Two more planet candidates detected by the Planet Hunters announced at the AAS 219.
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Two more planet candidates detected by the Planet Hunters announced at the AAS 219.
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^
Great news.That 284-day candidate is truly exciting, should it be confirmed.
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Kepler-34 and Kepler-35, two more circumbinary planets.
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Smallest transiting exoplanets around a Barnard star analogue KOI-961. The planet radii are mere 0.78, 0.73 and 0.57 REarth.
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Microlensing observations suggest that planets are very common and are likely more numerous than stars in the Milky Way.
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No surprise there. Smaller astronomical objects are generally more common. Small stars are much more common than big stars. Asteroids are much more common than planets. There may be a reversal of this tendency for objects in the super-jovian and brown dwarf mass ranges. I anticipate that Jovians will be rarer than Saturns will be rarer than Neptunes will be rarer than super-Earths will be rarer than sub-Earths. I wouldn't be surprised if there are more free-planets than there are stars.Originally Posted by Kullat Nunu
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"Fun papers in arXiv" has the paper that article is based on. Just went up.
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Well, this one is interesting!
Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548
We report here on the discovery of stellar occultations, observed with Kepler, that recur periodically at 15.685 hour intervals, but which vary in depth from a maximum of 1.2% to a minimum that can be less than 0.2%. The star that is apparently being occulted is KIC 12557548, a V = 16 magnitude K dwarf with T_eff = 4400 K. The out-of-occultation behavior shows no evidence for ellipsoidal light variations, indicating that the mass of the orbiting object is less than ~3 M_J. Because the eclipse depths are highly variable, they cannot be due solely to transits of a single planet with a fixed size. We discuss but dismiss a scenario involving a binary giant planet whose mutual orbit plane precesses, bringing one of the planets into and out of a grazing transit. This scenario seems ruled out by the dynamical instability that would result from such a configuration. The much more likely explanation involves macroscopic particles - e.g., dust, possibly in the form of micron-sized pyroxene grains - escaping the atmosphere of a slowly disintegrating planet not much larger than Mercury in size. The planetary surface is hot enough to sublimate; the resultant silicate vapor accelerates off the planet via a Parker-type thermal wind, dragging dust grains with it. We infer a mass loss rate from the observations of order ~1 M_earth/Gyr, with a dust-to-gas ratio possibly of order unity. For our fiducial 0.1 M_earth planet (twice the mass of Mercury), the evaporation timescale may be ~0.2 Gyr. Smaller mass planets are disfavored because they evaporate still more quickly, as are larger mass planets because they have surface gravities too strong to sustain outflows with the requisite mass-loss rates. The occultation profile evinces an ingress-egress asymmetry that could reflect a comet-like dust tail trailing the planet; we present simulations of such a tail.
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Very interesting! I wonder how old the star is. I wasn't able to find if they mentioned it. Does anyone know how to calculate the absolute visual magnitude of a star with only knowing the parameters given by the Kepler data? Or how these guys found it?
The KIC lists magnitudes of g=16.7, r=15.6, i=15.3,
and z= 15.1 for star 12557548. From this we estimate
the V magnitude is 16.2 (Windhorst et al. 1991). If we
take the absolugte visual magnitude of the K star to be
+7.6 (with Ls ' 0:14L ), and correct for an estimated
AV ' 0:22, this puts the object at a distance of about
470 pc.
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Probing the interiors of the ice giants: Shock compression of water to 700 GPa and 3.8 g/ccm
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This proliferation of tiny planets is becoming quite confusing... And none of them confirmed with radial velocity measurements.
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A Jovian planet detected orbiting the white dwarf/red dwarf binary RR Cae using transit timings. Another planet with long orbit (p>26.3 years) suspected.
Seems that planets are common in such systems.
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A Circumbinary Planet in Orbit Around the Short-Period White-Dwarf Eclipsing Binary RR Cae
The central binary has a period of only 7.3h. The (probable) planet has mass >= 4.2+/-0.4 MJ and period 11.9 years. If the system is co-planar the true mass should be close to the lower limit because the binary is eclipsing.
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arxiv.org/abs/1201.5075We report the discovery of HAT-P-38b, a Saturn-mass exoplanet transiting the V=12.56 dwarf star GSC 2314-00559 on a P = 4.6404 d circular orbit. The host star is a 0.89Msun late G-dwarf, with solar metallicity, and a radius of 0.92Rsun. The planetary companion has a mass of 0.27MJ, and radius of 0.82RJ. HAT-P-38b is one of the closest planets in mass and radius to Saturn ever discovered.
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I noticed this paper during my weekly survey of arXiv papers, but I couldn't put a finger on anything in particular about it. I'm curious - what in your opinion makes this an "interesting" extrasolar planet discovery?
Generally, I like this thread but I don't always find the "interesting" aspect of the listed discoveries self-evident. Sometimes, I could use a little tip.
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If nothing else, it informs folks who find any discovery of an extrasolar planet interesting. I personally find any discovery that was found by folding light curve data onto itself and studying those results is fascinating. Here is an explanation of the "Box Least-Squares method" that was used.
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The new phenomenon of "exoplanet ennui"
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^
LOL. Much as I love exoplanets, I'm sure the day will come (maybe even within my own lifetime) when exoplanets become the new "vermin of the skies".
Imagine: "Another Earthlike planet? If you're not seeing the red edge and free oxygen, Myers, round file it with the rest..."
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That makes 39 planets discovered this year!
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Anyone know what the total number of discoveries was in 2011?That makes 39 planets discovered this year!
At the rate we're going we're going to have about 1 planet discovered per day in 2012 on average.. very exciting!
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2010 : 114 (0.31 / day)
2011 : 188 (0.51 / day)
2012 : 39 (1.39 / day)
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According to the Extrasolar Planets Encyclopaedia, a total of 188 planets were discovered in 2011 (histogram view). For the year 2010 the number is 114, so the jump is huge. The discovery rate looks exponential! Of course, the values are not constant so some candidates may be removed (or new ones added).
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The binary star KOI-284 may have transiting planets around both stars. Not confirmed yet, though.
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As a non-planetary scientist, I concur.
If it's another "hot Jupiter" that's been discovered, what makes it different from the other "hot Jupiters" that we already know about? What makes the particular world in a given link distinctive? Just saying that it's there doesn't necessarily make it interesting. Even a quick sentence saying, "Based on its mass, we believe this world is made entirely of marshmallow fluff" or "Based on its mass and orbital period, we believe this world may get swallowed by its star in less than 1000 years" would be very helpful and enlightening to us lay folk.
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I think contributing a complaint about another posters link publicly is contributing less than the link itself. Feel free to PM me rather than call out my posting technique.
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Whoa, please don't take my post as a personal attack against you, because that's not what was intended! I've seen others do it, too, which is why I didn't include your post in the quote: it's not about you personally, and I sincerely apologize if you saw it as such.
I'm just asking for the same sort of treatment for extrasolar planet discoveries as BAUT suggests for linking to other content: instead of just providing the link, also provide a brief description of what's being linked to and why we might think it's interesting.
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I consider a typical extrasolar planet discovery "uninteresting" when we start finding Earth-like planets in thousands.
700+ planets, even though impressive, are not that much after all.
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Couldn't agree more. Finding 0.0000003645 % of the total 200,000,000,000 estimated planets out there just doesn't sing boredom to me yet either. I don't think my exoboredom will kick in until we've found at least 0.000025 %!I consider a typical extrasolar planet discovery "uninteresting" when we start finding Earth-like planets in thousands.
700+ planets, even though impressive, are not that much after all.
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