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Thread: Alpha Centauri A: a possible planet?

  1. #1
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    Alpha Centauri A: a possible planet?

    Bright speck in space near Alpha Centauri A may be evidence of a planet, asteroids or dust – or a technical glitch.

    https://www.theguardian.com/science/...alpha-centauri
    https://www.scientificamerican.com/a...lpha-centauri/
    Do good work. —Virgil Ivan "Gus" Grissom

  2. #2
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    A planet in orbit of Alpha Centauri A seems unlikely, owing to the disruptive influence of very nearby Alpha Centauri B.
    The image in the Guardian article appears to be of an elongated object, not one massive enough to pull itself into a sphere.
    The idea that the object, if a planet, is the size of Neptune is presumably based on its brightness.
    I strongly suspect that, if the object is real, it is much closer than Alpha Centauri. This would be an odd coincidence, in itself, considering the odds of it randomly aligning with Earth and Alpha Centauri.

  3. #3
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    The original research paper discussing the discovery of the proposed Alpha Centauri Ab (admittedly a chance it isn't real).

    Imaging low-mass planets within the habitable zone of α Centauri

    K. Wagner, A. Boehle, P. Pathak, M. Kasper, R. Arsenault, G. Jakob, U. Kaufl, S. Leveratto, A.-L. Maire, E. Pantin, R. Siebenmorgen, G. Zins, O. Absil, N. Ageorges, D. Apai, A. Carlotti, É. Choquet, C. Delacroix, K. Dohlen, P. Duhoux, P. Forsberg, E. Fuenteseca, S. Gutruf, O. Guyon, E. Huby, D. Kampf, M. Karlsson, P. Kervella, J.-P. Kirchbauer, P. Klupar, J. Kolb, D. Mawet, M. N'Diaye, G. Orban de Xivry, S. P. Quanz, A. Reutlinger, G. Ruane, M. Riquelme, C. Soenke, M. Sterzik, A. Vigan, T. de Zeeuw

    Giant exoplanets on wide orbits have been directly imaged around young stars. If the thermal background in the mid-infrared can be mitigated, then exoplanets with lower masses can also be imaged. Here we present a ground-based mid-infrared observing approach that enables imaging low-mass temperate exoplanets around nearby stars, and in particular within the closest stellar system, {\alpha} Centauri. Based on 75-80% of the best quality images from 100 hours of cumulative observations, we demonstrate sensitivity to warm sub-Neptune-sized planets throughout much of the habitable zone of {\alpha} Centauri A. This is an order of magnitude more sensitive than state-of-the-art exoplanet imaging mass detection limits. We also discuss a possible exoplanet or exozodiacal disk detection around {\alpha} Centauri A. However, an instrumental artifact of unknown origin cannot be ruled out. These results demonstrate the feasibility of imaging rocky habitable-zone exoplanets with current and upcoming telescopes.

    https://arxiv.org/abs/2102.05159
    Do good work. —Virgil Ivan "Gus" Grissom

  4. #4
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    If confirmed, this planet will be classified as a super-earth. This can become a problem for modern models of the formation of such planets since according to them, such bodies should arise near the snow line, that is, the distance at which volatiles go into a solid state.

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