Μέγιστο βροχής διαττόντων "Δρακοντίδες" 8-9/10/201

[astrovox]

Κορυφώνονται οι "Δρακοντίδες" τη νύχτα 8 προς 9 Οκτωβρίου. Οι "Δρακοντίδες" είναι μια σχετικά απρόβλεπτη βροχή διαττόντων που κατά καιρούς έχει εκπλήξει τους παρατηρητές με απρόσμενα μεγάλη δραστηριότητα. Φέτος δεν αναμένεται κάποια αυξημένη δραστηριότητα αλλά οι ευνοϊκές συνθήκες Σελήνης και το γεγονός πως το ακτινοβόλο σημείο είναι αειφανές σημαίνουν πως ίσως αξίζει μια προσπάθεια.

 

Ο ΙΜΟ γράφει σχετικά:

 

The Draconids are primarily a periodic shower which produced spectacular, brief, meteor storms

twice last century, in 1933 and 1946, and lower rates in several other years (ZHRs ∼ 20–500+).

Most detected showers were in years close to when the stream’s parent comet, 21P/Giacobini-

Zinner, returned to perihelion, as it last did in 2012 February, producing EZHRs of ∼ 300 in 2011

October despite bright moonlight then, and a wholly unexpected outburst of chiefly very faint

meteors, detected primarily by the Canadian CMOR meteor radar system, on 2012 October 8.

The comet’s orbital period is currently about 6.6 years. Outlying maximum times from the recent

past have spanned from λ⊙ = 195 .◦036 (in 2011), equivalent to 2015 October 8, 20h50m UT,

through the nodal passage time above, to the end of a minor outburst in 1999 at λ⊙195 .◦76 (not

a perihelion-return year, but ZHRs reached ∼ 10–20), equating to 2015 October 9, 14h30m UT.

No predictions for unusual activity are in-force this October. However, as activity in recent years

has demonstrated, observers should be alert just in case, especially as October’s new Moon on

the 13th makes this a very favourable year. The Draconid radiant is north-circumpolar, at its

highest during the first half of the night, and Draconid meteors are exceptionally slow-moving.