.05 sec after A, is subtracted to remove the detector bias, thermal background, AGPM glow, and excess low frequency noise (ELFN). Bottom: an example model of a chop-subtraction persistence residual (CSPR) of α Centauri AB. This model was generated with an offset of ∼2% of a pixel, or ∼1 mas, of the star’s position behind the coronagraph following each chop. The effects of the coronagraph, persistence non-linearity and temporal decay, and post-processing are not included in the model. The CSPR is too faint to be seen in the frames above, but is easily seen in longer integrations (see Fig. 2). -- astro-ph.IM

Alpha Centauri, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Imaging Low-mass Planets Within The Habitable Zones Of Nearby Stars With Ground-based Mid-infrared Imaging

by Keith CowingMay 26, 2025May 26, 2025

Giant exoplanets on 10-100 au orbits have been directly imaged around young stars. The peak of the thermal emission from these warm young planets is in the near-infrared (~1-5 microns), […]

α Cen’s orbit about the Galactic Centre viewed on the xy and yz planes (top row), as well as the orbits of the ejecta from α Cen viewed in a comoving frame (bottom row). Our Sun (Sol) is marked by a black hexagon and its orbital path indicated by a grey solid line (top row only). α Cen’s location and path are shown by a yellow star and blue solid line (top row only). In the bottom row, the comoving frame follows α Cen around its orbit while maintaining its orientation with the y-axis pointing towards the Galactic Centre (blue arrow) and α Cen’s velocity pointing in the -x direction (black arrow). This still frame is taken at t ≈ 3, 000 yr (that is, +3,000 years from the current epoch) after ∼ 100 Myr of integration. The colours of the ejecta represent the 3rd dimension of position, except that any particle that will at any point come within 100, 000 au of Sol are plotted in red. The full animation is available in the HTML version of this publication which shows the time evolution from t ≈ −100 Myr to t ≈ 10 Myr. The duration of the animation is 11 s. https://youtu.be/YABoYgNKr-I -- astro-ph.EP

Alpha Centauri, Comets and Asteroids, Interstellar, Meteorites & Asteroids, Panspermia, Press Release

A Case Study of Interstellar Material Delivery: Alpha Centauri

by Keith CowingFebruary 6, 2025February 6, 2025

Interstellar material has been discovered in our Solar System, yet its origins and details of its transport are unknown. Here we present α Centauri as a case study of the […]

ESPRESSO RV measurements (right) and GLS periodograms (left) of GJ 699 after subtracting the median of each dataset before (E18) and after (E19) the intervention in June 2019. Also shown are RV measurements from the ESPRESSO Data Reduction Software (DRS; top), from the S-BART template matching (TM) code (middle), and from the line-by-line LBL code (bottom).-- astro-ph.EP

Alpha Centauri, Astronomy & Telescopes, Barnard's Star, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

A Sub-Earth-mass Planet Orbiting Barnard’s Star

by Keith CowingOctober 4, 2024

Barnard’s star is a primary target within the ESPRESSO guaranteed time observations (GTO) as it is the second closest neighbour to our Sun after the α Centauri stellar system.

Artist’s rendition of variety of exoplanets featured in the new NASA TESS-Keck Survey Mass Catalog, the largest, single, homogenous analysis of TESS planets released by any survey thus far. Credit: W. M. Keck Observatory/Adam Makarenko

Alpha Centauri, Astrogeology, Beta Pictoris, Ceres, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Jupiter, Lava / magma ocean / Volcanic Worlds, Mapping, Geodesy, Cartography, Bathymetry, Mars, Mercury, Neptune, Pluto, Proxima Centauri, Saturn, Status Report, tau Ceti, TRAPPIST-1, Uranus, Venus, Water/Hycean Worlds & Oceanography

Classifications For Exoplanet and Exoplanetary Systems

by Keith CowingSeptember 17, 2024September 17, 2024

When a star is described as a spectral class G2V, we know its approximate mass, temperature, age, and size. At more than 5,700 exoplanets discovered, it is a natural developmental […]

Alpha Centauri, Exoplanets, -moons, -comets, Gas Giants, Science Fiction, Status Report

Stability of the Potential Super Jupiter in Alpha Centauri System

by Keith CowingJune 28, 2024June 28, 2024

The stability of potential exoplanets in binary star systems remains a critical challenge in celestial mechanics.

Alpha Centauri

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

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

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

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

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

Imaging Low-mass Planets Within The Habitable Zones Of Nearby Stars With Ground-based Mid-infrared Imaging

A Case Study of Interstellar Material Delivery: Alpha Centauri

A Sub-Earth-mass Planet Orbiting Barnard’s Star

Classifications For Exoplanet and Exoplanetary Systems

Stability of the Potential Super Jupiter in Alpha Centauri System

Preparing ExoMars For Rosalind Franklin Astrobiology Rover Delivery

Joint Dynamical-geophysical Evidence For A Limit Cycle In The Galilean Moons

JWST Transmission Spectroscopy Of TOI-3235 b: Challenges In Constraining Giant Planet Atmospheres Around M Dwarfs Amid Stellar Contamination

Searching For Habitable Exoplanets With Relative Astrometry (SHERA). I. The Case For Searching For Planets In Binary Star Systems

Callisto From JWST: CO2-rich Terrain On The Leading Hemisphere And Global Patterns Of H2O Ice