User talk:Exoplanetaryscience/2018

Note that any non-free images not used in any articles will be deleted after seven days, as described in section F5 of the criteria for speedy deletion. Thank you. --B-bot (talk) 17:47, 2 July 2018 (UTC)[reply]

Thanks for adding those moons. Can you also fix these?

https://en.wikipedia.org/wiki/Timeline_of_discovery_of_Solar_System_planets_and_their_moons https://en.wikipedia.org/wiki/List_of_natural_satellites

Thanks.

I'll try, but I can't guarantee I'll be quick with some scheduling problems. exoplanetaryscience (talk) 17:31, 17 July 2018 (UTC)[reply]

S/2003 J 9, 16, and 23 are no longer considered lost. They are listed as L?? in https://sites.google.com/carnegiescience.edu/sheppard/moons/jupitermoons.

Large does not equate to notability. As the footer says on all the country and region lists, effects are what define notability. Please restrict yourself to the yearly lists. Unlike the country/region lists, WP:Earthquakes has not gained control over those yet. Thank you, Dawnseeker2000 22:45, 21 August 2018 (UTC)[reply]

About ten years ago a user requested and moved several cometary articles from their official designation to their "common name", for example:

• 9P/Tempel
  )
• 17P/Holmes
  )

In addition, articles of some low-numbered comets such as:

• Halley's Comet
• Comet Encke
• Biela's Comet

do not use their official designation in their title as well.

I'm in favor to consistently rename all these cometary articles to their official designation as shown in List of numbered comets § List. The lead sentence, as currently the case, may still mention the common name before the official designation, for example

• Halley's Comet or Comet Halley, officially designated 1P/Halley...

You've been editing these articles for a long time. What's your take on this? Rfassbind – talk 12:56, 12 October 2018 (UTC)[reply]

Hi @Rfassbind: sorry for the slow reply. Personally, while I support some being named their proper names, I think some should keep their official designation. I think it should fall down to the way we resolve a lot of other astronomical objects: look up mentions in google searches & in literature and see if one is particularly favored over the other. For instance, Tempel 1 gets 302,000 results in google, while 9P/Tempel gets only 39,500. Comet Holmes gets 31,400 results while 17P/Holmes gets 47,400, possibly calling for a rename. For what it's worth, I'd also appreciate if Pallas, Vesta, and Sedna were renamed to non-numbered designations as well due to their names being so well-known compared to anything else of the same name. exoplanetaryscience (talk) 20:19, 13 October 2018 (UTC)[reply]

Thanks for explaining your view. So you are actually in favor to name more cometary (and other) articles by their "common" name. Did you check

Comet Biela, latter which gets a lot more hits on google than former? It's nice to have rules, but shouldn't they be followed as well? Two of the five "random" examples above do not comply with the google-ranking. And if these rules are not followed, is it, maybe, because they are not feasible? Rfassbind – talk 23:26, 13 October 2018 (UTC)[reply

]

I don't see why the fact that they're not currently followed means they're not feasible. For a few of the comets (such as Comet Holmes) the number of results is relatively similar, so not only would people be somewhat split on what name they commonly use for it, but the exact designation to use would be up for debate. Really, I just think it should be a guideline if the generally accepted naming isn't clear. exoplanetaryscience (talk) 00:34, 14 October 2018 (UTC)[reply]

Thx for your insight. Best, Rfassbind – talk 22:54, 14 October 2018 (UTC)[reply]

Hi EpS, very much appreciate all that you're doing on the pages I view and contribute to, not to mention the ones I don't look at myself. There has been an edit to the Asteroid impact prediction page recently which improves the precision of the text but loses accuracy. I don't want to just remove the edit and get into an edit war, and I can't contact the user who did it as they were anonymous. It would be good to hear any thoughts you have. Old text:

However current telescopes are not powerful enough to detect the smaller asteroids that commonly impact Earth unless conditions are just right, which is why so few are detected

New text:

However current telescopes do not monitor the sky often enough to detect most of the smaller asteroids that commonly impact Earth during the short time that they are bright enough, which is why so few are detected.

