ВНИМАНИЕ! На форуме начался конкурс - астрофотография месяца АПРЕЛЬ!
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Electronic Telegram No. 4692Central Bureau for Astronomical TelegramsMailing address: Hoffman Lab 209; Harvard University;20 Oxford St.; Cambridge, MA 02138; U.S.A.URL http://www.cbat.eps.harvard.edu/index.htmlPrepared using the Tamkin Foundation Computer NetworkALPHA MONOCEROTIDS 2019P. Jenniskens, SETI Institute and NASA Ames Research Center; and E.Lyytinen, Helsinki, Finland, report that a significant return of the alphaMonocerotid meteor shower (IAU shower 246, AMO) is expected on Nov. 22,centered at 4h50m UTC. Past dust-trail calculations (cf. Lyytinen andJenniskens 2003, Icarus 162, 443) were re-evaluated assuming now that pastoutbursts were caused by the one-revolution dust trail of a long-periodcomet with a shorter orbital period of about 500 years. From this, the 2019encounter is expected at solar longitude 239.308 degrees (equinox J2000.0),and the earth is expected to cross the dust trail slightly further out fromthe sun. If the trail was crossed through its center in 1925 and 1935, thenthe earth passed 0.0002 AU from the trail center (inside the trail) in 1985and 1995. The heliocentric-distance difference of dust trail minus earthorbit will be -0.00016 AU in 2019. Because the uncertainty of where thetrail center is, the distance could range between -0.00036 and +0.0000 AU.Depending on that distance, peak rates in 2019 could be about similar to, orin excess of, those observed in 1995, when the zenith hourly rate was 400meteors/hr in the minute centered on the peak (cf. Jenniskens et al. 1997,Ap.J. 479, 441). Past dust-trail encounters were very brief, with afull-width-at-half-maximum of only 0.29 hr.NOTE: These 'Central Bureau Electronic Telegrams' are sometimessuperseded by text appearing later in the printed IAU Circulars.(C) Copyright 2019 CBAT2019 November 4 (CBET 4692) Daniel W. E. Green
яркий спутник пролетел через зенит с запада на восток в 7-30