Abstract: The IAUMDC meteor shower database (SD) is confusing for several of the meteor showers (Koseki, 2020).  This paper presents the catalogue of clearly recognized meteor showers recorded by SonotaCo net video observations in the period 2009–2018 (SonotaCo, 2009).

 

1  Introduction

The author has checked the IAUMDC meteor shower database (SD) and compiled a catalogue of attractive meteor showers.  This paper provides its essential data for easy use.  The version of 2018 January 13 20h35m17s of the IAUMDC meteor shower database (SD) has been used.

The SD contains hundreds of meteor showers but many of them could not be confirmed by video observations.  Most of the daytime meteor showers are not observable by optical observations surely and there are important differences between radar and video observations when considering the meteor magnitude range.  Some meteor showers might have been lost or may have changed their activity level.

The most important cause of the existence of undetectable meteor showers in the SD is the difference in definition of what is a meteor shower.  There is no common and clear conception and that is why the list includes many false meteor showers. It is not possible to make an absolute distinction between meteor shower activities and the sporadic background.

 

2 Sun-centered ecliptic coordinates

Radiant points are described in equatorial coordinates usually and their radiant drifts are given as Δα and Δδ as well.  But, if we use ‘Sun-centered ecliptic coordinates’ to plot radiant points, we can almost eliminate the radiant drift during a week.

Figure 1 shows the star map in equatorial coordinates plotted in Hammer projection centered at (α, δ) = (0°, 0°).  The equator is on the x-axis and the ecliptic is shown with a yellow line.  Figure 2 shows the star map in ecliptic coordinates centered at the equinox, that is, (λ, β) = (α, δ) = (0°, 0°) and the ecliptic plane is now on the x-axis in turn.  The position of the Sun at the time of the Orionids maximum is drawn in Figure 2 as a red circle; a black circle for ANT and a black cross the APEX are added.  The Earth moves around the Sun and we see the Sun moving along the ecliptic; the ANT and the APEX also move and the meteor shower radiants drift as well.  If we set the position of the Sun as the origin, then the ANT, the APEX and the radiants become fixed.

 

Figure 1 – An equatorial star chart plotted in Hammer projection centered at (α, δ) = (0°, 0°). The red line is the equator, the yellow line is the ecliptic.

 

 

Figure 2 – An ecliptic star map plotted in Hammer projection centered at (λ, β) = (α, δ) = (0°, 0°). The red line is the equator, the yellow line is the ecliptic.

 

Figure 3 – The Sun-centered ecliptic star map at the Orionids maximum. The center of the map is at (λ–λʘ, β) = (270°, 0°).

 

 

Figure 3 shows such star map at the time of the Orionid maximum with the position of the Sun as the origin, which is called Sun centered ecliptic coordinates (λ–λʘ, β).  The reason why the center of Figure 3 is centered at
(λ–λʘ, β) = (270°, 0°) is the distribution of the meteor shower radiants; Figure 4 shows all the SD radiants.

The movement of the Earth around the Sun plays an important role in the distribution of the meteor shower radiants. It is very common to set the center of such figures at (λ–λʘ, β) = (270°, 0°).  We can easily point the major showers which include several entries in the SD as the crowded marks in Figure 4.  It is very clear that the Sun-centered ecliptic coordinates plot centered at (λ–λʘ, β) = (270°, 0°) is very suitable to show the radiant distribution over the entire sky. These coordinates correspond with the observed radiant distribution for the center of each meteor stream activity as shown in the meteor shower datasheets.

 

3 Selecting meteor showers

The author introduced the radiant density ratio (DR) to distinguish meteor shower activity from the sporadic background.  DR3, DR10 and DR15 are the sliding mean of the radiant density ratios within bins of 3 degrees in λʘ.

  • DR3: the density ratio within a circle of 3 degrees relative to a ring of 3 to 6 degrees.
  • DR10: the density ratio within a circle of 3 degrees relative to a ring of 6 to 10 degrees.
  • DR15: the density ratio within a circle of 3 degrees relative to a ring of 10 to15 degrees.

DR = 1 means that the radiant density is flat, with other words, no shower activity.  We can assume there may be some activity suggested when DR > 2.  The author has searched every line of the SD by using DR and selected several shower activities with DR > 5 at their maximum.

 

Figure 4 – Sun-centered ecliptic meteor shower radiants of the SD.

