From what I heard, it wasn't the Pale Red Dot team who reported the finding.
I would imagine the previous thread was deleted due to embargo-breaking, so this probably will be too. Seems a bit toothpaste-back-in-tube now, but that's the site-owners choice.
The other thread is gone for some reason (I don't know what).
Quote from: Bubbinski on 08/14/2016 04:31 amThe other thread is gone for some reason (I don't know what). We had five threads on this and including "I think this site is an alien wacko site but I'm linking it anyway" posts (come on )We can have one thread....and there's about three merged into this one.
Quote from: Chris Bergin on 08/14/2016 01:54 pmQuote from: Bubbinski on 08/14/2016 04:31 amThe other thread is gone for some reason (I don't know what). We had five threads on this and including "I think this site is an alien wacko site but I'm linking it anyway" posts (come on )We can have one thread....and there's about three merged into this one.The joys of forum managing, eh Chris? Getting back to topic, the Pale Red Dot team isn't connected to the announcement, and on top of that we had the (likely) false alarm of a 'hot Earth' around Alpha Centauri B in the recent past. The team whose announcing this Proxima discovery better have some good evidence. Proxima has been thoroughly investigated; as an example PRD spent several months straight observing, which given a hypothetical Earth would be in a barely week-long orbit, should be ample to observe transits so long as you can meet the detection threshold and account for flare activity. All that is pretty certain about Proxima regarding planets is that anything Neptune-size and larger has been discounted, especially in close orbits. Given how, thanks largely to Kepler, we now know planets are indeed a common commodity for stars, it would be surprising NOT to find a planet around Proxima; we just need to verify if it can be Earthlike or not.
Just as a side point doesn't it appear that the term 'earth like' is getting especially horrible misused online in this case and leads to people imaging a planet just like Earth just with red skies. When there's no likely to be no evidence of anything like that at all.
Quote from: Star One on 08/15/2016 06:29 amJust as a side point doesn't it appear that the term 'earth like' is getting especially horrible misused online in this case and leads to people imaging a planet just like Earth just with red skies. When there's no likely to be no evidence of anything like that at all.Agreed. The bare minimum for an Earthlike planet should be a rocky planet with liquid water on the surface. We certainly don't call Venus Earthlike as an example, nor Europa where the liquid water is under the surface.
Agreed. The bare minimum for an Earthlike planet should be a rocky planet with liquid water on the surface. We certainly don't call Venus Earthlike as an example, nor Europa where the liquid water is under the surface.
Quote from: redliox on 08/15/2016 06:33 amAgreed. The bare minimum for an Earthlike planet should be a rocky planet with liquid water on the surface. We certainly don't call Venus Earthlike as an example, nor Europa where the liquid water is under the surface.I think there are serious problems for habitability around late-M dwarfs - they are very active in their early life and the models say they'll essentially lose their atmosphere and volatiles due to this. Add in the effect of flares and I'd be surprised if this really is habitable ... but still VERY exciting as it is a great prospect for testing a lot of the competing theories.On the leak, I suspect it could be about the Pale Red Dot campaign as they were into first round review stuff in early July, so end of August is feasible for paper acceptance. [ And if they had a null result, I rather suspect they wouldn't be quite so careful over embargo etc. ]--- Tony
Isn't one theory that a planet could possibly stay habitable around a red dwarf if it started out with an incredible thick atmosphere. But then it would probably also need an active magnetic field which I think tidal locking would preclude.
On the leak, I suspect it could be about the Pale Red Dot campaign as they were into first round review stuff in early July, so end of August is feasible for paper acceptance. [ And if they had a null result, I rather suspect they wouldn't be quite so careful over embargo etc. ]--- Tony
Quote from: Star One on 08/15/2016 09:45 amIsn't one theory that a planet could possibly stay habitable around a red dwarf if it started out with an incredible thick atmosphere. But then it would probably also need an active magnetic field which I think tidal locking would preclude.Yes, but (from memory) that relies on having a larger radius (>1.5Re) so there's a large initial H/He envelope ... there are also other models which rely on later inward migration into the HZ.But we're speculating on very poor data that could easily be wrong - the initial Der Spiegel article is hardly detailed ;-)--- Tony
Interestingly the palereddot team apparently said to discovermag that the leak wasn't from them. Doesn't mean it's not about them though I suppose. Also Interesting that MOST data is embargoed until around the same time...
Presuming Proxima DOES have a rocky planet in the habitable zone, we would be able to put these quandaries and theories to the test on whether or not M-dwarfs can be viable parents to Earthlike planets.
Quote from: Alpha_Centauri on 08/15/2016 09:59 amInterestingly the palereddot team apparently said to discovermag that the leak wasn't from them. Doesn't mean it's not about them though I suppose. Also Interesting that MOST data is embargoed until around the same time...The claim isn't from them is certain so far. Whether Proxima has a planet remains uncertain.
Quote from: Star One on 08/15/2016 09:45 amIsn't one theory that a planet could possibly stay habitable around a red dwarf if it started out with an incredible thick atmosphere. But then it would probably also need an active magnetic field which I think tidal locking would preclude.Yes, but (from memory) that relies on having a larger radius (>1.5Re) so there's a large initial H/He envelope ... there are also other models which rely on later inward migration into the HZ.
There is work that shows that, at least for some stellar masses and initial eccentricities of the planet, a magnetic field is the natural outcome for an M dwarf planet, because tidal heating cools the core which, in turn, generates a magnetic field. See here: http://arxiv.org/abs/1509.07452
So, in summary: it depends. I am sure that, once the Proxima paper is published, we will see detailed models exploring the possibility of the planet's habitability. If we are very lucky and there is a transit, we might even be able to refine these models to the point where they become believable and constraining. That would be something...
Quote from: Bynaus on 08/15/2016 07:29 pmThere is work that shows that, at least for some stellar masses and initial eccentricities of the planet, a magnetic field is the natural outcome for an M dwarf planet, because tidal heating cools the core which, in turn, generates a magnetic field. See here: http://arxiv.org/abs/1509.07452Thanks, I hadn't read that one ... I was more focused on the desiccation problem (http://arxiv.org/abs/1605.00616).QuoteSo, in summary: it depends. I am sure that, once the Proxima paper is published, we will see detailed models exploring the possibility of the planet's habitability. If we are very lucky and there is a transit, we might even be able to refine these models to the point where they become believable and constraining. That would be something...Yes, we are rather speculating in the dark ... and a transit would be fabulous (density and spectroscopy should constrain atmosphere models); without one, assuming the leak turns out to be accurate, I guess we'll have to wait for a star-shade.--- Tony
The team whose announcing this Proxima discovery better have some good evidence. Proxima has been thoroughly investigated; as an example PRD spent several months straight observing, which given a hypothetical Earth would be in a barely week-long orbit, should be ample to observe transits so long as you can meet the detection threshold and account for flare activity.
All that is pretty certain about Proxima regarding planets is that anything Neptune-size and larger has been discounted, especially in close orbits.
Given how, thanks largely to Kepler, we now know planets are indeed a common commodity for stars, it would be surprising NOT to find a planet around Proxima; we just need to verify if it can be Earthlike or not.
... and leads to people imaging a planet just like Earth but with red skies.