In the first part of this article we reported on some notably bright meteors recorded by the Brazilian BRAMON network and Ukrainian MeteorsUA network during the “Big Spring Hole”, a period of decreased meteor activity lasting through spring months (in fact, from the latter half of January until the end of June). During this quiet period the Lyrids, eta Aquarids, and other showers make an appearance but usually with lower activity. Even sporadic activity during the period is lower, but strangely we are seeing see more of those heavyweight fireballs or “bolides” than at any other time of the year.
Let’s take a peek at some more interesting bolides from the EDMOND network database - and for our first candidate we don’t have to look very far! Our candidate for third place is a bolide that made an appearance right above our heads here in United Kingdom.
This bolide was recorded by UKMON’s Norman Lockyer, Clanfield, Wilcot stations at 18:30:20 UT.
Further observations were made by the Bradbury camera and by visual observer Damian Peach.
It was lucky that UKMON stations were able to capture this bolide at all; not one station recorded the end of event. It is thanks to 1 serendipitous photograph by Justin Whitaker from Bristol that we have data for this event in full.
This meteor was relatively slow with the Norman Lockyer station recording an event time of 3.2 seconds and angular speed 5.7 degrees per second. Wilcot station recorded 2.8 seconds and a similar angular speed. The Clanfield station recorded only 1 second of the event but a higher angular speed of 6.4 degrees per second. Based on our date we calculate a geocentric velocity of 12.1 km/s with orbital elements a = 4,038 AU, q = 0,979 AU, e = 0,757, i = 11,392°, peri = 168,206°, node = 326,801°. The initial altitude (HB) was 86.3km and terminal altitude (HE) was 30.1 km. The total track length was measured to be 63.4 km. This meteor was classified as Sporadic with brightness approximately -9.1 mag
The light curve from Justin’s image gave us also interesting results.
A 2D projected ground map and orbital elements in Solar System including deceleration are as follows:
This was a very slow bolide captured by CEMEeNt network stations Nydek (Martin Popek) and Kromeriz (Jakub Koukal) at 22:30:72 UT.
The absolute brightness was calculated at – 4.45 mag after light curve analysis.
Not that an initial velocity of 16.55 km/s and terminal velocity of mere 4.69 km/s might, in some situations, suggest the possibility of debris reaching the ground (see deceleration fit graph below). However, this does not seem likely in this case considering the relatively low absolute. From development of the absolute brightness the mechanical strength of the body was estimated to be 0.124 ± 0.022 MPa.
Geocentric velocity was just 11.7 km/s and orbital elements are a = 1,664 AU, q = 0,878 AU, e = 0,472, i = 8,342°, peri = 49,716°, node = 161,063°. The initial altitude (HB) was 83.7km and terminal altitude (HE) at 31.6 km. The total track length was 84.2 km. Again, this meteor was declared as Sporadic type with radiant RA = 134,8°, DEC = −9,2°.
Yet another bolide from Brazil’s BRAMON network detected by Mogi das Cruzes station (Marco Mastria) and Campinas station (Wilson Alves) detected at 21:44:19 UT.
The Campinas station recorded an event time of 6.907 seconds and an angular speed of just 3.55 degrees per second. The Mogi das Cruzes station recorded an event time of 7.407 seconds and even smaller angular speed of 2.142 degrees per second. The absolute magnitude was calculated at -5.0 mag.
Geocentric velocity was very low, just 10.6 km/s with orbital elements a = 1,5 AU, q = 0,933 AU, e = 0,379, i = 12,3°, peri = 222,2°, node = 31,5°. Initial and terminal height combined with atmospheric length are showing at high zenith angle. HB = 80.1 km, HE = 49.2 km and total track of 131.5 km. Meteor was determined to be of Sporadic type with observed radiant RA = 205,8°, DEC = 35,5°.
Well, there we have it. Largest and brightest heavyweight fireballs across EDMOND network in just four months of observations.
SOURCE: Jakub Koukal, Richard Kacerek, Peter Campbell-Burns