Talk:2018 VG18

Farout, bold?

The name of the article should probably be Farout, which is now and probably will end up to be its long-term common name. Randy Kryn (talk) 20:54, 17 December 2018 (UTC)

The articles for Drac and Niku use the 'licence plate' name.Agmartin (talk) 21:39, 17 December 2018 (UTC)

As per this. Farout is only just a nickname. It will in no way become the official permanent name. For example, 2003 EL61's name was "Santa", but due to IAU naming rules, now it's called Haumea. ― Дрейгорич / Dreigorich Talk 08:13, 18 December 2018 (UTC)

A redirect, as it is done now, seems to be the appropriate solution here. The principal name is 2018 VG₁₈. Renerpho (talk) 14:00, 18 December 2018 (UTC)

Should the nickname be bold, or not? 2014 MU69 does it; 2018 VG₁₈ doesn't. I don't see the difference, so this seems inconsistent.Renerpho (talk) 21:47, 25 December 2018 (UTC)

If the nickname redirects to this article, its first use can be bold in this article (as target of redirect). Absence of redirect does not, AFAIK, forbid the use of Bold. - Rod57 (talk) 12:16, 27 December 2018 (UTC)

The section MOS:BOLDLEAD provides guidance; a formal or widely accepted name is in bold if there is a redirect to the article. Hadron137 (talk) 18:05, 27 December 2018 (UTC)

I was wondering about the recent edits. I understand it now. Thanks!Renerpho (talk) 23:06, 27 December 2018 (UTC)

Discoverers

The text reads "[…] its official discoverers have not been determined." Yet we know who discovered and reported it, as shown in the infobox, so it looks like a contradiction, or a clarification is needed. Cheers, Rowan Forest (talk) 15:05, 18 December 2018 (UTC)

I think this has to do with a similar situation to Haumea, where the discover is known, but officially left blank due to a dispute. So the "official" discoverer and the one who actually discovered it may be different. Once the object has been named numbered, usually the discoverer is acknowledged as the official one, except in weird cases like this one. ― Дрейгорич / Dreigorich Talk 17:22, 18 December 2018 (UTC)

I haven't seen that in the articles I've read, perhaps the official discoverers would be different it was observed previously and lost, which can't be determined until after its orbit is better known. I recommend that the quoted part be dropped, the article can always be corrected later if the 2018 VG18 was precovered. Agmartin (talk) 17:41, 18 December 2018 (UTC)

Makes sense. Either way, it takes a while to know the discoverer. ― Дрейгорич / Dreigorich Talk 17:44, 18 December 2018 (UTC)

Went ahead and deleted. ― Дрейгорич / Dreigorich Talk 17:45, 18 December 2018 (UTC)

As with all minor planets, the official discoverer is determined when the object gets numbered, which has not happened yet. See the statement at the beginning of [1]. We know who took the first known observations, but that is not the same thing. Compare similar statements in other Wikipedia articles, like 2001 QR₃₂₂. I think the sentence should be added back again, maybe together with a clarifying sentence if necessary. Renerpho (talk) 23:59, 19 December 2018 (UTC)

Let me add: Determining the discoverer is more complicated than it may sound. It is not only a question of who's observations take precedence, but also which individuals among a team. For instance, is 2018 VG18 discovered by S. S. Sheppard? Or by S.S. Sheppard, D. J. Tholen, C. A. Trujillo? Or by the name of the site, Mauna Kea? All of these have actually been realised for objects found by those observers in the past. Right now, the article claims that the object was discovered by "Scott S. Sheppard, David Tholen and Chad Trujillo". That is true in an informal way, and is likely what will one day become official; but it is not official yet. Renerpho (talk) 00:17, 20 December 2018 (UTC)

I've reinserted the statement. ― Дрейгорич / Dreigorich Talk 06:36, 20 December 2018 (UTC)