 

 

4 Calculations

4.1 Selection of the proper radiant position and the solar longitude of the activity

It is logic to select the entry in the SD which gives the highest density ratio DR value, as the candidate for the start of the calculation, but the SD has no information on the activity period.  The author has drawn the meteor activity profiles according to the value of DR and got the required period for the calculation.  It seems to be good to explain the process by showing KCG as an example; we select 0012KCG04 in this case.

 

Figure 5 – the radiant distribution of the KCG centered at (α, δ) = (285.0°,+50.1°) between λʘ = 128.7° and 152.7°.

 

4.2 Calculation of the distance from the selected point (center): Radiant distribution and the profile

It is common to represent the radiant point in Right Ascension and in declination (α, δ) and its radiant drift with the solar longitude as Δα & Δδ.  Figure 5 shows the radiant distribution of the KCG centered at (α, δ) = (285.0°,+50.1°) between λʘ = 128.7° and 152.7°.  The radiants appear distributed in an ellipse and this shape suggests that the radiant shifts with time.  We recognize the lines of the declination curve.  If we represent the radiant drift by Δα & Δδ, the radiant would pass through the curved path.  It is appropriate to express the radiant drift by using (x, y) coordinates centered at the selected radiant point represented by the coordinates (λ–λʘ, β).

We calculate the distance from the selected point expressed in (λ–λʘ, β) and draw the radiant distribution between 12 degrees earlier and later from the selected solar longitude of the activity in the case of KCG (see Section 6 ‘Explanation of the meteor shower datasheets’ as well as the datasheet for the KCG).  Figure 6 shows the same KCG data in the Sun-centered ecliptic coordinates centered at
(λ–λʘ, β) = (161.5°, 71.9°) and then the elliptic shaped distribution becomes smaller.  We should represent the radiant point in Sun-centered ecliptic coordinates (λ–λʘ, β) not in equatorial coordinates (α, δ). The y-axis runs through the selected λ–λʘ value, which is, 161.5°. The scale is in degrees.

We could move on to ‘4.4 Calculation of the linear regression of λ–λʘ and β on λʘ’ for the usual cases but the situation with the KCG is special; it is better to explain the process for such a special case.

 

Figure 6 – KCG data in the Sun-centered ecliptic coordinates centered at (λ–λʘ, β) = (161.5°, 71.9°)

 

Figure 7 – KCG data in the Sun-centered ecliptic coordinates rotated counterclockwise over 20° centered at (λ–λʘ, β) = (161.5°, 71.9°), slightly changed to (168.0°, 74.0°).

 

The kappa Cygnid shower (KCG) has three specific characteristics; the radiant area is inclined to the longitude line and elongated, and the radiants in the shower database are widely spread.  First, we rotate the y-axis –20 degrees, that is, 20 degrees counterclockwise and we rename the new coordinate as (x’, y’).  Secondly, we extend the search area to Δx’ < 3° and Δy’ < 6°, to have the elliptic shape in order to enclose the elongated area.  Thirdly, we need to move the preliminary center from (λ–λʘ, β) = (161.5°, 71.9°) to (λ–λʘ, β) = (168.0°, 74.0°) and the center of the activity period from λʘ =140.7° to λʘ =142.0°.

 

4.3 Calculation of the radiant distribution around the estimated center

The radiant distribution in Figure 7 appears still elongated which is often the case.  This ellipse shape means that the radiant shifts during the activity period of Δλʘ = 12°, although the elliptic shape of the radiant distribution can be natural in some cases.  We test whether the radiant drift is real by calculating the preliminary linear regression of x and y in function of λʘ, in the case of the kappa Cygnids (KCG) and some others we use x’ and y’ instead of x and y.  Because the radiants are dispersed by the drift itself and because the selected radiant point is tentative, we select the radiant data within a distance of 3 degrees from the center, Δr < 3° is most common for the usual cases.  We calculate the linear regression for the period of Δλʘ earlier or later than the selected λʘ. Both values Δr and Δλʘ are shown in each meteor shower datasheet. If we would calculate it for a longer time span, the results might be dispersed by the uncertainty of the tentative data.  Figures 8, 9 and 10 show the linear regressions of x’, y’ and vg for KCG at the first step of the iterative approach.

Figure 8 – The linear regression of x’ in function of λʘ.

 

Figure 9 – The linear regression of y’in function of λʘ.

 

Figure 10 – The linear regression of vg in function of λʘ.

