By Damir Šegon, Denis Vida and Paul Roggemans
Abstract: A short duration new meteor shower on a long period comet type orbit has been detected during May 2023 by the Global Meteor Network. Meteors belonging to the new shower were observed between 53.93° < λʘ < 54.80° (2023, May 15–16) from a radiant at R.A. = 300° and Decl.= +18° with a geocentric velocity of 59.7 km/s. The new meteor shower has been listed in the Working List of Meteor Showers under the temporary identification M2023-K1.
Introduction
A routine visual check of the daily radiant plots of the Global Meteor Network revealed a concentration of radiants about 10° from the gamma Aquiliids (GAQ, #0531) radiant, and visual inspection of plots for the previous and next night revealed that the possibly new shower has been active for only the night of 15–16 May 2023 (Figure 1). The initial search through the IAU database has shown this may be a new shower, and a deeper investigation has been made.
Method and results
We used the procedure as described for some recent cases of possibly new showers in Bootes and Draco (Šegon et al., 2023). The Southworth–Hawkins dissimilarity criteria DSH has been chosen for the analysis of the new radiant concentration. A first iteration revealed a clear concentration of orbits, as it can be seen on Figure 2. The Railey distribution fit pointed at a DSH value of 0.1 as the orbital similarity cutoff (Figure 3), which resulted in 15 orbits representing the possibly new meteor shower.
Figure 1 – Radiant plot of the Global Meteor Network data for 2023 May 15–16 in Sun-centered geocentric ecliptic coordinates. The new radiant is visible right (west) of the GAQ radiant and is marked by a red arrow.
Figure 2 – Histogram of the distribution of the DSH criterion values valid for the final mean orbit.
Figure 3 – Rayleigh distribution fit and DSH criterion cutoff.
Figure 4 – All non shower meteor radiants in geocentric equatorial coordinates during the shower activity. The pale diamonds represent the new shower radiants plots, error bars represent two sigma values in both coordinates.
The presence of non-shower radiants in the area around the possibly new shower (Figure 4) shows the cutoff to be reliable since the density of meteor radiants does not look affected after removing shower members (plotted as pale diamonds). The plot of the shower meteor radiants in equatorial coordinates shows a very compact group, with a standard deviation of the distances from the average radiant position of about a single degree (see Figure 5). The Π–i diagram shows a compact group of radiants too (Figure 6), without any other groups of radiants to be seen.
Figure 5 – The reverse of Figure 4, now the shower meteors are shown as circles and the non shower meteors as grayed out diamonds. Note that there are no other groups of meteor radiants to be seen in the vicinity of the possibly new meteor shower.
Figure 6 – The diagram of the inclination i against longitude of perihelion Π shows showing a distinct group of radiants without any other groups to be seen.
Figure 7 – The activity period with the number of orbits identified as new shower members.
The radiant of the possibly new shower lies in the constellation of Sagitta, near the 5.3-magnitude star 13 Sge. The activity of the shower has been detected between 53.93° and 54.80° of solar longitude (Figure 7), however we may round the activity to about one day. Only a single meteor had a positive magnitude, and the overall average brightness was –1.5 with all Sirius-bright meteors. On average, six GMN cameras captured the same event: only four meteors were captured from two locations, and a single one was detected from twenty-one (21) sites.
This case has shown one of the most important characteristics of the Global Meteor Network, namely the value to cover events as they happen all around the globe. The first meteor has been captured from the USA, followed by South Korea, New Zealand, Malaysia, followed by United Kingdom and the Netherlands, Brazil and back to the USA where the last meteor has been captured!
New shower or existing shower?
