"These suggest that the planet candidate is on an eccentric (e~0.4)
orbit significantly inclined with respect to Alpha Cen AB orbital
plane (i mutual ~50 degrees, or ~130 degrees). Based on the photometry
and orbital properties, the planet candidate could have a temperature
of 225 K, a radius of 1-1.1 (Jupiter) and a mass between 90-150 (Earth), >consistent with RV limits."
https://arxiv.org/abs/2508.03814
For people not familiar with the Kelvin temperature scale, 225 K is the >temperature of a very cold giraffe.
On Sat, 9 Aug 2025 08:36:41 -0400 (EDT), jdnicoll@panix.com (James
Nicoll) wrote:
"These suggest that the planet candidate is on an eccentric (e~0.4)
orbit significantly inclined with respect to Alpha Cen AB orbital
plane (i mutual ~50 degrees, or ~130 degrees). Based on the photometry
and orbital properties, the planet candidate could have a temperature
of 225 K, a radius of 1-1.1 (Jupiter) and a mass between 90-150 (Earth), >>consistent with RV limits."
https://arxiv.org/abs/2508.03814
For people not familiar with the Kelvin temperature scale, 225 K is the >>temperature of a very cold giraffe.
Frozen solid, I should think.
And I am sure the planet candidate could be a lot of things. Those
proposed here, presumably, have at least some sort of data to support
them.
After all, I /could/ have wings. But I don't.
Perhaps "might have" would be better than "could have", although I
suppose it doesn't make much difference any more.
"These suggest that the planet candidate is on an eccentric (e~0.4)
orbit significantly inclined with respect to Alpha Cen AB orbital
plane (i mutual ~50 degrees, or ~130 degrees). Based on the photometry
and orbital properties, the planet candidate could have a temperature
of 225 K, a radius of 1-1.1 (Jupiter) and a mass between 90-150 (Earth), consistent with RV limits."
https://arxiv.org/abs/2508.03814
For people not familiar with the Kelvin temperature scale, 225 K is the temperature of a very cold giraffe.
For people not familiar with the Kelvin temperature scale, 225 K is the temperature of a very cold giraffe.
Jupiter "should" emit at 105K but actually emits at 125. This much
larger hypothesized planet may well have a much greater output.
It is conceivable that a moon of this planet could have a strong enough greenhouse effect to be habitable, but it would probably need to be too
large to be realistic.
That's a lot of ifs, but not too many for an SF novel.
I did a brief search for the amount of tidal heating and came up with no. . .
hard numbers, but an estimate of less than one W/M**. Do you know
anything more concrete?
It's frustrating how many of these sources talk around the figure you
need to know. These non-climate people!
In article <unqe9k93p83m8ai52b8s70tvfduqv4b73v@4ax.com>,
Paul S Person <psperson@old.netcom.invalid> wrote:
On Sat, 9 Aug 2025 08:36:41 -0400 (EDT), jdnicoll@panix.com (James
Nicoll) wrote:
"These suggest that the planet candidate is on an eccentric (e~0.4)
orbit significantly inclined with respect to Alpha Cen AB orbital
plane (i mutual ~50 degrees, or ~130 degrees). Based on the photometry >>>and orbital properties, the planet candidate could have a temperature
of 225 K, a radius of 1-1.1 (Jupiter) and a mass between 90-150 (Earth), >>>consistent with RV limits."
https://arxiv.org/abs/2508.03814
For people not familiar with the Kelvin temperature scale, 225 K is the >>>temperature of a very cold giraffe.
Frozen solid, I should think.
And I am sure the planet candidate could be a lot of things. Those
proposed here, presumably, have at least some sort of data to support
them.
After all, I /could/ have wings. But I don't.
Perhaps "might have" would be better than "could have", although I
suppose it doesn't make much difference any more.
It's very early days, thus the "this interpretation fits the data",
not "this is what Alpha Centauri A is like".
It's about as cold as Mars, I think.
One of the Alpha Centaurian worlds in Charles Pellegrino's
_Flying to Valhalla_ (1993) is an ice world with a subsurface ocean.
Gur angvirf nera'g fcnpr snevat lrg, ohg gurl pbzr hc guebhtu gur
vpr naq dhvpxyl qvfnffrzoyr gur cebor frag qbja, ng juvpu cbvag bhe
cebgntbavfgf pbafvqre vg cehqrag gb Xrffyre-flaqebzr gurz, jvgu
nagvznfggre ab yrff.
That wasn't nice of them.
AKA, the 'Dark Forest' variant on the Fermi Paradox.
The freezing point of water at one atmosphere is 273.15 K.
So 225 K is very, very cold, -48 C.
That temperature occurs routinely in mostly the Dakotas and Minnesota in
the lower 48 of the USA but not for very long.
-48C is -54.4F. The coldest that the Twin Cities got during my time there
was -27F in January 1994.[1] Fortunately, I was in Europe for most of that >month. The folks I was working with were going to be coming to the Cities
the following month, so I spent a lot of our breaks telling them horror >stories about what they were in for.
Since the Twin Cities aren't Minnesota, let's look at "the nation's icebox," >International Falls, Minnesota. We see that the record low was -55F, a
record set in 1909.[2]
On Sat, 9 Aug 2025 14:48:06 -0500, Lynn McGuire
<lynnmcguire5@gmail.com> wrote:
The freezing point of water at one atmosphere is 273.15 K.
So 225 K is very, very cold, -48 C.
That temperature occurs routinely in mostly the Dakotas and Minnesota in >>the lower 48 of the USA but not for very long.
Been there done that - in Manitoba which is directly north of the
states you name. There's typically about two weeks in winter like that
with the rest of winter being about 20-25 degrees warmer than that.
(Still bluddy cold but at least bearable with proper clothing. I once
crossed Portage Avenue (6 lanes) in Winnipeg in -30 wearing nothing
heavier than a heavy sweater and ran most of the way - this is the
kind of thing you do in your 20s but definitely wouldn't try now)
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