 

4.4 Calculation of the radiant drift

We use the first linear regression described in point 4.3 to estimate the radiant drift and to calculate the distance from the estimated radiant drift for every radiant as shown in Figure 7.  We continue to regenerate similar regressions as shown in Figures 8, 9 and 10 by adding and removing radiant points until the regression results for x and y (x’ and y’ in case of KCG) converge in this iterative approach. We ignore the result for vg, because it has no significant effect on the final result.  Figures 11, 12 and 13 show the result of the 10th and final regression for the kappa Cygnids (KCG).  The radiant distribution becomes more compact (for an example see Figure 14) and we can easily convert the radiant drift (x, y) or (x’, y’) into (λ–λʘ, β) and (α, δ) coordinates (see also the KCG sheet).

Figure 11 – The linear regression of x’ in function of λʘ.

 

Figure 12 – The linear regression of y’ in function of λʘ.

 

Figure 13 – The linear regression of vg in function of λʘ.

 

We can select the possible shower members using two conditions:

  • The distance r between the radiant point of the candidate and the reference should be within the radius r<= 3° in case of the KCG, Δx’ < 3° and Δy’ < 6°;
  • The time of the event should be within the established search period.

 

Figure 14 – KCG data in the Sun-centered ecliptic coordinates rotated counterclockwise over 20° centered at (λ–λʘ, β) = (161.5°, 71.9°), slightly changed to (168.0°, 74.0°).

 

The selected radiant points show a change in time, expressed in solar longitude λʘ.  In order to include more candidate shower radiants, the iterative procedure with linear regressions is applied until the iteration converges.  We calculate the linear regression of (λʘ, x) and (λʘ, y) where (x, y) are the coordinates of the radiant distribution centered at the shower radiant which is the origin shown in Table 3 and explained in Appendix 1. The y-axis runs through the origin λ−λʘ (scales are in degrees).

 

5 Results

Table 1 lists the basic results of this survey. The column headings of this table are as follows:

  • is the IAUMDC shower number;
  • Code is the three-character code shower identification;
  • Name is meteor shower name according to the IAU;
  • DRmax is the density ratio value of DR15 at the maximum in general (* and # correspond to DR3 and DR10 respectively);
  • Nmax is the number of radiants within 3 degrees from the estimated radiant center at the time of the maximum.
  • λʘDR is the suggested maximum based on the density ratio DR;
  • λʘDR and λʘN are not identical and the difference can be several degrees in some cases. Therefore, it is convenient to give the most probable maximum λʘ; this corresponds to the maximum in Figure 16 (graph at right marked in yellow). λʘ was selected for the best fitting activity profile for each observed profile in the graphs marked in yellow and orange in Figure 16.  The radiant (α, δ), vg and the orbital elements in Table 2 are obtained from the regression result for this λʘ;
  • λʘstart and λʘend represent the possible shower activity period determined mainly by the condition DR > 2.

 

Table 1 – The list of 82 meteor showers presented in the datasheets; column headers see above. Click on the code or name of the shower to view the datasheet for this shower.