Before making claims that the detected activity qualifies to be listed as a new meteor shower, the known existing meteor showers active around this time from this part of the sky must be checked. The only suspect candidate is the gamma-Aquiliids (GAQ#0531) meteor shower, first reported by Šegon et al. (2014). In geocentric equatorial coordinates as well as in Sun- centered ecliptic geocentric coordinates, the radiant concentrations appear as close but distinct neighbors. As the new shower activity appears later than the GAQ-activity and west of it in radiant position, the off-set in radiant positions cannot be explained by radiant drift. The Tisserand relative to Jupiter proves both GAQ and
Table 1 – Known neighboring shower, gamma-Aquiliids (GAQ#0531, Shiba, 2023), compared to the new meteor shower, New (a) and New (b) derived by two different methods.
| GAQ | New (a) | New (b) | |
| λʘ (°) | 48.7 | 54.54 | 54.5 |
| λʘb (°) | 40.2 | 53.93 | 54.2 |
| λʘe (°) | 58.0 | 54.80 | 55.5 |
| αg (°) | 304.9 | 300.3 | 300.4 |
| δg (°) | +14.4 | +17.8 | +17.8 |
| Δαg (°) | 0.97 | – | – |
| Δδg (°) | 0.24 | – | – |
| vg (km/s) | 62.8 | 59.7 | 59.6 |
| λ (°) | 311.3 | 307.2 | 307.3 |
| λg – λʘ (°) | 262.7 | 252.8 | 252.8 |
| βg (°) | 33.0 | 37.4 | 37.5 |
| a (A.U.) | 27.5 | 300.9 | 79.4 |
| q (A.U.) | 0.985 | 0.903 | 0.9014 |
| e | 0.964 | 0997 | 0.989 |
| i (°) | 123.7 | 113.5 | 113.4 |
| ω (°) | 197.7 | 218.2 | 218.4 |
| Ω (°) | 48.7 | 54.4 | 54.5 |
| Π (°) | 246.4 | 272.6 | 272.9 |
| Tj | –0.49 | –0.45 | -0.40 |
| N | 40 | 15 | 9 |
the new shower are Long Period Comet-type orbits (Table 1). The orbits differ mainly by ~10° in inclination and ~26° in longitude of perihelion.
Further verification of the IAU MDC Working List of Meteor Showers (Jenniskens et al., 2020; Jopek and Kaňuchová, 2014; 2017; Jopek and Jenniskens, 2011; Neslušan et al., 2020) did not reveal any other nearby meteor shower activity.
Another search method
Another method has been applied to check this new meteor shower discovery. The starting point here can be any visually spotted concentration of radiant points or any other indication for the occurrence of similar orbits. The method has been described before (Roggemans et al., 2019). The main difference with the method applied in Section 2 is that three different discrimination criteria are combined in order to have only those orbits which fit different criteria. The D-criteria that we use are these of Southworth and Hawkins (1963), Drummond (1981) and Jopek (1993) combined. Instead of using a cutoff value for the D-criteria these values are considered in different classes with different thresholds of similarity. Depending on the dispersion and the type of orbits, the most appropriate threshold of similarity is selected to locate the best fitting mean orbit as the result of an iterative procedure.
Figure 8 – Radiant plot in geocentric Sun-centered ecliptic coordinates for different similarity thresholds, the radiant of the gamma-Aquiliids (GAQ#0531) is marked as a diamond.
This method detects 45 candidate orbits if we admit DD < 0.08, 30 for DD < 0.06, 20 for DD < 0.04 and 9 for DD < 0.02. The better the similarity, the narrower the observing window. The mean orbit computed according to Jopek et al. (2006) for the orbits selected using the method of Šegon et al. (2023) is listed as New (a) in Table 1, the mean orbit for the selection using the method of Roggemans et al. (2019) is listed under New (b). The dispersion in geocentric Sun-centered ecliptic coordinates is displayed in Figure 8. The position of the gamma-Aquiliids (GAQ#0531) is shown east (at right) of the new shower.
The concentration of the orbits of the newly discovered meteor shower appears very distinctly in the diagrams of the inclination against the longitude of perihelion (Figure 9) and the diagram of the inclination against the perihelion distance (Figure 10). In both diagrams the position of the gamma-Aquiliids (GAQ#0531) is marked as a diamond and appears clearly separated from the new meteor shower orbits.
Figure 9 – Diagram of the inclination i against the longitude of perihelion Π, the radiant of the gamma-Aquiliids (GAQ#0531) is marked as a diamond.
Figure 10 – Diagram of the inclination i against the perihelion distance q, the radiant of the gamma-Aquiliids (GAQ#0531) is marked as a diamond.
