- This topic has 6 replies, 2 voices, and was last updated 4 months ago by Alex Pratt.
-
AuthorPosts
-
31 July 2024 at 5:15 pm #623970Bill WardParticipant
Hi All,
As we edge towards darker skies and the Perseids I had the first clear night in a long while last night.
Caught this nice Type A (Mg/+Na) spectrum. The sodium emission left a brief wake.
See the usual assortment of pics below. I also caught it on another spectro system that showed the zero order meteor image itself (and a highly foreshortened spectrum too).
Alex also seems to have captured it on his north facing camera.
Roll on the Persieds.
Bill.Attachments:
31 July 2024 at 5:26 pm #623976Bill WardParticipantI caught a very similar meteor in 2019. Video is here https://youtu.be/XLveGtJsvk4?si=wDjZ9dKAGo6ymLf1
The one from this morning exhibited the same ablation/disintegration.
The resolution of this mornings one is significantly better but the spectral type/form are the same.
Whatever the mineralogy, the large sodium signal seems to indicate a particular meteor behaviour.
Another little insight into things…
Cheers,
Bill.31 July 2024 at 6:46 pm #623978Alex PrattParticipantIt was quite a cloudy night but the meteor was recorded on my Leeds_N UFO Capture camera. UFO Analyser gave it a provisional single-station classification as a mag -0.6 alpha Capricornid, which are relatively slow meteors with a geocentric velocity of 23 km/s.
Alex.
Attachments:
31 July 2024 at 7:10 pm #623983Bill WardParticipantJust for a clarification. The first three images have the time as 0119, this is BST. Last image is 0019 UT.
31 July 2024 at 7:55 pm #623984Alex PrattParticipantHi Bill,
Re your ‘melting meteor’ from 2019. We have a match in the NEMETODE dataset – a 2-station capture by Andy McCrea (Bangor, N Ireland) and myself. It suggests a mag 0 sporadic, detected at 90 km altitude and extinguished about 10 km lower, with a 12 km ground track. Its Vg was about 18 km/s, so particularly slow.
Having looked at only a few examples of this nature, they had slow Vg and/or shallow angles of attack to the atmosphere.
Alex.
Attachments:
1 August 2024 at 7:45 pm #624031Bill WardParticipantHi,
That’s great Alex.Considering that once anything glows, it’ll give off a “spectrum”, I wonder just how much the entry conditions affect the spectrum as I record it?
In real life so many variables and assumptions come into play. There’s a huge amount of theoretical work out there but as far as I can tell it still just boils down to observing and seeing what we get under any given conditions!Certainly the ones that seem to crumble away at lower speeds are fascinating. This is the project that the old WATECS, I mentioned elsewhere, will be turned to…. eventually.
Bill.
2 August 2024 at 11:54 pm #624044Alex PrattParticipantHi Bill,
You might have read the attached paper which suggests that meteors with slow Vg can produce sodium-rich spectra, irrespective of the meteoroids’ chemical composition.
Alex.
Attachments:
-
AuthorPosts
- You must be logged in to reply to this topic.