No. Code Name DRmax Nmax λʘDR λʘN λʘ λʘBeg λʘEnd α δ vg
450 AED April epsilon Delphinids 28.7 1.4 19.5 19.4 19.4 15 30 307.3 11.4 60.6
27 KSE kappa Serpentids 23.0 0.9 25.5 25.9 26.0 21 32 247.5 17.9 45.6
21 AVB alpha Virginids 15.0* 0.9 25.5 25.3 28.0 17 41 201.4 3.9 19.3
6 LYR April Lyrids 254.2 47.3 32.5 32.4 32.4 25 39 272.4 33.3 46.8
343 HVI h Virginids 15.8 1.2 41.5 41.6 41.0 34 44 203.7 -11.4 17.6
31 ETA eta Aquariids 554.9 43.0 44.5 44.9 45.0 25 75 337.5 -1.1 65.5
145 ELY eta Lyrids 40.8 3.7 50.5 49.4 49.6 46 55 290.6 43.5 43.9
152 NOC North. Daytime omega Cetids 55.1 0.4 52.5 53.7 53.0 44 63 17.1 19.7 40.1
171 ARI Daytime Arietids 151.6 0.6 73.5 73.8 73.8 68 86 41.4 23.7 40.5
431 JIP June iota Pegasids 16.8 2.2 94.5 93.8 93.8 93.4 95.4 331.5 29.3 58.6
372 PPS_0 phi Piscids 21.8 1.5 97.5 92.5 94.0 82 103 9.9 21.4 66.5
165 SZC Southern June Aquilids 75.8 1.0 103.5 108.2 104.0 95 110 318.3 -27.0 39.7
533 JXA July xi Arietids 34.4 1.2 102.5 108.5 105.5 93 125 32.7 7.8 68.4
372 PPS_1 phi Piscids 12.4 2.0 110.5 108.2 108.0 101 120 20.7 27.9 65.9
175 JPE July Pegasids 26.5 3.1 110.5 108.4 108.4 102 136 347.8 10.8 64.1
411 CAN c Andromedids 19.7 1.3 110.5 109.7 110.0 91 118 32.6 48.3 56.9
164 NZC Northern June Aquilids 89.6 1.5 101.5 112.7 113.0 81 129 319.4 -2.4 37.7
444 ZCS zeta Cassiopeiids 27.3 4.5 112.5 113.5 113.5 105 120 7.4 50.9 57.2
184 GDR July gamma Draconids 82.7 3.3 125.5 125.3 125.3 121 131 280.4 50.6 27.3
5 SDA Southern delta Aquariids 227.7 24.9 126.5 127.6 127.6 116 148 340.3 -16.3 40.3
1 CAP alpha Capricornids 85.3 8.5 127.5 127.5 128.0 105 142 306.4 -9.1 22.0
191 ERI eta Eridanids 32.4 3.5 127.5 134.5 134.0 108 168 40.9 -13.0 63.9
183 PAU Piscis Austrinids 4.8 0.9 136.5 135.0 135.0 129 138 353.3 -20.2 43.0
7 PER Perseids 660.3 323.3 139.5 140.0 140.0 112 159 48.1 58.0 58.8
12 KCG kappa Cygnids 19.7 2.7 145.5 141.7 141.0 129 154 286.2 50.2 22.2
AXD August xi Draconids 8.2 1.8 140.5 141.6 142.0 132 155 276.4 53.6 20.3
26 NDA Northern delta Aquariids 14.5 2.6 147.5 148.7 148.0 127 166 352.6 4.4 38.2
197 AUD August Draconids 14.5 1.6 154.5 153.2 153.0 140 166 259.1 62.8 21.3
523 AGC August gamma Cepheids 12.1 1.5 155.5 155.4 155.5 150 161 358.6 76.8 43.8
206 AUR Aurigids #21.3 2.5 157.5 158.5 158.4 149 166 91.0 39.2 65.4
33 NIA Northern iota Aquariids 6.4 1.4 160.5 168.0 162.0 153 183 358.5 3.3 29.9
208 SPE September epsilon Perseids 37.7 16.9 166.5 167.2 167.2 160 189 47.8 39.5 64.2
337 NUE nu Eridanids 8.9 2.1 169.5 168.3 168.0 158 181 68.2 0.7 65.7
81 SLY_0 September Lyncids 9.9 1.6 168.5 168.1 168.0 163 176 108.8 55.8 59.3
81 SLY_1 September Lyncids 4.5 0.8 187.5 187.9 185.0 173 190 110.9 47.9 65.4
221 DSX Daytime Sextantids 96.4 0.4 189.5 190.0 190.0 183 196 156.8 -3.3 32.1
281 OCT October Camelopardalids 23.6 10.3 191.5 192.7 192.7 192.1 192.8 167.3 78.6 45.4
333 OCU October Ursae Majorids 41.7 4.9 202.5 202.5 202.5 200 207 145.3 64.2 55.3
23 EGE epsilon Geminids *4.7 3.8 204.5 207.9 205.0 191 219 100.8 28.2 68.5
2 STA_SE Southern Taurids 38.6 7.9 199.5 207.6 205.0 180 230 39.0 10.5 28.2
480 TCA tau Cancrids 6.6 1.9 206.5 207.3 207.0 183 224 137.3 29.7 67.1
22 LMI Leonis Minorids 58.4 5.7 209.5 207.9 208.0 198 223 158.8 37.2 61.4