Comparing older data and other datasets
Looking up past years orbit data for Global Meteor Network (2018–2022, 722315 orbits), we find 35 orbits with DD < 0.08 and 7 with DD < 0.04, recorded in the period 2020–2022. The SonotaCo net orbit data (2007–2022, 443197 orbits) has 21 orbits with DD < 0.08 and only 3 with DD < 0.04, recorded in different years. EDMOND (2001–2016, 317831 orbits), has 16 orbits with DD < 0.08 and only 2 with DD < 0.04 in different years. The CAMS orbit data (2010–2016, 471582 orbits), has 24 orbits with DD < 0.08 and only 3 with DD < 0.04, recorded in different years between 2012 and 2016.
None of the major video orbit catalogues has previously recorded any trace of some concentration of orbits related to the new meteor shower.
Conclusion
A possibly new meteor shower in the constellation of Sagitta active for only about a day, has been found from the results of May 15–16, 2023 observations by Global Meteor Network. The resulting orbit is a typical long period comet one, but no connection to any known comet has been found meaning the parent body of this shower remains unknown. The new meteor shower has been listed in the Working List of Meteor Showers under the temporary identification M2023-K1.
Acknowledgment
The authors thank all people who support the Global Meteor Network by contributing meteor camera data or in any other way to help monitoring meteor activity around the clock worldwide. The Global Meteor Network results were obtained thanks to the efforts of the following volunteers: Adam Mullins, Aden Walker, Adrian Bigland, Adriana Roggemans, Alain Marin, Alan Beech, Alan Maunder, Alan Pevec, Alan Pickwick, Aled Powell, Alejandro Barriuso, Aleksandar Merlak, Alex Bell, Alex Haislip, Alex Hodge, Alex Jeffery, Alex Kichev, Alex McConahay, Alex Pratt, Alex Roig, Alexander Wiedekind-Klein, Alexandre Alves, Alfredo Dal’ Ava Júnior, Amy Barron, Anatoly Ijon, Andre Rousseau, Andrea Storani, Andrei Marukhno, Andres Fernandez, Andrew Campbell-Laing, Andrew Challis, Andrew Cooper, Andrew Fiamingo, Andrew Heath, Andrew Moyle, Andrew Washington, Andy Stott, Ange Fox, Angel Sierra, Angélica López Olmos, Ansgar Schmidt, Anthony Hopkinson, Anthony Pitt, Anton Macan, Anton Yanishevskiy, Anzhari Purnomo, Arie Blumenzweig, Arie Verveer, Attila Nemes, Barry Findley, Bart Dessoy, Bela Szomi Kralj, Bernard Côté, Bernard Hagen, Bev M. Ewen-Smith, Bill Cooke, Bill Wallace, Bill Witte, Bob Evans, Bob Greschke, Bob Hufnagel, Bob Marshall, Bob Massey, Bob Zarnke, Brenda Goodwill, Brendan Cooney, Brian Chapman, Brian Murphy, Brian Rowe, Bruno Bonicontro, Callum Potter, Carl Elkins, Carl Mustoe, Carl Panter, Charlie McCormack, Chris Baddiley, Chris Blake, Chris Dakin, Chris George, Chris James, Chris Ramsay, Chris Reichelt, Christian Wanlin, Christine Ord, Christof Zink, Christophe Demeautis, Christopher Coomber, Christopher Curtis, Christopher Tofts, Chuck Goldsmith, Chuck Pullen, Ciaran Tangney, Claude Boivin, Claude Surprenant, Clive Sanders, Colin Graham, Colin Marshall, Colin Nichols, Con Stoitsis, Creina Beaman, Daknam Al-Ahmadi, Damien Lemay, Damien McNamara, Damir Matković, Damir Šegon, Damjan Nemarnik, Dan Klinglesmith, Dan Pye, Daniel Duarte, Daniel J. Grinkevich, Daniela Cardozo Mourão, Danijel Reponj, Danko Kočiš, Dario Zubović, Dave