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 Post subject: Re: proxima fever!
PostPosted: Sat Sep 10, 2016 12:45 pm 
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The Book That Predicted Proxima b [Excerpt]

http://www.scientificamerican.com/artic ... b-excerpt/

Not surprised it's a Stephen Baxter novel.

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 Post subject: Re: proxima fever!
PostPosted: Tue Sep 13, 2016 4:46 pm 
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How we found a planet orbiting Proxima Centauri

http://scitation.aip.org/content/aip/ma ... /PT.5.2048

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 Post subject: Re: proxima fever!
PostPosted: Tue Sep 20, 2016 7:35 am 
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Do Dolphins Dream of Space Travel?

http://blogs.scientificamerican.com/gue ... ce-travel/

Quote:
In 2005, however, a small workshop was held at the SETI Institute, with the intent of reevaluating the decades of planetary party-pooping— and (Lucianne Walkowicz), as a particularly lucky young graduate student, got to attend. Over the week, we examined these assumptions in a fresh light, eventually concluding that none of those supposed showstoppers (flares, tidal locking, et al.) are really all that show-stopping.

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 Post subject: Re: proxima fever!
PostPosted: Tue Sep 20, 2016 8:12 am 
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Flares on Proxima Centauri

http://www.ifweassume.com/2016/08/flare ... a-cen.html

Quote:
A less talked about aspect of this important low mass star is it's rotation. Proxima rotates quite slowly, 83 days compared to ~25 days on the Sun. Typically we see an inverse connection between rotation and flare rates, with short rotation period (fast spinning) stars showing higher flare rates. Since rotation probably helps drive the star's magnetic field, this is thought to be an age effect: stars spin slower as they age (just like a child's top spinning on a table), which also leads to lower flare rates as they get older. Proxima flies in the face of this assumption, and flares A LOT compared to its rotation period.

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 Post subject: Re: proxima fever!
PostPosted: Fri Sep 23, 2016 1:51 pm 
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EXCLUSIVE: Mark Zuckerberg, Yuri Milner and Stephen Hawking to begin $100 million search for alien life on a nearby Earth-like planet

http://www.dailymail.co.uk/sciencetech/ ... lanet.html

Quote:
Early next month, the Breakthrough Listen team will look for radio emissions that differ from the natural background noise using the Parkes Observatory in Australia.

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 Post subject: Re: proxima fever!
PostPosted: Thu Sep 29, 2016 4:58 pm 
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How to See Proxima b

http://www.scientificamerican.com/artic ... proxima-b/

Quote:
Unfortunately, a new study released today led by astronomer David Kipping of Columbia University has all but ruled out the possibility of transits for Proxima b. Kipping and his colleagues went searching for its transits in data gathered by Canada’s MOST space telescope, and even found what seemed to be a compelling signal—but additional data from the ground-based HATSouth telescope array suggested the signal was due to Proxima Centauri’s flares rather than any transiting world. “Although we found a candidate transit in the MOST data, HATSouth data rules it out at a confidence level of 70 to 90 percent,” Kipping says. “I would now give it less than a 1 percent chance of being a transiting planet. That sounds very small, but scientists prefer to deal with numbers like 0.0001 percent when we talk about ruling things out, so a more conclusive answer will probably require more data.” That could come soon, if astronomers use NASA’s Spitzer Space Telescope to learn once and for all whether Proxima b transits its star.


More at the link.

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 Post subject: Re: proxima fever!
PostPosted: Mon Oct 03, 2016 5:07 pm 
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Possible Internal Structures and Compositions of Proxima Centauri b

http://astrobiology.com/2016/10/possibl ... uri-b.html

Quote:
The minimum value is obtained considering a 1.10 M? Mercury-like planet with a 65% core mass fraction, whereas the highest radius is reached for 1.46 M? with 50% water in mass, constituting an ocean planet. Although this range of radii still allows very different planet compositions, it helps characterizing many aspects of Proxima Centauri b, such as the formation conditions of the system or the current amount of water on the planet. This work can also help ruling out future measurements of the planet's radius that would be physically incompatible with a solid planetary body.