Thanks! By the way, the Minor Planet Center maintains a preliminary list of potential discoverers for unnumbered Trans-Neptunian objects, see here and here. 2018 VG₁₈ should be added to the first of these in the next update. Incidentally, that list gives S. S. Sheppard as the discoverer of 2015 TG387, not D. J. Tholen, S. S. Sheppard, C. Trujillo as one might expect (and as is claimed in the corresponding Wikipedia article). That is not to say that this is what will become official when 2015 TG₃₈₇ is numbered... As said: The decision is made upon numbering. Renerpho (talk) 09:23, 20 December 2018 (UTC)

There is no doubt who discovered the object and there is absolutely no benefit in implying that there is a doubt or a conflict. The clerical minutia regarding the "registration process" is something else of no concern to this article. Just common sense, OK? Cheers, Rowan Forest (talk) 13:35, 20 December 2018 (UTC)

gravity

gravity should be about 0.4 m/s² — Preceding unsigned comment added by 2.247.255.151 (talk) 02:35, 19 December 2018 (UTC)

Source? ― Дрейгорич / Dreigorich Talk 23:12, 19 December 2018 (UTC)

Distance uncertainty

@Exoplanetaryscience: In the latest edit, a figure for the distance was added that includes a formal 1-sigma uncertainty, 125±29 AU.

While that is the correct formal uncertainty, there might be two problems here:
1. The source cited does not actually give that information, and
2. The actual uncertainty is much lower under the assumption that the orbit is "reasonable" (i.e., gravitationally bound to the Sun, and hence a Solar System object).

Since the uncertainty interval (94-154 AU) overlaps with the current distance of Eris (96 AU), a reader of the article may come to the conclusion that there is doubt whether the object is actually the most distant Solar System object. Such a doubt does not exist: Either the object is a Solar System object, in which case the distance is 101-144 AU (that figure is based on my own calculations), and hence definitely further out than Eris; or it is closer than 101 AU, in which case it is not a Solar System object because it can't be gravitationally bound to the Sun.

My proposal: To solve problem 1, add a proper source: In JPL Horizons, choose the settings

• Ephemeris Type [change] : VECTORS
• Target Body [change] : Asteroid (2018 VG18)
• Coordinate Origin [change] : Sun (body center) [500@10]
• Time Span [change] : Start=2018-12-22, Stop=2018-12-23, Step=1 d
• Table Settings [change] : quantities code=1r (Type 1, with RTN uncertainties)

The search result will be

• XYZ  : 3.622429310226449E+01 1.197023077719259E+02 -7.703080911510864E+00
• RTN(1-sigma): 2.88780196E+01

From which one can conclude that the uncertainty is indeed 28.9 AU, and distance ${\sqrt {X^{2}+Y^{2}+Z^{2}}}=125.3$ AU.

To solve problem 2, I suggest to add a note that explains why the formal uncertainty is not very useful in this case. Renerpho (talk) 05:28, 22 December 2018 (UTC)

Hmm, I didn't consider that the uncertainty was simply formal, even with it being unusually high. I'd mostly added it because the MPC is unnecessarily confident in the heliocentric distance of 2018 VG18, when it could in theory be as low as about 115 AU or as high as ~140 if my math is right. I suppose I'll clarify the point. exoplanetaryscience (talk) 20:35, 22 December 2018 (UTC)

Thank you! Hopefully, the object will be reobserved once the full Moon is gone. Extending the arc by just a few weeks will do wonders. We won't get a good estimate for its perihelion distance yet (that really needs at least a year), but we will formally know if it is in a highly eccentric (unbound) orbit or not. The MPC estimate (125-130 AU) is indeed overly optimistic. Depending on what weights you assign to the observations, the possible distance range is tens of AU. Renerpho (talk) 21:09, 22 December 2018 (UTC)

Yeah, hopefully there will be some followup observations soon, which there probably will judging by what I've heard from friends. Once we get an arc to around january or february, the uncertainty will be low enough that I can constrain its size by seeing if it's visible in WISE images. exoplanetaryscience (talk) 22:17, 22 December 2018 (UTC)

