Talk:OGLE-2005-BLG-390Lb

message: * We probably shouldn't write that much about microlensing; it has its own article, and readers can go there if they need or want more information. Ghent 22:06, 25 January 2006 (UTC)
thread_title: Untitled

message: Probably shouldn't have all this speculative stuff in there, all we have is a mass and projected separation - we don't know if it has a rocky core or not, nor even if it is a terrestrial. Chaos syndrome 23:59, 25 January 2006 (UTC)
replies: text: We also have spectral type of it's star. Thus probabls range of surface temperatures can be estimated. Some of the referances are definatly classifying it as rocky - including the ESO - although how they derive that, I'm not sure - Beowulf314159 00:04, 26 January 2006 (UTC)

text: Toss in the fact that they were saying that Glise 876 d could not be a Jovian type world because it's "low mass" - 7.5 times terran mass - would not retain the atmosphere of a gas giant. This world is smaller yet. - Beowulf314159 00:08, 26 January 2006 (UTC)
replies: text: However this planet is a lot colder, which aids gas retention as the molecules in the atmosphere aren't bouncing around so fast. After applying a few worldbuilding rules-of-thumb I get that the planet could probably retain hydrogen in the atmosphere, though this isn't by any means rigorous, and would count as original research anyway. The whole implication that this is a terrestrial-type planet seems to only be present in the press releases, not the discovery paper. Chaos syndrome 10:39, 26 January 2006 (UTC)

text: As long as we make it clear that it's not been proven yet, it can't hurt. The information so far is making what the *official announcement* states, quite possible. Ghent 07:02, 26 January 2006 (UTC)
thread_title:  Speculation 

message: Does anyone know that? I believe it doesen't even have a name, does it (don't know how this works)? anyway, that would be something nice to be in the article. algumacoisaqq 01:34, 26 January 2006 (UTC)
replies: text: It looks like the name of the star is OGLE-2005-BLG-390L (at least, its the name given in the Extrasolar Planets Encyclopaedia), which, by the way, has got its own article. — Poulpy 10:46, 26 January 2006 (UTC)
replies: text: The star is very inconspicuous -- one of the hundreds of millions visible towards the Galactic bulge. The image  of the star illustrates that well. Therefore it did not have a name before the lensing event.--Jyril 12:29, 27 January 2006 (UTC)
thread_title:  Which red dwarf? 

message: "the surface is made of a frozen liquid" — i.e. "the surface is solid"?? Joestynes 12:49, 26 January 2006 (UTC)
replies: text: I've changed it to read "frozen volatiles," which is more consistent with astronomers' usage in such cases. --Jeff Medkeff | Talk 13:09, 26 January 2006 (UTC)
thread_title:  frozen liquid 

message: Planetary detections through doppler means have the potential to follow the delta through the entire orbit, from red shifted, to the mean, to blue shifted, and back. So I take the point about microlensing not being repeatable, to the extent that other observatories cannot go look in a month or a year and potentially make observations that disprove the hypothesis. However, the article summarizes this distinction as non-repeatability and, as I read it, it seems to suggest that the microlensing event won't repeat. At a distance of ~28ly or whatever, and given normal proper motions for the star, it would be very surprising if it wouldn't detectably repeat one planetary orbital period later. A nit, but still. --Jeff Medkeff | Talk 13:09, 26 January 2006 (UTC)
replies: text: During a microlensing event the star and especially the planet must travel over the disk of the background star, which needs extremely accurate alignment. That is why these events are practically unique. The lensing star moves relatively quickly (the whole lensing event lasts only a few months at maximum), enough that the planet cannot cross the background star again.--Jyril 12:36, 27 January 2006 (UTC)
thread_title: Repeatability

message: Can we please decide this once and for all?  The ESO doesn't use the space (second paragraph of this page).  Nor does planet.iap.fr.  Nor does Nature.  Anville 13:28, 26 January 2006 (UTC)
replies: text: The Gliese 876 entry uses a space, so it's a Wikipedia convention at least. Of course, astronomical societies trump Wikipedia, but if there is no official standard or strong convention, it seems to be how exoplanets are written up in Wikipedia. If the space is wrong by "official" standards, other exoplanet articles might need repair. - Beowulf314159 13:40, 26 January 2006 (UTC)

text: Google search isn't useful here, yet. Searching Goodle for "OGLE-2005-BLG390Lb" only hit twice. Google hasn't spidered all the pages yet - it's only been announced for... 24? 36?.... hours. However, your assertion also holds true for the Google News search, for this exoplanet. Searching for "Gliese 876 d" and "Gliese 876d", Google search hits for both, although the non-spaced version hits twice as often. - Beowulf314159 14:00, 26 January 2006 (UTC)