The arXiv paper: https://arxiv.org/abs/1609.09757

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 Post subject: Re: proxima fever!
PostPosted: Thu Oct 06, 2016 4:34 pm 
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Planet in star system nearest our Sun 'may have oceans'

http://phys.org/news/2016-10-planet-sta ... ceans.html

Should there be any question about the affect of stellar flares on Proxima b, they're already working on the problem. Here's the first paper:

The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf

https://arxiv.org/abs/1006.0022

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 Post subject: Re: proxima fever!
PostPosted: Tue Oct 11, 2016 9:35 am 
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Scientists say they have a $25 million plan to image Alpha Centauri’s planets

http://arstechnica.com/science/2016/10/ ... -centauri/

Quote:
Unlike the Kepler Space Telescope—which monitored 100,000 stars and looked for slight dimming to determine when planets passed in front of their parent stars—Project Blue will use high-contrast imaging. Technical studies have shown that, with an advanced coronagraph to block light from the stars and data processing techniques, such a telescope could reject light from the two stars at a rate of 10 billion to one. This is sufficient to allow direct imaging of a planet with observations made over the course of several years. Put another way, such an observation system is akin to detecting a firefly next to a lighthouse 10 miles away.


Caveat: crowdfunding

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 Post subject: Re: proxima fever!
PostPosted: Tue Oct 11, 2016 7:49 pm 
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Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri

https://arxiv.org/abs/1610.03447

This is interesting, especially in light of that article about how Jupiter, Earth, and Venus aligning to have an effect upon the solar cycle.

Forum link for the curious: viewtopic.php?f=3&t=1031

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 Post subject: Re: proxima fever!
PostPosted: Wed Oct 12, 2016 4:11 pm 
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Proxima Centauri might be more Sun-like than we thought

https://astronomynow.com/2016/10/11/pro ... e-thought/

Quote:
The new study finds that Proxima Centauri undergoes a similar cycle lasting seven years from peak to peak. However, its cycle is much more dramatic. At least a full one-fifth of the star’s surface is covered in spots at once. Also, some of those spots are much bigger relative to the star’s size than the spots on our Sun.

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 Post subject: Re: proxima fever!
PostPosted: Wed Oct 12, 2016 5:10 pm 
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A nice online article at Sky & Telescope...

http://www.skyandtelescope.com/astronomy-news/proxima-centauri-sun-like-cycle

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 Post subject: Re: proxima fever!
PostPosted: Wed Oct 19, 2016 4:56 pm 
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How Big Is Proxima Centauri’s Planet?

http://www.slate.com/blogs/bad_astronom ... uri_b.html

Quote:
The only way we know to measure the physical size of a planet is if it transits its parent star; that is, the orbit of the star is edge-on as seen from Earth, so we see the planet pass in front of the star once per orbit.


Quote:
Knowing this, some astronomers observed Proxima using the Microwave and Oscillations of Stars Telescope (or MOST), a ‘scope with a 15 centimeter mirror that orbits the Earth. MOST is tiny; it only has a mass of 53 kg (that’s less than the mass of a typical adult human) and has a relatively small mirror, but being in space means it’s very stable. It doesn’t have to worry about peering through Earth’s atmosphere, which is wiggly and wavy. That means even a small ‘scope can make very precise measurements of a star’s brightness.

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 Post subject: Re: proxima fever!
PostPosted: Tue Oct 25, 2016 4:35 pm 
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A Microlensing Opportunity for Centauri A

http://www.centauri-dreams.org/?p=36537

Quote:
A team of French astronomers led by Pierre Kervella (CNRS/Universidad de Chile) is behind this new study, which involved fine-tuning our knowledge of the trajectories of Centauri A and B. Remember that we see gravitational lensing when a massive object like a star distorts the spacetime around it, so that light from the more distant object must follow a curved path to reach us. The amount of mass in the closer star affects the extent of this deflection, and when one or more planets orbit the star, they become theoretically detectable.

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 Post subject: Re: proxima fever!
PostPosted: Mon Oct 31, 2016 7:39 pm 
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As posted earlier, astronomers proposed how to see if Proxima b has an atmosphere.