The problem is of course that there are a large number of contributing factors, not just that "current telescopes do not monitor the sky often enough". In particular, between now and impact in x years, an asteroid may never be bright enough to be detected by current telescopes. Indeed if it's an Aten asteroid it might never be in opposition prior to impact. Apart from the phase angle, there is also the question of where in the celestial sphere the asteroid is - it may be bright enough but only in a part of the sky that can't be viewed by the telescopes that could detect it. Finally of course, regardless of these factors, it isn't possible to see any asteroid on final approach if it's approaching from inside our orbit because the sky is in the way! I do take on board their point that it's not just about how powerful telescopes are, which is the way my original wording may have made it sound, but this is the introduction of the article so we probably don't want to go into too much detail here, hence my get out "unless conditions are just right". That does sound rather woolly though! Do you have any suggestions for a rewording here, and would you be happy to make the edit to avoid the danger of an edit war? Or do you think it's safe if I just go ahead and fix it myself?

Thanks in advance for your time and your thoughts.

Rafflesgluft (talk) 14:32, 13 October 2018 (UTC)[reply]

Hmm, that's a tough one. I feel like the optimal way to phrase it would be somewhat in between those two. Here's an example sentence that I think would work:

However, current telescopes are only capable of detecting a small fraction of asteroids that commonly impact Earth due to the short time that they're bright enough to detect, as well as the fact that many approach Earth from within its orbit at solar elongations too low to be detectable through the Sun's glare.

How does that sound? exoplanetaryscience (talk) 20:29, 13 October 2018 (UTC)[reply]

Good stuff! If you're happy to put that in, I'd very much appreciate it. Thanks for your other edits on the page by the way. Regarding A106fgF and uncertainty of impact, my thought when creating the "List of successfully predicted asteroid impacts" section was to be binary about it and include all objects with >50% chance of impact (both past and future), i.e. more likely than not. Perhaps if we include lower probability objects such as A106fgF, a useful extra column to have would be probability of impact. We could then also include 2010 RF12 (predicted 5% chance of impact in 2095 from 3 day obs arc) and possibly even 2006 JY26 (predicted 0.7% chance of impact from 4 day obs arc)? Rafflesgluft (talk) 08:00, 15 October 2018 (UTC)[reply]

On that page, I think that there's an important distinction to be made here. Those objects like 2010 RF12 are long-term predicted objects. They're things that we are, at some point, going to be able to prove for certain will/won't impact Earth. A106fgF is a relatively rare case that has only turned up once so far in the last few years of advanced asteroid approach detection, where even after its "impact" we still don't know for certain what its fate was. I do think it could be reasonable to include decent-probability objects like 2010 RF12, but if you start putting the list to objects with a low chance of impacting Earth in the future, you're going to quickly end up just copying the sentry risk table over onto the page. exoplanetaryscience (talk) 08:24, 15 October 2018 (UTC)[reply]

Hmm yes OK, certainly don't want to fill the table with a duplicate of Sentry. OK let's stick with the 50% probability filter for future impactors. On a tangent here, there is a lot of stuff that needs adding to the page, but your A106fgF note has made me wonder - is ATLAS the only dedicated asteroid impact prediction system in the world? If so it should definitely get a section on the page! I'm happy to add it (will just grab some of the text and refs from the main article and add a "see main" at the top of the section)... but being fairly new here, I'm not sure if it's true that it's the only dedicated asteroid impact prediction system (what I mean is telescopes like PanSTARRS and LSST have other goals too, whereas ATLAS, although it does spot e.g. supernovae as a side effect, is designed from the ground up at finding NEOs). Hope you don't mind the tangent. Can you confirm/deny (even better do you have a reference)? Thanks Rafflesgluft (talk) 12:34, 15 October 2018 (UTC)[reply]

