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Wow, amazing result. And talk about synchronicity - just last night I watched an interesting 2015 talk about the search for planets around Alpha Centauri using

Wow, amazing result. And talk about synchronicity - just last night I watched an interesting 2015 talk about the search for planets around Alpha Centauri using the radial velocity technique: https://www.youtube.com/watch?v=eieBXGpNYyE https://www.youtube.com/watch?v=eieBXGpNYyE The speaker even mentioned the previous incorrect HARPS announcement, which was later found to be an artefact due to the windowing function they used - a pretty embarrassing mistake. This new finding involves a completely different period: 11.2 days instead of the previous 3.24 day signal. Also, link to the Nature paper for the lazy: http://www.eso.org/public/archives/releases/sciencepapers/eso1629/eso1629a.pdf http://www.eso.org/public/archives/releases/sciencepapers/es...

WilliamDhalgren 10y ago
If you mean the previous claim of there being an Alpha Centauri Bb planet, later retracted, then this new finding involves a completely different star, not just a different period. This is around Proxima Centauri, the previous one was around Alpha Centauri B. Proxima is a really really small red dwarf, just 12.3% the mass of sun, while Alpha Centauri B is a K-type star, ie somewhat smaller than sun but not that much; around 90% of Sun's mass (And there's also Alpha Centauri A, 10% more massive than the sun). We're not even 100% sure that Proxima is part of the Alpha Centauri system, though I gather it's considered highly likely - it's pretty distant from the Alpha Centauri system, some 15 000 AU (1 AU = distance between Sun and Earth), almost a quarter of a light year.
- taliesinb 10y ago
  Yes, realized this and was editing my comment to reflect that but you beat me to it :). They did mention a previous signal from 2013, which got me confused with the spurious signal the SETI lecture mentioned.
  - WilliamDhalgren 10y ago
    heh, as you say; apparently there was a previous signal; reading the article about the find at centauri dreams, http://www.centauri-dreams.org/?p=36210 http://www.centauri-dreams.org/?p=36210 - and it does mention a pre-2016 Doppler signal with a period of 11.2 days around specifically Proxima, that was unconfirmed, and that this mission was to investigate that more closely. "The HARPS Pale Red Dot campaign was created to confirm or refute this 11.2-day signal" I'm just not sure if that's what the speaker in your video was talking about, of if the embarrasing mistake that was actually announced was the Alpha Centauri Bb planet (or maybe there were other candidates I didn't hear about); I'm gonna watch the lecture you linked and see. Thx for an interesting link, btw!
titzer 10y ago
If the period is 11.2 days, seems like there is a high chance that it is tidally locked to the star. If that's the case, that side is probably pretty roasting hot, the other quite cool. But maybe life near the edge is OK. Probably some interesting weather patterns there as well.
- BurningFrog 10y ago
  The weather is likely rough on the surface, but there could be plenty of good conditions for life under ground/water.
- the8472 10y ago
  There are other tidal locking modes than 1:1, like mercury has a 3:2 lock. Is that a possibility here?
- stcredzero 10y ago
  Probably some interesting weather patterns there as well. If by "interesting" you mean constant hurricane force convective flows going 24/7 between a scorching hell and frozen wastelands. Before there was soil, or sky, or any green thing, there was only the gaping abyss of Ginnungagap. This chaos of perfect silence and darkness lay between the homeland of elemental fire, Muspelheim, and the homeland of elemental ice, Niflheim. http://norse-mythology.org/tales/norse-creation-myth/ http://norse-mythology.org/tales/norse-creation-myth/ Perhaps it could be "the chaos of perfect silence," because the wind noises generated would render any unprotected human ears deaf within minutes?
  - craftkiller 10y ago
    Hmmm. We can generate heat and light using electricity, and we can generate electricity using windmills. Could we perhaps inhabit the dark side of a planet like this by building really sturdy windmills to harness those constant winds and then building an insulated, heated, artificially lit structure to grow plants and live in?
    - Natanael_L 10y ago

WilliamDhalgren 10y ago

If you mean the previous claim of there being an Alpha Centauri Bb planet, later retracted, then this new finding involves a completely different star, not just a different period. This is around Proxima Centauri, the previous one was around Alpha Centauri B. Proxima is a really really small red dwarf, just 12.3% the mass of sun, while Alpha Centauri B is a K-type star, ie somewhat smaller than sun but not that much; around 90% of Sun's mass (And there's also Alpha Centauri A, 10% more massive than the sun). We're not even 100% sure that Proxima is part of the Alpha Centauri system, though I gather it's considered highly likely - it's pretty distant from the Alpha Centauri system, some 15 000 AU (1 AU = distance between Sun and Earth), almost a quarter of a light year.

taliesinb 10y ago
Yes, realized this and was editing my comment to reflect that but you beat me to it :). They did mention a previous signal from 2013, which got me confused with the spurious signal the SETI lecture mentioned.
- WilliamDhalgren 10y ago
  heh, as you say; apparently there was a previous signal; reading the article about the find at centauri dreams, http://www.centauri-dreams.org/?p=36210 http://www.centauri-dreams.org/?p=36210 - and it does mention a pre-2016 Doppler signal with a period of 11.2 days around specifically Proxima, that was unconfirmed, and that this mission was to investigate that more closely. "The HARPS Pale Red Dot campaign was created to confirm or refute this 11.2-day signal" I'm just not sure if that's what the speaker in your video was talking about, of if the embarrasing mistake that was actually announced was the Alpha Centauri Bb planet (or maybe there were other candidates I didn't hear about); I'm gonna watch the lecture you linked and see. Thx for an interesting link, btw!

titzer 10y ago

If the period is 11.2 days, seems like there is a high chance that it is tidally locked to the star. If that's the case, that side is probably pretty roasting hot, the other quite cool. But maybe life near the edge is OK. Probably some interesting weather patterns there as well.

BurningFrog 10y ago
The weather is likely rough on the surface, but there could be plenty of good conditions for life under ground/water.
the8472 10y ago
There are other tidal locking modes than 1:1, like mercury has a 3:2 lock. Is that a possibility here?
stcredzero 10y ago
Probably some interesting weather patterns there as well. If by "interesting" you mean constant hurricane force convective flows going 24/7 between a scorching hell and frozen wastelands. Before there was soil, or sky, or any green thing, there was only the gaping abyss of Ginnungagap. This chaos of perfect silence and darkness lay between the homeland of elemental fire, Muspelheim, and the homeland of elemental ice, Niflheim. http://norse-mythology.org/tales/norse-creation-myth/ http://norse-mythology.org/tales/norse-creation-myth/ Perhaps it could be "the chaos of perfect silence," because the wind noises generated would render any unprotected human ears deaf within minutes?
- craftkiller 10y ago
  Hmmm. We can generate heat and light using electricity, and we can generate electricity using windmills. Could we perhaps inhabit the dark side of a planet like this by building really sturdy windmills to harness those constant winds and then building an insulated, heated, artificially lit structure to grow plants and live in?
  - Natanael_L 10y ago