Jones, Dave Mowbray, Dave Newbury, Dave Smith, David Akerman, David Attreed, David Bailey, David Brash, David Castledine, David Hatton, David Leurquin, David Price, David Rankin, David Robinson, David Rollinson, David Strawford, David Taylor, Dean Moore, Denis Bergeron, Denis St-Gelais, Dennis Behan, Derek Poulton, Didier Walliang, Dino Čaljkušić, Dmitrii Rychkov, Dominique Guiot, Don Anderson, Don Hladiuk, Dorian Božičević, Dougal Matthews, Douglas Sloane, Dustin Rego, Dylan O’Donnell, Ed Breuer, Ed Harman, Edgar Mendes Merizio, Edison José Felipe Pérezgómez Álvarez, Edson Valencia Morales, Eduardo Fernandez Del Peloso, Edward Cooper, Ehud Behar, Enrico Pettarin, Enrique Arce, Enrique Chávez Garcilazo, Eric Lopez, Eric Toops, Erwin van Ballegoij, Erwin Harkink, Ewan Richardson, Fabricio Borges, Fernando Dall’Igna, Fernando Jordan, Fernando Requena, Filip Matković, Filip Mezak, Filip Parag, Fiona Cole, Florent Benoit, François Simard, Frank Lyter, Frantisek Bilek, Gaétan Laflamme, Gareth Brown, Gareth Lloyd, Gareth Oakey, Garry Dymond, Gary Parker, Gavin Martin, Gene Mroz, Geoff Scott, Georges Attard, Georgi Momchilov, Germano Soru, Gilton Cavallini, Gordon Hudson, Graeme Hanigan, Graham Stevens, Graham Winstanley, Greg Michael, Gustav Frisholm, Guy Létourneau, Guy Williamson, Hamish Barker, Haris Jeffrey, Harri Kiiskinen, Hartmut Leiting, Heather Petelo, Heriton Rocha, Hervé Lamy, Herve Roche, Holger Pedersen, Horst Meyerdierks, Howard Edin, Hugo González, Iain Drea, Ian Enting Graham, Ian Lauwerys, Ian Parker, Ian Pass, Ian A. 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Brown, Peter Campbell-Burns, Peter Davis, Peter Eschman, Peter Gural, Peter Hallett, Peter Jaquiery, Peter Kent, Peter Lee, Peter McKellar, Peter Meadows, Peter Stewart, Peter Triffitt, Pető Zsolt, Phil James, Philip Gladstone, Philip Norton, Philippe Schaak, Phillip Wilhelm Maximilian Grammerstorf, Pierre Gamache, Pierre de Ponthière, Pierre-Michael Micaletti, Pierre-Yves Pechart, Pieter Dijkema, Predrag Vukovic, Przemek Nagański, Radim Stano, Rajko Sušanj, Raoul van Eijndhoven, Reinhard Kühn, Remi Lacasse, Renato Cássio Poltronieri, René Tardif, Richard Abraham, Richard Bassom, Richard Croy, Richard Davis, Richard Fleet, Richard Hayler, Richard Johnston, Richard Kacerek, Richard Payne, Richard Stevenson, Rick Fischer, Rick Hewett, Rick James, Ricky Bassom, Rob Agar, Rob de Corday Long, Rob Saunders, Robert Longbottom, Robert McCoy, Robert Saint-Jean, Robert D. 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Nielsen, Torcuill Torrance, Tosh White, Tracey Snelus, Trevor Clifton, Ubiratan Borges, Urs Wirthmueller, Uwe Glässner, Vasilii Savtchenko, Ventsislav Bodakov, Victor Acciari, Vincent McDermott, Vladimir Jovanović, Waily Harim, Warley Souza, Washington Oliveira, Wenceslao Trujillo, William Perkin, William Schauff, William Stewart, Wullie Mitchell, Yakov Tchenak, Yfore Scott, Yohsuke Akamatsu, Yong-Ik Byun, Yuri Stepanychev, Zané Smit, Zbigniew Krzeminski, Željko Andreić, Zhuoyang Chen, Zoran Dragić, Zoran Knez, Zoran Novak, Asociación de Astronomía de Marina Alta, Costa Blanca Astronomical Society, Perth Observatory Volunteer Group, Royal Astronomical Society of Canada Calgary Centre (list established 2 May 2023).
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