June Boοtids(JBO): 22 Ιουν ως 2 Ιουλ. Μέγιστο: 27 Ιουν. 2010

[Bi2L]

June Boötids(JBO): 22 Ιουν ως 2 Ιουλ. Μέγιστο: 27 Ιουν. 2010

πηγη imo.net http://www.imo.net/calendar/2010

 

Active: June 22–July 2; Maximum: June 27, 14h30m UT (λo = 95 .◦7), but see text;

ZHR = variable, 0–100+;

Radiant: α = 224◦, δ = +48◦; Radiant drift: see Table 6;

V∞ = 18 km/s; r = 2.2;

TFC: α = 156◦, δ = +64◦ and α = 289◦, δ = +67◦ (β = 25◦–60◦ N).

 

 

This source was reinstated on the Working List after its unexpected return of 1998, when ZHRs of 50–100+ were visible for more than half a day. Another outburst of similar length, but with ZHRs of ~ 20–50 was observed on 2004 June 23, a date before definite activity had previously been recorded from this shower. Consequently, the shower’s start date was altered to try to ensure future activity so early is caught, and we encourage all observers to routinely monitor throughout the proposed activity period, in case of fresh outbursts. Prior to 1998, only three more probable returns had been detected, in 1916, 1921 and 1927, and with no significant reports between 1928 and 1997, it seemed likely these meteoroids no longer encountered Earth. The dynamics of the stream were poorly understood, although recent theoretical modelling has improved our comprehension. The shower’s parent, Comet 7P/Pons-Winnecke, has an orbit that now lies around 0.24 astronomical units outside the Earth’s at its closest approach. Its most recent perihelion passage was in 2008 September. Clearly, the 1998 and 2004 returns resulted from material shed by the comet in the past which now lies on slightly different orbits to the comet itself. Dust trails laid down at various perihelion returns during the 19th century seem to have been responsible for the last two main outbursts. Four similar dust trails are predicted to encounter the Earth this year, laid down by the comet in 1819, 1825, 1830 and 1836, which may produce UT maxima around June 24, 03h53m,01h22m, 00h07m and June 23, 22h40m respectively. Activity is uncertain, but is not expected to be particularly high, so perhaps will be no better than at the 2004 return. Conditions for checking are very unfavourable from the mid-northern latitudes where the radiant is best-seen, with full Moon on June 26, aside from the prolonged – in some places continuous – twilight, but it is important to discover whether activity recurs at all, and if so when. The radiant is usefully accessible virtually all night, and all observing techniques can be employed. In terms of the apparently ‘early’ predicted peaks this time, VID suggested some June Boötids may be visible in most years around June 20–25, but that their activity was largely negligible except near λo = 92◦ (2010 June 23). Even stranger was that this activity originated from a radiant about ten degrees south of the visual one found in 1998 and 2004, close to α = 216◦, δ = +38◦.

[tolis45]

Βασιλη,

 

Κοιταξε το μυνημα μου στιs 12/06.

 

Μια εξαρση προμηνυοταν για τιs 23/24 Ιουνιου, αλλα με χαμηλο επιπεδο εμπιστοσυνηs.

Καποιεs αναφορεs εχουνε γινει στο tech.groups.yahoo.com/group/meteorobs/

τιs τελευταιεs μερεs για σημαντικο αριθμο JBO (> 0 που ειναι το συνηθεs!) εκεινη τη νυχτα

τιs οποιεs ομωs αντικρουουν αλλεs αρνητικεs αναφορεs.

 

Καλο θα ηταν, οποιοs ετυχε καλου καιρου απο τον ελληνικο χωρο εκεινη τη νυχτα

και εκατσε να κανει καταγραφη video η photo, να γραψει μια συντομη περιληψη

σε αυτη την σελιδα, η να στειλει αναφορα κατευθειαν στο ΙΜΟ.

 

Τα θεωρητικα μοντελα πιστοποιουνται (η πετιωνται στον καλαθο των αχρηστων)

μονο με τιs παρατηρησειs!

 

Τοληs

[tolis45]

Σύμφωνα με το Ηλεκτρονικό Τηλεγράφημα Νο 2357

του Κεντρικού Γραφείου Αστρονομικών Τηλεγραφημάτων (CBAT)

- το οποίο, δυστυχώς, δεν προσφέρεται για δημόσια προβολή -

μια μικρής έντασης έξαρση των Βοωτίδων του Ιουνίου (June Bootids) έλαβε χώρα

μεταξύ 22 ωρών UT της 23ης και 06 ωρών UT της 24ης Ιουνίου 2010.

O αντίστοιχος Ωριαίος Ζενίθιος Ρυθμός (ZHR) ήταν 5+-2 μετέωρα / ώρα.

Οι σχετικές παρατηρήσεις πραγματοποιήθηκαν οπτικά και με κάμερες βίντεο

χαμηλού επιπέδου φωτός (Low Light Level).

 

Τόλης.