A Repeat of the Gamma Delphinid Outburst?

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Radiant Position of the Gamma Delphinids (DEL)

Radiant Position of the Gamma Delphinids (DEL)




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On the evening of June 11, 1930, three members of the American Meteor Society (AMS) reported that they observed a flurry of meteor activity occurring between the hours of 2215 and 2245 (1015-1045pm EST) from Maryland, USA. These meteors were seen despite the fact that a nearly full moon was present in the sky during the entire display. No other reports of this activity was reported, leading to some doubts of the authenticity of this outburst. Of course one would not expect many meteor observers to be out observing under such unfavorable lunar conditions. In subsequent years this radiant was monitored but no further activity was seen on or near this date.

Peter Jenniskens, in his study of outbursts from long-period comets, has proposed that the 1930 event was real and may be repeated on Tuesday morning June 11, 2013. The expected time of maximum activity would be near 0828 Universal Time. This time corresponds to 4:28am EDT, 3:28am CDT, 2:28am MDT, and 1:28am PDT. This timing is favorable for all the Americas, extending west to the Hawaiian Islands. The radiant was reported to lie near the notable double star gamma Delphini, which lies near celestial coordinates 312 (20:48) +17. For observers in mid-northern latitudes this radiant rises in the eastern sky shortly after the end of dusk and is best placed high in the southern sky between 0400 and 0500 local daylight time.

To view this possible outburst one should seek out the darkest skies possible. Clear horizons devoid of trees and hills would also help. I would suggest starting your viewing session at least two hours prior to the expected maximum, in case it arrives early. While this activity can be seen in any portion of the sky, it would be best to view so that the radiant is included in your field of view so that you can verify if any activity can be associated with this radiant. These meteors would be of medium-swift velocity unless they appear near the radiant or close to the horizon. In these instances any gamma Delphinid meteors would move more slowly.

No one knows the strength of this display or whether it will occur at all. It would most likely be of short duration (less than one hour and perhaps as short as 15 minutes). This is not something one can stand outside and try to witness. Serious observers should be comfortable in a lounge chair and watch for at least an hour. I would not expect strong rates such that occurred with the Leonid outbursts near 2000. Rather these meteors are more likely to appear a minute or two apart. True Gamma Delphinid meteors would be moderately swift unless they appear near the radiant or near the horizon. In these case they would appear to travel with medium velocity. Unlike the 1930 display, the moon will not be a factor in 2013 as it will have set long before the predicted time of the outburst.

If your skies are clear the AMS encourages you to try and verify any activity from this source. Even reports with no activity will help. Be sure to share your observations (either positive or negative) with us as soon as possible after viewing. Reports may be emailed to: lunro.imo.usa@cox.net or one may use the AMS online report form (available to registered members).

Clear Skies!

Robert Lunsford

American Meteor Society





  • allison 10 years ago

    Does this article imply that Peter Jenniskens has associated the Delphinid stream with some particular comet? If so, which one? If not, then what is the basis for suggesting that there may be a reappearance in 2013?

    Reply to allison
  • Mark Newberry 10 years ago

    Observations of possible Dephinids –
    Observed from Lakewood , CO; 0220-0410 MDT; conditions were excellent for a light-polluted suburb.
    5 meteors observed, 3 were Delphinids (2 sporadic)
    track info
    0237 MDT – from Polaris toward Muscida (E of U Major pointers) – swift & bright
    0308 MDT – from Aldib (Draco) to Polaris – swift & very bright
    0314 MDT – Deneb (Cygnus) thru Cepheus tw Polaris – long, fast, varied in brightness ending with a flash. trail remained 4-7 secs
    No other meteors seen with Delphinids tracks by 0410 MDT

    Reply to Mark
  • Bob Hillenbrand 10 years ago

    FYI I saw one faint meteor which fit the descriptions at approximately 4:44 am – very fast, long trail ( 40 deg ), an
    faint ( +3 ish ) with hazy skies ( could make out the milky way ) with periodic clouds. Observed from approximately
    4:15 to 4:50. Location southeast of Daytona Beach, FL.

    Reply to Bob
  • Mike Lewinski 10 years ago

    Around 4:00am in Northern New Mexico I saw at least 3 very fast and very faint meteors that appeared to originate from Delphinus (all traveling northwest away from the apparent radiant). I had a camera pointed below it to the south, but these weren’t in my camera’s field of view and were too faint anyway.

    Reply to Mike
  • Steven Swisley 10 years ago

    Observation from Isla Vista, California:

    4am June 11, 2013,

    viewing southern horizon over ocean

    meteors traveling east to west, around Sagittarius

    3 brightness-low, color-white, speed-fast, length-short, no trail

    1 medium bright to bright, red, fast, long, moderate trail

    Reply to Steven
  • JOE 10 years ago

    In Troy, NY I saw an outburst of 1 bright meteor and 6 very faint meteors that originated from the eastern portion of the sky, but this was on Sunday June 9, 2013 at aprox. 10PM EST. The outburst lated about 2 or 3 minutes.

    Reply to JOE
  • Cecile 10 years ago

    Saw two outburst in the sky of Copenhagen, Denmark, at around 22.30 the night of the 11th June. There were at about 1-2 min interval. Very slow, orange, quite big, with no queue but a kind of halo of fire around it when it passed above my head.

    Reply to Cecile

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