Talk:2024 YR4

Lunar impact

Hi, I just added a Moon subsection on the impact effect section showing the probability with which the asteroid could hit the moon. Accuratelibrarian (talk) 17:02, 17 February 2025 (UTC)

@Accuratelibrarian: In [1] from February 10th, David Rankin quotes me on the possible visibility from Earth (And Rankin reports that his colleague, astronomer Daniel Bamberger at Northolt Branch Observatories in London said, “The impact could be brighter than the full moon. Safe to say it would be visible with the unaided eye.”). I'm not going to add it to the article, out of WP:COI concerns about citing myself; but if it's determined to fit, feel free to add it. Renerpho (talk) 19:16, 17 February 2025 (UTC)

Sure, the info you provide is valuable. I will also add the estimated diameter for the impact crater as well as the estimated impact velocity. Accuratelibrarian (talk) 19:56, 17 February 2025 (UTC)

Do you know if there is any impact corridor map for the Moon? Accuratelibrarian (talk) 20:45, 17 February 2025 (UTC)

@Accuratelibrarian: Yes, there is. Bill Gray (author of Find_Orb) computed one.[2] Renerpho (talk) 21:37, 17 February 2025 (UTC)

Thanks, I will reach out to him and ask him for permission to upload it. By the way, I don't see Mare Crisium on the map, is it beyond Mare Nectaris? Accuratelibrarian (talk) 21:56, 17 February 2025 (UTC)

Do you know the date for potential lunar impact? Accuratelibrarian (talk) 22:22, 17 February 2025 (UTC)

Same date as for an Earth impact (22 December 2025). The times are in the image.

Mare Crisium is way beyond Nectaris. You won't have trouble finding it on a map. Renerpho (talk) 01:28, 18 February 2025 (UTC)

Bill Gray has removed his lunar impact map (previously at [3]) from his website, possibly because he found it to be in error. Renerpho (talk) 17:17, 27 February 2025 (UTC)

I believe he said the timing was correct, but that the longitude could be off. Steven has similar timings.-- Kheider (talk) 17:27, 27 February 2025 (UTC)

A corrected version is now available at the same url ([4], with a list of coordinates for the virtual impacts at [5]). The issue was a flip in the longitudes of the impacts; compare the earlier version, which has been archived at [6]. Renerpho (talk) 16:14, 1 March 2025 (UTC)

I've tagged "An impact before 15:18 would be visible in the shaded part of the 70% waning gibbous moon." as dubious. This was based on Bill Gray's map. It was probably WP:SYNTH anyway, and is in contradiction to the new map. Are there any news accounts that have picked up this detail? If so then we have to be careful about WP:CITOGENESIS. Renerpho (talk) 16:19, 1 March 2025 (UTC)

Defense

This section could explore how the necessary cost and kinetic energy of a DART like kinetic impactor mission varies depending on when it is launched and makes impact, and a few of the scenarios explored. Even though they won't be needed for this impactor, I think this topic is very much encyclopedic. Discussion of how deflection mission parameters could vary hugely - the mass and speed and time between launch and deflection and predicted impact, in other words, Asteroid_impact_avoidance, as applied to 2024 YR4. — Preceding unsigned comment added by RememberOrwell (talk • contribs) 05:13, 27 February 2025 (UTC)

TDB vs UTC

Do we have a preference for Coordinated Universal Time (UTC) or Barycentric Dynamical Time (TDB) times in the article? The difference can be ~2 minutes when looking at the JPL SBDB vs the web interface for JPL Horizons. For example, JPL SBDB #69 shows closest approach to the Moon at 15:04 where as Horizons is showing it at 15:02. Does TDB invoke too much wp:jargon for the casual reader? Is it best to leave TDB for the footnotes? -- Kheider (talk) 19:10, 2 March 2025 (UTC)

I generally prefer to give times in UTC. Renerpho (talk) 23:57, 2 March 2025 (UTC)

Why is there such a large difference? Shouldn't TDB be close to TT, which should only be about 70 seconds from UTC? Patallurgist (talk) 01:22, 4 March 2025 (UTC)

Looking at the sources, I guess 15:02:27 plus 69 seconds rounds up to 15:04. Patallurgist (talk) 01:29, 4 March 2025 (UTC)

Failed JWST observations?

The JWST observations from 8 March are listed as "Failed Archived" on the STScI website,[7] which understandably prompted Lizardzap to edit the article, saying that the observations failed and were rescheduled. This may be technically true. However, the observations happened (preview), the raw data is available online, and it definitely seems usable. I've looked at the images myself, as have others (tagging Exoplanetaryscience and Nrco0e who I know have done so as well), and I noticed no issues with that part of the data (there were other files that I didn't look at). I am certain that astrometry will be possible, so the "failed" part is probably about some other objective. I'm not sure what this is about, and if Lizardzap are misinterpreting the status. I realize that "I've looked at it myself" is quintessentially WP:OR. What do we do? Renerpho (talk) 11:35, 16 March 2025 (UTC)

To expand on my previous comment, I believe this is a case of misinterpreting what the STScI website is actually saying. It's clear that some of the objectives were not met, and that the observations were rescheduled to complete this. Reading anything else into the word "failed" goes to far (in my opinion). Renerpho (talk) 11:44, 16 March 2025 (UTC)

I'd say just remove it and wait until those JWST observations are discussed in the news or a paper. I don't recommend interpreting unpublished data with non-expert judgement. Nrco0e (talk • contribs) 16:02, 16 March 2025 (UTC)

I am hearing that the NIRCam data from March 8th is fine (astrometry and lightcurve data), but that the MIRI observations have failed due to problems with guide star acquisition. But I have no source for that which can be quoted. I think Nrco0e is right, we should just wait for a reliable source to explain the situation. Renerpho (talk) 16:44, 16 March 2025 (UTC)

Today's JWST observations of 2024 YR4 seem to have worked as planned.[8] Next observations in the second half of April.Renerpho (talk) 20:52, 26 March 2025 (UTC)

Moonlight interference

@MrHalfBacon: In this edit, you write that The asteroid was not observed between 11–13 January, 8–15 February 2025, and 7 March to the present due to interference from moonlight (newly added content highlighted). Do you have a source for this? As of the time of that edit, the Moon was 109° from 2024 YR4, making interference nearly irrelevant. Aside from the possible problems with the "to the present" part, the asteroid has been observed by JWST on March 8th (see previous section on this talk page). It's just not true that it wasn't observed since March 7th. Renerpho (talk) 22:29, 19 March 2025 (UTC) Renerpho (talk) 22:29, 19 March 2025 (UTC)

Sorry, I must have been counfused- the reason i said it wasn't observed was because there had been nothing added to the risk table recently(observation arc has stayed at 71 days), and that the last observation on the table was march 6. Sorry i was confused, thank you for bringing this to attention. MrHalfBacon (talk) 22:49, 19 March 2025 (UTC)

@MrHalfBacon: No problem. The astrometry from the March 8th JWST data has not yet been submitted to the Minor Planet Center. I don't know when that will happen. The next observations with JWST are scheduled for next week (March 20-26). In the mean time, observations from before March 6th are added to the database every couple of days. For example, some data that had been taken on December 27th has been added on March 12th (search for "K24Y04R" on [9]). This also leads to gradual improvements. Renerpho (talk) 22:58, 19 March 2025 (UTC)