I didn't think about WISE yet. Probably worth checking... Bill Gray has put online a "toy model" of 2018 VG₁₈, with observations between now and 2022 to simulate the expected evolution of the orbit uncertainty (he uses a fictitious orbit, with the object currently at aphelion).[2] Judging from that, with an rms of 0.137" for the real data,[3] extending the arc to February 2019 should give us an uncertainty of the order of an arcminute in 2010, maybe enough to find it in the earliest WISE data if it's there. Please keep in mind that, at such an uncertainty, you still need to demonstrate motion in the WISE data to make sure that what you see is not a background source. If you want to be sure, wait for David Tholen's work on the 2015 and 2017 precoveries; that will get the 2010 uncertainty down to less than an arcsecond, telling you exactly what pixel to look at in the WISE images.Renerpho (talk) 22:20, 25 December 2018 (UTC)

Symmetrical uncertainty bounds look strange

In the info box the symmetrical bounds on the orbital parameters look strange (since they are larger than the nominal value) - Why not use just the two 1-sigma bounds instead to show the most probably range ? - Rod57 (talk) 12:22, 27 December 2018 (UTC)

The source [4] only gives symmetric uncertainties. Of course, the uncertainty intervals are highly asymmetric, so those uncertainties are only formally correct! The text mentions that the orbit is completely unconstrained, apart from the large distance, which is another way to say that the uncertainties are much larger than the nominal values. If you have a source that gives 1-sigma bounds in positive and negative directions separately, please let me know. Showing a "most probable range" is hardly possible in this case: Because this is the first object found at such distance, there's no a-priori statistic that could help you. Of course you could say that e is most likely between 0 and 1 (but the data could fit an orbit with e=20 as well), and q is definitely between 0 and 125 AU, or between 7 and 122 AU if you assume an orbit that is gravitationally bound to the Sun, and likely around 30-40 AU if the object is like other SDOs; that i is between 10 and 70 degrees, and likely between 15 and 35; and that a is most likely positive. But what does that help, and do you have a source other than my/your own calculations? This problem will resolve itself within a few weeks, as more observations will pin down the orbit considerably in January or February. Renerpho (talk) 18:02, 27 December 2018 (UTC)

Side note: This is why TNOs don't usually get announced within a month after discovery (2018 VG18 is a rare exception). No TNO has a useful orbit within a month, it needs at least a year of data to draw conclusions.Renerpho (talk) 18:04, 27 December 2018 (UTC)

To be fair, 2018 VG18 is an extreme example of a bad solution with a 1-month arc, due to its extremely slow motion. Take something like 2014 GB54, which has a pretty well-constrained orbit for an observation arc of only 47 days. I agree that 2018 VG18 was announced a bit prematurely, but the fact that many other objects are announced 3+ years after their discovery is just overkill. exoplanetaryscience (talk) 02:08, 28 December 2018 (UTC)

2014 GB54 is an interesting example that shows the striking difference between an arc of 4 weeks, and an arc of 7 weeks. If you only use the first 8 observations (2014 Apr 4-29), you get an arc of 25 days, not far from that of 2018 VG18. Calculating an orbit from that gives you formal uncertainties of q=8.9±40.6 AU, e=266±2861, i=163±60°. Even more crazy than what we have for 2018 VG18. It's true that the slow motion (large distance) of 2018 VG18 makes orbit determination more difficult than usual, but even at a distance of 29 AU like 2014 GB54, a 1-month arc can be meaningless.Renerpho (talk) 03:10, 28 December 2018 (UTC)

I don't know why 2018 VG18 was announced now, rather than 1-2 months later when its orbit will likely be pinned down (maybe up to some uncertainty in the eccentricity if the orbit is near-parabolic). It becomes even more baffling when you consider that exciting orbits, like high-perihelion sednoids, a circular orbit at 120 AU, or even an interstellar object, are not ruled out yet (even though they are not likely). If it turns out to be one of these then the team will have missed an opportunity to gain some serious media attention. Making a 2nd press release about 2018 VG18 is potentially less effective. Renerpho (talk) 03:34, 28 December 2018 (UTC)

I see the press release as a repeat of the one for V774104. Reporting it to MPC now instead of waiting should avoid later confusion about which object it is. Agmartin (talk) 16:29, 28 December 2018 (UTC)