Honestly, while I think ATLAS as far as I'm aware may be the only survey of that specific type, I don't think that's very significant. PANSTARRS was still done with an important primary goal of finding new asteroids (Something it's done quite successfully, at that), and while not NEO-focused, the mount lemmon survey and catalina sky survey have done a phenomenal job of that as well. then there's LINEAR and Spacewatch, which are somewhat debatable, though. Anyway, I'd say that the main thing ATLAS has on all of these is the fact that unlike most of those other surveys, ATLAS doesn't immediately disregard objects that appear to be moving unusually fast- don't quote me on this but it seems they tend to observe such objects long enough to determine whether they're Earth-orbiting or not before reporting them. If you're particularly interested in their survey methods, you could always ask them directly. When I realized I lost the observations of A106fgF to calculate the probability of impact, I emailed them about it and I was actually given the original discovery plates of the asteroid! exoplanetaryscience (talk) 06:42, 16 October 2018 (UTC)[reply]

Wow that's amazing! It's very reassuring that the people carrying out this work take the time to answer queries. I'll try to add a section about the main current surveys I think. Regarding not quoting you, I promise not to cite your talk page ;-) Rafflesgluft (talk) 07:17, 17 October 2018 (UTC)[reply]

Thanks for adding the other surveys. I've just added the Space Surveillance Telescope as although not currently active, it seems to only be due to poor planning, and was active for a few years. I don't know where you got the "Peak yearly observations" from, but do you have the figures for the Space Surveillance Telescope? It's observatory code is G45 if that helps. Thanks — Preceding unsigned comment added by Rafflesgluft (talk • contribs) 22:11, 20 October 2018 (UTC)[reply]

Alright, updated it. My source is this data page from the minor planet center on the accuracy of various observatories: https://minorplanetcenter.net/iau/special/residuals.txt Oh, and for the active years, considering a lot of these surveys go through sparse testing phases before their main observing period, I only included active years as when the amount of observations was within an order of magnitude of§ its maximum activity. exoplanetaryscience (talk) 01:41, 21 October 2018 (UTC)[reply]

Nice! Wow looks like it was pretty prolific too. One thing that surprised me about this telescope, it doesn't track the movement of the Sky so can only take very short exposures (2-3s) leading to a lack of depth. Still, it's clearly a huge asset. I really hope they can solve the engineering problems and get it up and running soon!Rafflesgluft (talk) 07:53, 22 October 2018 (UTC)[reply]

I saw this in the listings the other day. According to the Scout page:

Object Summary -- ZU836EC
Last Update (UTC)		2018-10-18 08:02
#obs					4
Arc (h)					0.40
RMS						0.24
H						16.6
Impact Rating			0
MOID (au)				0.05
CA Dist. (LD)	
Vinf (km/s)				62.6
PHA						44
NEO						86
NEO > 1km				57
Geo.					0
IEO						0
TJ < 3					61
Ephemeris Time (UTC)	2018-10-24 11:00
RA (hh:mm)				01:36
Dec. (deg.)				+04
Elong. (deg.)			171
Rate (″/min.)			0.9
V (mag)					20.6
POS Unc. (′)			11
POS Unc.+1 (′)			14

If that Vinf is correct then it's interstellar isn't it (or am I missing something)? I was just wondering if it is worth adding it to the Interstellar object page? It's a shame about the moon - I assume people would be watching this if it were possible!