Let's step up the game:

Prospects for Characterizing the Atmosphere of Proxima Centauri b

Quote:
The newly detected Earth-mass planet in the habitable zone of Proxima Centauri could potentially host life - if it has an atmosphere that supports surface liquid water. We show that thermal phase curve observations with the James Webb Space Telescope (JWST) from 5-12 microns can be used to test the existence of such an atmosphere. We predict the thermal variation for a bare rock versus a planet with 35% heat redistribution to the nightside and show that a JWST phase curve measurement can distinguish between these cases at 4σ confidence, assuming photon-limited precision. We also consider the case of an Earth-like atmosphere, and find that the ozone 9.8 micron band could be detected with longer integration times (a few months). We conclude that JWST observations have the potential to put the first constraints on the possibility of life around the nearest star to the Solar System.


https://arxiv.org/abs/1608.07345

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 Post subject: Re: proxima fever!
PostPosted: Mon Nov 14, 2016 5:29 pm 
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Proxima's orbit around Alpha Centauri

http://harvard.voxcharta.org/2016/11/13 ... -centauri/

Quote:
Owing to recent high precision radial velocity measurements and the revision of the parameters of the Alpha Cen pair, we show that Proxima and Alpha Cen are gravitationally bound with a high degree of confidence.


Original link to the paper at arXiv.

https://arxiv.org/abs/1611.03495

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 Post subject: Re: proxima fever!
PostPosted: Tue Nov 15, 2016 2:41 pm 
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Project Blue: Imaging Alpha Centauri Planets

http://www.centauri-dreams.org/?p=36621

Quote:
“We’re at an incredible moment in history, where for the first time, we have the technology to actually find another Earth,” said Morse. “Just as exciting — thanks to the power of crowdfunding — we can open this mission to everyone. With the Project Blue consortium, we are bringing together the technical experts who can build and launch this telescope. Now we want to bring along everyone else as well. This is a new kind of space initiative — to achieve cutting-edge science for low cost in just a few years, and it empowers us all to participate in this moment of human discovery.”

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 Post subject: Re: proxima fever!
PostPosted: Tue Nov 15, 2016 3:10 pm 
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This is neat!

How to Directly Image a Habitable Planet Around Alpha Centauri with a ~30-45cm Space Telescope

Space being the operative word here.

Quote:
Several mission concepts are being studied to directly image planets around nearby stars. It is commonly thought that directly imaging a potentially habitable exoplanet around a Sun-like star requires space telescopes with apertures of at least 1m. A notable exception to this is Alpha Centauri (A and B), which is an extreme outlier among FGKM stars in terms of apparent habitable zone size: the habitable zones are ~3x wider in apparent size than around any other FGKM star. This enables a ~30-45cm visible light space telescope equipped with a modern high performance coronagraph or starshade to resolve the habitable zone at high contrast and directly image any potentially habitable planet that may exist in the system.


https://arxiv.org/abs/1510.02479

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 Post subject: Re: proxima fever!
PostPosted: Tue Nov 29, 2016 3:31 pm 
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Alpha Centauri Gets a New Moniker as 227 Star Names Are Clarified

http://www.space.com/34835-alpha-centau ... names.html

Bye Alpha Centauri! Hello, Rigil Kentaurus!

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 Post subject: Re: proxima fever!
PostPosted: Wed Nov 30, 2016 3:58 pm 
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There's no new name here. For some time, Sky Tools has called it Rigel Kentaurus and Stellarium calls it Rigil Kent, so at most, the spelling and full name have been standardized. Alpha Centauri was, and still is, the Bayer designation for that star -- just like we can call another popular star Mirach or Beta Andromedae (but now with a standardized spelling for Mirach).

A much better article on the IAU star-naming standardization can be found at Sky & Telescope...

http://www.skyandtelescope.com/astronomy-news/iau-standardizes-212-traditional-star-names/

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 Post subject: Re: proxima fever!
PostPosted: Fri Dec 02, 2016 4:33 pm 
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Twinkle, Twinkle Little [Insert Name Here]

http://www.nytimes.com/2016/12/02/scien ... stars.html

Same story, different outlet

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 Post subject: Re: proxima fever!
PostPosted: Sun Dec 11, 2016 10:13 pm 
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Two relevant abstracts for those who are interested.