Maybe they try to learn from that previous mistake, yes. One thing I'd like to add (for the protocol): In case anyone is unclear about this, 2018 VG18 has no chance of being the object announced in 2015 as V774104.Renerpho (talk) 02:29, 29 December 2018 (UTC)

Italics and Farout

I'd removed the italics from Farout and that was reverted by Дрейгорич because "not an official name". I don't know what adding italics has to do with making it obvious it's not an official name, that just makes it incorrectly italicized. Am I missing something? Thanks. Randy Kryn (talk) 15:37, 28 December 2018 (UTC)

Nicknames of objects given by the discoverers are usually only used by the discoverers themselves, the media, and the public at large. They are not what the object is officially referred to as in scientific publications or by the IAU and JPL themselves. The IAU and JPL's databases of known asteroids would not list the object under "Farout", and only list it as "2018 VG18". ― Дрейгорич / Dreigorich Talk 15:39, 28 December 2018 (UTC)

(edit conflict) I appreciate that Дрейгорич is trying to make the article as precise as possible, being a scientific subject and all, but I reverted him before I saw this post. I agree with Randy, in that I find the italics more confusing than their absence, and in fact italics seem to suggest an official title. I can't find any indication italics should be used per WP:ITAL. 78.26 _{(spin me / revolutions)} 15:43, 28 December 2018 (UTC)

(post edit-conflict) I don't think anyone disagrees with the facts presented directly above by Дрейгорич. However, I don't think adding italics is the proper way to convey those facts. 78.26 _{(spin me / revolutions)} 15:43, 28 December 2018 (UTC)

My point is that unitalicizing the nickname might lead to uninformed readers to assume that "Farout" is the actual proposed name for the object or the actual name of the object other than an unofficial nickname. See Valetudo (moon) especially in the early stages. The article was created at Valetudo (moon), changed to S/2016 J 2 when it was realized Valetudo was an unofficial nickname used by the discoverers (the name Valetudo was mentioned in the article) and after the moon was officially named Valetudo by the IAU, the lead was changed to mention Valetudo as the primary name. ― Дрейгорич / Dreigorich Talk 15:47, 28 December 2018 (UTC)

This edit from the S/2016 J 2 days: https://en.wikipedia.org/w/index.php?title=Valetudo_(moon)&diff=next&oldid=850707239 — Preceding unsigned comment added by Дрейгорич (talk • contribs) 15:50, 28 December 2018 (UTC)

Since the wording is "nicknamed Farout" the meaning should be clear to readers, and if not then they should be nicknamed Farout and go about their business. But as 78.26 (a user name that educates) points out, italics don't convey unoffialness to something. The word 'nickname' should be enough, while italics would imply it's either an artwork or a spaceship and further confuse the readers who missed the word 'nicknamed'. Randy Kryn (talk) 15:53, 28 December 2018 (UTC)

Sigh... very well then. We'll have it your way. I would encourage rewriting the lead to not put the nickname in the first sentence though, but whatever you wish. ― Дрейгорич / Dreigorich Talk 15:57, 28 December 2018 (UTC)

Not my way, just the styling for this. I don't have proof, but the nickname is probably the common name at present and, unless the official name turns out to be better and more interesting (i.e. a doozy), will be the common name in the future. So its placement as an alternate name of the article title seems consistent with other pages. Randy Kryn (talk) 16:14, 28 December 2018 (UTC)

Yeah, true. Once the media hype is over though, it will be the scientists doing all of the work on it. And once it gets named, Farout will be forgotten except in the history books. ― Дрейгорич / Dreigorich Talk 16:18, 28 December 2018 (UTC)

No italics, and not mentioned in the first sentence but somewhere in the introduction. The use of bolding is fine, as it is the common name -at least for now. Rowan Forest (talk) 19:09, 28 December 2018 (UTC)

The nickname should be bolded, not in italics. Farout redirects to this article and it's a name in common use. Jonathunder (talk) 19:33, 28 December 2018 (UTC)

Farfarout?