No, it's not. The object's got an observation arc of all of 24 minutes, and I've never seen anything with a decent orbit that's been observed less than about 40 minutes (A106fgF is actually the record in that regard as far as I'm aware) exoplanetaryscience (talk) 09:00, 25 October 2018 (UTC)[reply]

OK thanks. So presumably the chances of somebody picking it up by the time the moon has waned are slim? What speed was A106fgF going at?Rafflesgluft (talk) 11:10, 25 October 2018 (UTC) EDIT: sorry just realised what you meant, A106fgF has the record in terms of observation arc being short and yet still providing a useful prediction, not the record in terms of Vinf. I do hope that it is possible for at least one more observation of ZU836EC before it's too faint - even if the estimate is out by a factor of 2 it's still moving very fast!Rafflesgluft (talk) 14:08, 25 October 2018 (UTC)[reply]

Yeah, probably should've been clearer about that. At any rate, ZU836EC won't end up getting followed up because the MPC removed it yesterday night. I doubt there was very high odds of it being too interesting anyway, 0.9 arcsec/min isn't really very fast at all. That's only about 50% faster than Ceres's apparent motion. Anything moving less than about 30 arcmin/hr aka 30 arcsec/min has a veeeerry low chance of passing less than 1 LD from Earth. That said, we were able to tell A106fgF passed close to Earth because when it was found, it was moving at 21 arcmin/hr, and by the last observation only 40 minutes later it was already moving at 22 arcmin/hr. exoplanetaryscience (talk) 19:45, 25 October 2018 (UTC)[reply]

Thanks, and no problem, I also was unclear. I wasn't referring the apparent motion but its velocity. 62 km/s far exceeds solar escape velocity from Earth orbit (42 km/s)... which would make it completely uninteresting from an impacting earth point of view, as it will never come back, but very interesting from the

Oumuamua is currently the only confirmed instance of such an object. Rafflesgluft (talk) 10:53, 26 October 2018 (UTC)[reply

]

Yeah, although the angular movement and vinf can be connected. 1I/2017 U1 is indeed both the only suspected and confirmed instance of an interstellar object- although it should be noted that we have made a handful of detections of interstellar meteoroids, none larger than about 10-20 centimeters or so I think. exoplanetaryscience (talk) 22:15, 26 October 2018 (UTC)[reply]

OK. Now I see what you mean about the lack of accuracy in orbit parameters from such a small arc. I just checked PP and it turns out there have been further observations of ZU836EC, and looks like it is a plain old main belter. Thanks for taking the time to respond by the way. Much appreciated Rafflesgluft (talk) 19:12, 29 October 2018 (UTC)[reply]

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Hi there, revising the list in minor-planet moon for Jupiter trojans, a came across your edit from 27 October 2016 where you added a number of binaries without providing a source (they are not listed at Johnston's Archive). I have out-commented these entries for now. Best, Rfassbind – talk 17:21, 11 December 2018 (UTC)[reply]

@Rfassbind: hey, really sorry about the (very long) delay. That was based on some Kepler paper (I believe) that studied jupiter trojans in the field and found a handful with unusually long rotation periods, which they proposed might be candidate binary systems. Feel free to remove them if you want, as it's far from confirmed. exoplanetaryscience (talk) 05:51, 21 December 2018 (UTC)[reply]

Thx for the reply. There is no hurry on my part. I think it's best to stick to the list provided by Johnston's Archive (main source) which includes both, probable candidates and confirmed binaries. Let's keep the outcommented part for now and see if any K2 results will also show up in Johnston's archive one day. Rfassbind – talk 08:33, 21 December 2018 (UTC)[reply]

Hi Eps. Apologies for not updating so much recently, I've got busy! In the meantime I've been wondering what the secret ingredient is that those Catalina guys put into their surveys that makes them so potent. Here are the stats based on 2018 confirmed asteroids under 1 LD (confirmed asteroids only because web archives are blocked to me):

Mt Lemmon : 34
Other CSS : 21
ATLAS     :  9
ZTF       :  8
Pan-STARRS:  1
JAXA SSS  :  1
Amateur   :  1

The fact that CSS dominates the numbers is borne out in the graphs you see that don't limit it to 1LD, like this: [3]

The question is, what makes them so much more productive than the rest? Both the 0.7m CSS and the 1.5m Mt Lemmon are wiping the floor with everyone else (including Pan-STARRS - any idea what happened to them this year)?