text: I didn't realize the name of the star is the reason if there's a space or not.  If the name was going to be OGLE-05-390Lb since the star was named, i'll leave it bee.  But if the name was and still is obtianal, i'll be back. — Hurricane Devon ( Talk ) 18:03, 26 January 2006 (UTC)
replies: text: I said rules-of-thumb, not definitive guidelines. But the case here seems to be that the space you are insisting on is actually not used. Give us a source which uses the space. Otherwise, by inserting a space, you've invented a designation. Chaos syndrome 18:14, 26 January 2006 (UTC)

text: Besides - one of the discovery team has said they do not use the space? Looks like that settles it. Check the pre-print article to make sure it's not someone "pulling a fast one" - but whichever the use in the pre-print article is, use that. addendum: the abstract of the pre-print article does not use that space. Seems to settle that, unless you want to argue the discovery team can't name it? - Beowulf314159 18:27, 26 January 2006 (UTC)
thread_title:  Page name 

message: These bits about this planet being the "most earthlike ... at the time of its discovery" are misleading.  It implies that a more "earthlike" planet has been found since, which, being that this planet was discovered all of yesterday, cannot possibly be the case.  Until a more "earthlike" planet is found, the text should simply read "the most earthlike planet discovered to date." -  Che Nuevara:  Join the Revolution 15:27, 26 January 2006 (UTC)
replies: text: and when that happens, you guarentee that you personally will come back and change the article? Or will it just go "stale" and be inaccurate then? "To date" is a relative term, depending on the time of reading. - Beowulf314159 15:32, 26 January 2006 (UTC)
replies: text:  How about "as of January 26th 2006 it was the most earthlike..." Galuple 18:30, 26 January 2006 (UTC)

text: I'm more worried about Wikipedia being inaccurate now than "then".  Vague and misleading text is inherently unencyclopedic and, given that people are constantly crawling Wikipedia for errors, such an error would probably fix itself rather quickly.  Being that I read the article the day after it was first posted, I was relatively quickly able to discern that this vague information was, in fact, still true.  But five years down the line, if no "more earthlike" planet has been found, text like "at the time of its discovery ..." would be a costly error.  Yes, I said error:  implied errors are just as unencyclopedic (and damaging to Wikipedia's credit) as blatant ones. -  Che Nuevara:  Join the Revolution 17:52, 28 January 2006 (UTC)

text: Also, there is already precedent on this issue.  See, for example, the where Sears Tower article says it is "the tallest office building in the United States", not that "It was at the time of its building"; the largest photographs in the world say what the "current claim" is, not what the claim was "at the time this photograph was printed".  Search around Wikipedia if you like -- that's the way it's done, and that's the way it makes sense.  What if that turns out to be the most earth-like planet we ever find?  Wikipedia is not a crystal ball ... -  Che Nuevara:  Join the Revolution 18:01, 28 January 2006 (UTC)

text: I did.  I wanted to respond anyway, since there is no such thing as a permanent "resolution" on Wikipedia. -  Che Nuevara:  Join the Revolution 00:24, 29 January 2006 (UTC)
thread_title:  "At the time of its discovery ..." 

message: Can someone provide a referance for the stars distance? I've seen it quoted as 20 thousand, 25 thousand, and 28 thousand light years (See  here as well). Someone changed it from 20 to 28 in this article. The external referance right beside it says 20, while the article for the star says 28.
A pretty minor quibble, but does anyone have a referance to solve the confusion? - Beowulf314159 16:02, 26 January 2006 (UTC)
replies: text: I would've thought that we should stick with the ESO/OGLE official number. In my opinion, that's much more reliable than whatever pages might've got it wrong... Ghent 18:37, 26 January 2006 (UTC)
thread_title:  Distance? 