New object: https://www.sciencemag.org/news/2019/02/astronomers-discover-solar-system-s-most-distant-object-nicknamed-farfarout No official designation yet. Any info? Ardenau4 (talk) 19:10, 23 February 2019 (UTC)

Farfarout gets a brief mention in the second paragraph of this article. But all the info I have seen says that farfarout was just discovered and that it is estimated to be 140 AU (21 billion km) from the Sun. It still needs to be confimed with follow-up observations. The error bars are probably pretty big. - Kheider (talk) 19:28, 23 February 2019 (UTC)

While looking for Farfarout at the MPC I noticed that 2018 VO35 and 2018 VM35 have updated 88 day orbits but not 2018 VG18. Agmartin (talk) 19:50, 23 February 2019 (UTC)

Object 2014 FE₇₂

Why is 2014 FE72 not a scattered disc object? It seems to meet all the specifications of the definition. WolfmanSF (talk) 21:36, 20 January 2020 (UTC)

I'm not really sure about its classification, as it varies depending on the source. Buie's website states it is a centaur, the Minor Planet Center classifies as a scattered-disc object, and Scott Sheppard classifies it as an outer Oort cloud object in this paper. Should there be a consensus on 2014 FE72's classification or does it not matter? Nrco0e (talk · contribs) 22:29, 20 January 2020 (UTC)

Scott Sheppard's classification is not consistent with our definition of the inner Oort cloud, which extends to 20,000 to 30,000 AU. Marc Buie's classification is not consistent with our definition of a centaur, which entails a perihelion less than Neptune's (29.8 AU). I would consider the MPC classification as being more authoritative, and since it is also consistent with our definitions I think we should go with it. WolfmanSF (talk) 22:44, 20 January 2020 (UTC)

Ambiguous/conflicting/contradictory orbital period?

Feel out if my depth here as sounds like most here are astrophysicists and astronomers. Seems to me the ± value is too large. If subtracting from the previous/initial value you would end up with an orbital period of negative years. Should comma be a period? Or do I not understand the notation? Quisizyx (talk) 21:17, 16 March 2020 (UTC)

@Quiszyx: The uncertainty of the orbital parameters are taken directly from JPL Small-Body Database Browser page. Currently, 2018 VG₁₈'s orbit is largely uncertain and varies by source, such as the Minor Planet Center's page. Nrco0e (talk · contribs) 02:52, 17 March 2020 (UTC)

@Quiszyx: This is a common occurance for objects with very uncertain orbits. It partly comes down to the fact that eccentricities larger than 1 cannot be ruled out yet with confidence. That is, we cannot rule out hyperbolic orbits for which the period is undefined. Having a period of 1223 ± 1400 years means that we can't tell if there exists a period at all. If this object has a period then that is of course positive and finite (per definition). We can be quite confident that it has a positive and finite period, as that's the most likely scenario, but the data for this object alone is not enough to tell. So, the ± value is not too large. It is just telling you that the value we have for the period is completely undetermined. It is important to stress that there are things we know about this object with much greater certainty. In particular, we know its distance to good accuracy (to ± a few AU), we know the orientation of its orbit, and we know how close it came to the Sun at its closest. We don't know yet where it's heading from there - more data is needed for this. The alternative for having a period would be that it is a hyperbolic asteroid, which is a very unlikely (basically impossible), but not completely impossible, scenario. Renerpho (talk) 06:35, 17 March 2020 (UTC)

The most extreme example that I am aware of is 1999 DP8, which has a period of 1246 ± 52310000 years.[5] What does that mean? It means we don't know its period at all.Renerpho (talk) 06:41, 17 March 2020 (UTC)

"First imaged" versus "earliest precovery"

The dates given in the infobox are confusing. It says that the object was discovered on 10 November 2018 (the date it was allegedly "first imaged"), and that the "earliest precovery date" is 16 January 2017. While 10 November 2018 will probably become the official discovery date once this object is numbered (following the usual procedures), it isn't the date of the first observation, and it isn't the date when the object was first noticed by a human. What is it? Renerpho (talk) 19:47, 30 December 2020 (UTC)

Nothing has been done about this in the last three years. I have now gone ahead and removed the "first imaged" part. Renerpho (talk) 12:13, 1 September 2023 (UTC)