Pan-STARRS and Spacewatch both have 1.8m primary mirrors, so that can't be it, especially as the CSS 0.7m scope is doing so well. They both survey the sky relatively slowly, so it can't be that they're getting to scan the relevant bit of sky before other surveys get a chance. They are relatively high at 2.8 km up, but the 1.2m ZTF is 1.7 km up and in the same region, and (claims to) scan much faster and to greater depth than the CSS 0.7m so you'd expect it to be more effective, but it isn't. What am I missing? --Rafflesgluft (talk) 21:09, 19 December 2018 (UTC)[reply]

To be completely honest, no idea. I've seen some of the images CSS uses in their asteroid hunting and honesty they're nothing miraculous. It could be that they've simply got better asteroid detection programming. It's definitely an interesting trend that I'm surprised I didn't consider much. BTW as for the unconfirmed asteriods, here's the stats for those, which you'll find don't differ much, although I suppose CSS has a bit lower hold on that. Maybe they're just as prolific as the other surveys, but since the asteroids they discover are brighter, they have a higher chance of getting properly followed up to confirm their proximity?

ATLAS    :  4
Mt Lemmon:  4
CSS      :  3
ZTF      :  1

exoplanetaryscience (talk) 22:17, 19 December 2018 (UTC)[reply]

OK thanks. Interesting to see that ATLAS' unconfirmed count is a high proportion of its total discoveries. I guess that's because it tracks the fast moving ones, which makes follow up less likely. I did a bit of digging and apart from a fairly nebulous statement on the CSS site, which does cast some light ("discovery rates are ever-increasing with improved hardware, cameras, computing capabilities, processing speeds, and detection algorithms" https://catalina.lpl.arizona.edu/science/discovery-statistics), the main clue I found was budgets. E.g. this page (which badly underestimates the LSST cost), puts the build budgets for CSS and Pan-STARRS at around $100 million ballpark. In contrast we know that the ATLAS budget was only $5m and that included everything needed for the first 5 years of operation. So it appears the secret ingredient is cash, which annoys me, but I suppose I shouldn't be surprised. I wonder if the larger amount of money gets you adaptive optics or something, that perhaps ATLAS (and ZTF?) can't afford. Whatever they spend the money on it seems to be working though! --Rafflesgluft (talk) 21:46, 20 December 2018 (UTC)[reply]

Pan-STARRS are not looking for fast-moving objects, hence why Catalina and ATLAS are much more effective at finding objects close to Earth than Pan-STARRS is. Pan-STARRS is optimized for finding objects while they are still far out, down to limiting magnitude 22 and fainter, which means they tend to find larger objects with smaller chance to make very close approaches. Catalina and ATLAS, on the other hand, do not have the limiting magnitude to allow such a strategy, and they concentrate on finding objects that are closer, with larger fields of view and somewhat brighter limiting magnitudes of about 20. Consequently, Catalina and ATLAS are overrepresented in the statistic of asteroids that made very close approaches to Earth. It is no coincidence that all three impacting asteroids (2008 TC3, 2014 AA, 2018 LA) were found by Catalina, with an independent discovery of 2018 LA by ATLAS... The high percentage of ATLAS discoveries that don't get followed up has several reasons, one being that ATLAS is the only survey currently imaging down to far southern declinations. Catalina can always rely on follow-up, while many ATLAS objects are too far south for most observers to track. That problem should be solved once ATLAS's new facility in South Africa comes online, so ATLAS can do its own follow-up.Renerpho (talk) 06:27, 22 December 2018 (UTC)[reply]

I proposed a merger of the two articles. Soon it might have to be moved to ...2019. I'd appreciate your input. ― Дрейгорич / Dreigorich Talk 21:11, 22 December 2018 (UTC)[reply]

I think that's a good idea. I just created that page because it would be strange to have it for 2015, but not include any other years. I fully support a merge and will give my comment on the proposal. exoplanetaryscience (talk) 21:50, 22 December 2018 (UTC)[reply]