message: I'm an author on the actual Nature paper, just a few points:
-You should reference the scientific paper itself, not just Nature's commentary/press release. A preprint (identical text and figures but lacking the Nature formatting and copyright restrictions) is at:
http://arxiv.org/abs/astro-ph/0601563
A reference to the PLANET home page is also a good idea - http://planet.iap.fr
-the PLANET/Robonet microlensing followup group made the planet discovery, not OGLE. OGLE find microlensing events themselves, around 1000 in 2005 alone. They didn't find the anomaly that indicated this one had a planet. The paper's authors include all of PLANET, all of Robonet, all of OGLE, and all of MOA. PLANET found the planetary anomaly, OGLE found the microlensing event itself, and both OGLE and MOA have one or two points that confirm the planetary anomaly, but wouldn't be useful on thier own without the PLANET/Robonet data. Two-thirds of the data defining the planetary anomaly itself was taken at Perth Observatory.
-The planet parameters are:
mass: 5.5 Me +5.5/-2.7
Orbital radius: 2.6 +1.5/-0.6 Astronomical units, a period of 10.4 years
Distance: 6.6 +/- 1.0 kpc - that works out to ~ 21500 light years, +/- 3300, with sources rounding differently
Coordinates: RA=17:54:19.2, Dec=-30:22:38 (J2000)
-The ratio between the mass of the planet and the mass of the star is known fairly precisely (7.6 +/- 0.7)*10^-5, along with the lensing properties for the star (which depend on both star mass and distance). The latter, combined with a model of stellar mass distribution along the line of sight, lets us work out that the star mass is most likely to be 0.22 solar masses, within a factor of two (which gives most of the uncertainty in the planet's mass). There's a 4% chance that the parent star is actually a white dwarf, and <1% that it's a neutron star or black hole. In a decade or two, new telescopes are likely to be able to resolve the lens and background (source) stars individually, and pin down a precise mass and stellar type, which will in turn pin down the planet's mass.
-The main reason for the fuss about this planet is not so much the fact that it's the smallest mass so far - dozens of previous discoveries have met that criteria, one by one. If you look at a plot of mass versus orbital radius for all previous discoveries (170, not 150), they all cluster in the high-mass, small-orbit corner, and because of the huge selection bias in the Radial Velocity technique, the smallest planets have the smallest orbits. The nearest contender, Gliese 876d, has a three DAY orbit, compared to 10 years. This new planet sits smack in the middle of the region of parameter space enclosed by all the planets in our solar system - it would fit in perfectly, unlike any other planet discovered before.
A plot that shows this is at: http://www.wa.gov.au/perthobs/OB05390/KH-my%20mods.gif
-As well as the artists impressions - showing a generic icy planet - there are some raytraced lensing movies and stills showing the distortion caused by the gravity of the star and planet. This one shows the whole event, with the lens as a green dot, the true (undistorted) background star position and apparent size as a red circle, and the yellow images showing what you'd actually see from Earth over the 40-day lensing event. The planetary anomly is the short glitch in the primary image near the end of the movie: http://www.wa.gov.au/perthobs/OB05390/OB05390-whole.mpeg
The zoomed version shows just the anomaly, over two days: http://www.wa.gov.au/perthobs/OB05390/OB05390-zoom.mpeg
More info, movies, and images are at: http://www.wa.gov.au/perthobs/OB05390/
Andrew Williams
:Thank you!  Anville 19:07, 26 January 2006 (UTC)
thread_title:  Some corrections 

message: The orbit does not have an eccentricty. The +/- is a measurement and calcualtion error, not how much the orbit varies. Orbital elements are not known - Beowulf314159 01:20, 27 January 2006 (UTC)
thread_title:  Orbit Eccentricity 

message: Some time ago, the article said it was in the constelation of Sagittarius. Now it says Scorpius. Is this an error corrected or vandalism (or something else)? algumacoisaqq 20:43, 27 January 2006 (UTC)
replies: text: I think it's a correction. The person who made the change also made and uploaded the starmap using planaterium software, so I assume it's correct. You could download the starmap and check. - Beowulf314159 20:45, 27 January 2006 (UTC)
replies: text: "You could download the starmap and check" errr... i think I'll believe you... I had trouble figuring out the star was OGLE-2005-BLG-390L... algumacoisaqq 00:20, 28 January 2006 (UTC)

text: No. And since you also took an external reference out of the article, leave that alone too. You may find it personally "annoying" to have an external link in the opening paragraph, but you don't take references out of an article - even if you find them annoying. As for the talk page, learn to sign your comments. - Beowulf314159 01:30, 30 January 2006 (UTC)

text: I believe it's general practice to avoid footnotes, external hyperlinks or other inline citations within the lead paragraph(s) of an article.  Generally speaking, all points raised in the lead section should be developed more fully below, and it is in the sections below where one places the various forms of inline referencing.  This doesn't have the force of policy, of course, but lots of people like it this way (myself included).  I would also support modifying the statement about the constellation, though I'm not sure the best way to do so without verbal gymnastics.  Sounding like a bunch of astrologers is bad, but so is writing horribly awkward and convoluted prose.  Anville 15:55, 30 January 2006 (UTC)
thread_title:  Constellation 

message: Do people just smack copyright violation stickers on things without reading three days of history and discussion? - Beowulf314159 03:14, 29 January 2006 (UTC)
thread_title:  What the HELL? 

message: Will this planet be named? I don't mean something like the current name, I mean a name like the names of the planets Venus, Mars, Pluto, Saturn, etc, etc. --Revolución (talk) 03:29, 29 January 2006 (UTC)
replies: text: I don't think anyone knows. It's possible that it might be named after some famous astronomer, or something like that - just to commemorate them by naming something after them. However, unless they do something like that, it's unlikely it will be named anything other than it's catalog name. We will most likely never observe the planet directly - and it seems unlikely we'll even detect it again; planetary microlensing events are unique. So there's no real need - Beowulf314159 03:34, 29 January 2006 (UTC)
thread_title:  Name 

message: The only planet symbols that are in common use in astronomical literature seem to be the sun and the earth (interestingly, whoever put these symbols in seems to have used Mars instead of Earth and the usual Earth symbol is a circle with a plus sign in the middle). MJ seems to be fairly common. Is there a Wikipedia convention here? Not sure the Unicode symbols work on all computers either. Chaos syndrome 13:11, 29 January 2006 (UTC)
thread_title:  Unicode planet symbols