The Space Weather of Proxima Centauri b

https://arxiv.org/abs/1609.09076

Quote:
A planet orbiting in the "habitable zone" of our closest neighboring star, Proxima Centauri, has recently been discovered, and the next natural question is whether or not Proxima b is "habitable". Stellar winds are likely a source of atmospheric erosion that could be particularly severe in the case of M dwarf habitable zone planets that reside close to their parent star. Here we study the stellar wind conditions that Proxima b experiences over its orbit. We construct 3-D MHD models of the wind and magnetic field around Proxima Centauri using a surface magnetic field map for a star of the same spectral type and scaled to match the observed ~ 600 G surface magnetic field strength of Proxima. We examine the wind conditions and dynamic pressure over different plausible orbits that sample the constrained parameters of the orbit of Proxima b. For all the parameter space explored, the planet is subject to stellar wind pressures of more than 2000 times those experienced by Earth from the solar wind. During an orbit, Proxima b is also subject to pressure changes of 1 to 3 orders of magnitude on timescales of a day. Its magnetopause standoff distance consequently undergoes sudden and periodic changes by a factor of 2 to 5. Proxima b will traverse the interplanetary current sheet twice each orbit, and likely crosses into regions of subsonic wind quite frequently. These effects should be taken into account in any physically realistic assessment or prediction of its atmospheric reservoir, characteristics and loss.


On the Orbital Inclination of Proxima Centauri b

https://arxiv.org/abs/1612.02872

Quote:
The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for studies of characterization and near-term follow-up prospects. The recent discovery of a terrestrial planet candidate orbiting Proxima Centauri presents numerous opportunities for studying a Super-Earth within our own stellar backyard. One of the remaining ambiguities of the discovery is the true mass of the planet since the discovery signature was obtained via radial velocities. Here we describe the effect of orbital inclination on the Proxima Centauri planet, in terms of mass, radius, atmosphere, and albedo. We calculate the astrometric, angular separation, and reflected light properties of the planet including the effects of orbital eccentricity. We further provide dynamical simulations that show how the presence of additional terrestrial planets within the Habitable Zone varies as a function of inclination. Finally, we discuss these effects in the context of future space-based photometry and imaging missions that could potentially detect the planetary signature and resolve the inclination and mass ambiguity of the planet.

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 Post subject: Re: proxima fever!
PostPosted: Fri Dec 23, 2016 10:18 am 
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Orbit of Proxima Centauri Determined After 100 Years

https://www.eso.org/public/announcements/ann16089/

Quote:
Now three astronomers, Pierre Kervella, Frédéric Thévenin and Christophe Lovis, have concluded that the three stars do indeed form a bound system. In the century since it was discovered, Proxima Centauri’s faintness has made it extremely difficult to reliably measure its radial velocity — the speed at which it moves towards and away from Earth. But now ESO’s planet-hunting HARPS instrument has provided an extremely precise measurement of Proxima Centauri’s radial velocity, and even greater accuracy has been achieved by accounting for other subtle effects .

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 Post subject: Re: proxima fever!
PostPosted: Mon Jan 09, 2017 4:52 pm 
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On the Orbital Inclination of Proxima Centauri b

http://iopscience.iop.org/article/10.38 ... ld.iop.org

Quote:
The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for studies of characterization and near-term follow-up prospects. The recent discovery of a terrestrial planet candidate orbiting Proxima Centauri presents numerous opportunities for studying a super-Earth within our own stellar backyard. One of the remaining ambiguities of the discovery is the true mass of the planet since the discovery signature was obtained via radial velocities. Here, we describe the effect of orbital inclination on the Proxima Centauri planet, in terms of mass, radius, atmosphere, and albedo. We calculate the astrometric, angular separation, and reflected light properties of the planet including the effects of orbital eccentricity. We further provide dynamical simulations that show how the presence of additional terrestrial planets within the Habitable Zone varies as a function of inclination. Finally, we discuss these effects in the context of future space-based photometry and imaging missions that could potentially detect the planetary signature and resolve the inclination and mass ambiguity of the planet.

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 Post subject: Re: proxima fever!
PostPosted: Tue Jan 10, 2017 10:26 am 
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VLT to Search for Planets in Alpha Centauri System

https://www.eso.org/public/news/eso1702/

Quote:
ESO has signed an agreement with the Breakthrough Initiatives to adapt the Very Large Telescope instrumentation in Chile to conduct a search for planets in the nearby star system Alpha Centauri. Such planets could be the targets for an eventual launch of miniature space probes by the Breakthrough Starshot initiative.

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