Author Topic: Pale Red Dot  (Read 63858 times)

Online matthewkantar

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Re: Pale Red Dot
« Reply #360 on: 12/14/2017 11:18 PM »
Three transits could be a long wait if the planet is as far out as our ice and gas giants.

Matthew

Offline Star One

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Re: Pale Red Dot
« Reply #361 on: 02/26/2018 07:41 PM »
Powerful Flare from Star Proxima Centauri Detected with ALMA

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ALMA data reveal that a powerful stellar flare erupted from Proxima Centauri last March. This space weather may make that system rather inhospitable to life after all.

https://public.nrao.edu/news/2018-alma-flare-proxima/

Offline Star One

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Re: Pale Red Dot
« Reply #362 on: 02/27/2018 08:02 PM »
Article discussing the possible implications of the above paper.

Proxima Flare May Force Rethinking of Dust Belts

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News of a major stellar flare from Proxima Centauri is interesting because flares like these are problematic for habitability. Moreover, this one may tell us something about the nature of the planetary system around this star, making us rethink previous evidence for dust belts there.

But back to the habitability question. Can red dwarf stars sustain life in a habitable zone much closer to the primary than in our own Solar System, when they are subject to such violent outbursts? What we learn in a new paper from Meredith MacGregor and Alycia Weinberger (Carnegie Institution for Science) is that the flare at its peak on March 24, 2017 was 10 times brighter than the largest flares our G-class Sun produces at similar wavelengths (1.3 mm).

https://www.centauri-dreams.org/2018/02/27/proxima-flare-may-force-rethinking-of-dust-belts/

Online hop

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Re: Pale Red Dot
« Reply #363 on: 04/09/2018 05:25 PM »
The First Naked-Eye Superflare Detected from Proxima Centauri

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Proxima b is a terrestrial-mass planet in the habitable-zone of Proxima Centauri. Proxima Centauri's high stellar activity however casts doubt on the habitability of Proxima b: sufficiently bright and frequent flares and any associated proton events may destroy the planet's ozone layer, allowing lethal levels of UV flux to reach its surface. In March 2016, the Evryscope observed the first naked-eye-visible superflare detected from Proxima Centauri. Proxima increased in brightness by a factor of ~68 during the superflare and released a bolometric energy of 10^33.5 erg, ~10X larger than any previously-detected flare from Proxima. Over the last two years the Evryscope has recorded 23 other large Proxima flares ranging in bolometric energy from 10^30.6 erg to 10^32.4 erg; coupling those rates with the single superflare detection, we predict at least five superflares occur each year. Simultaneous high-resolution HARPS spectroscopy during the Evryscope superflare constrains the superflare's UV spectrum and any associated coronal mass ejections. We use these results and the Evryscope flare rates to model the photochemical effects of NOx atmospheric species generated by particle events from this extreme stellar activity, and show that the repeated flaring is sufficient to reduce the ozone of an Earth-like atmosphere by 90% within five years. We estimate complete depletion occurs within several hundred kyr. The UV light produced by the Evryscope superflare therefore reached the surface with ~100X the intensity required to kill simple UV-hardy microorganisms, suggesting that life would struggle to survive in the areas of Proxima b exposed to these flares.
Edit:
Submitted, not yet reviewed, and the "naked eye" is a stretch. Undeniably a big flare through.
« Last Edit: 04/09/2018 06:01 PM by hop »

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