8 ORI Orionids 255.7 187.9 207.5 208.0 208.0 183 240 95.2 15.6 66.1
524 LUM lambda Ursae Majorids 8.7 1.7 214.5 214.5 214.7 207 219 158.0 49.4 60.8
526 SLD Southern lambda Draconids 9.8 2.6 221.5 221.4 221.4 219 225 161.3 68.2 48.6
388 CTA chi Taurids #4.2 1.8 222.5 221.9 222.0 210 231 63.9 27.2 40.1
445 KUM kappa Ursae Majorids 13.7 6.9 223.5 223.0 223.0 220 230 144.2 45.6 64.7
2 STA_SF Southern Taurids 72.2 19.2 221.5 223.0 223.0 198 256 53.7 14.4 27.7
18 AND Andromedids 15.6 2.0 230.5 224.1 230.0 213 245 22.2 32.0 16.9
17 NTA Northern Taurids 52.1 16.4 229.5 232.4 230.0 200 260 58.7 22.8 27.6
338 OER omicron Eridanids 11.4 1.2 243.5 224.5 231.0 210 250 58.6 -1.0 27.7
13 LEO Leonids 120.4 53.7 235.5 235.9 236.0 213 258 154.2 21.6 70.0
246 AMO alpha Monocerotids 6.9 2.4 240.5 239.8 239.8 237 243 117.6 0.7 61.6
488 NSU Nov. sigma Ursae Majorids 5.9 2.0 242.5 241.8 242.0 240 245 148.9 59.0 54.5
250 NOO November Orionids 34.5 10.7 249.5 249.4 248.0 228 265 91.4 15.4 42.3
340 TPY_0 theta Pyxidids 15.7 3.2 248.5 249.4 249.4 246 254 138.7 -25.6 59.7
257 ORS Southern chi Orionids 4.4 2.5 253.5 253.3 250.0 232 265 78.9 18.1 26.5
336 DKD December kappa Draconids 38.3 6.9 250.5 250.9 250.9 247 261 186.1 70.7 43.4
339 PSU psi Ursae Majorids 7.4 3.5 251.5 252.0 252.0 247 259 168.8 43.9 60.8
502 DRV December rho Virginids 8.8 1.8 252.5 253.4 253.4 247 271 185.5 12.9 68.2
16 HYD sigma Hydrids 103.2 24.3 254.5 252.6 255.0 240 284 124.3 2.9 58.8
19 MON December Monocerotids 59.4 11.3 257.5 258.6 259.0 241 273 101.0 8.2 41.0
529 EHY eta Hydrids 7.9 3.3 260.5 261.6 260.0 244 281 135.4 1.8 61.8
335 XVI December chi Virginids #35.4 2.4 259.5 256.4 260.0 244 279 189.4 -9.3 68.2
4 GEM Geminids 705.9 938.8 262.5 262.1 262.0 237 273 113.5 32.3 33.8
340 TPY_3 theta Pyxidids 7.3 2.1 265.5 266.6 266.6 256 288 154.3 -24.4 62.5
20 COM Comae Berenicids 33.3 20.5 267.5 266.1 267.0 249 320 160.4 31.1 63.0
428 DSV December sigma Virginids 11.7 2.3 263.5 276.3 270.0 244 304 207.2 4.6 66.1
15 URS Ursids 97.8 27.5 270.5 270.4 270.5 261 273 219.0 75.3 33.0
97 SCC Southern delta Cancrids 4.2 1.2 275.5 274.6 275.0 273 287 105.3 17.6 26.9
319 JLE January Leonids 6.7 2.1 282.5 282.0 282.0 277 287 147.5 23.9 52.0
10 QUA Quadrantids 289.1 255.5 283.5 283.3 283.3 275 296 230.0 49.7 40.2
331 AHY alpha Hydrids 52.2 2.5 285.5 286.4 285.0 264 302 127.9 -8.4 43.3
515 OLE omicron Leonids 7.0 1.5 289.5 289.0 289.0 269 302 137.7 9.6 41.7
96 NCC Northern delta Cancrids 4.0 1.4 287.5 290.1 290.0 274 307 122.0 22.5 27.6
323 XCB xi Coronae Borealids 16.1 0.7 294.5 297.3 295.0 289 300 249.9 30.0 45.5
341 XUM January xi Ursae Majorids 32.3 5.1 298.5 299.1 299.0 294 301 169.6 32.4 40.9
530 ECV eta Corvids 6.6 1.6 298.5 304.4 301.0 287 316 190.7 -17.7 67.6
429 ACB alpha Coronae Borealids 9.3 3.0 308.5 307.4 307.4 306 316 231.1 28.1 56.5
110 AAN alpha Antliids 5.5 0.5 313.5 313.1 313.1 302 317 158.3 -9.9 44.3
346 XHE x Herculids 15.6 2.0 350.5 351.3 351.3 346 360 254.4 48.6 35.4
11 EVI eta Virginids 22.6 2.5 358.5 356.9 357.0 348 5 185.3 3.3 27.0

 

Table 2 – Orbital elements. Code and λʘ are the same as in Table 1.  (λ–λʘ, β) is the radiant position in the Sun-centered ecliptic coordinates, e is the eccentricity, q is the perihelion distance, i is the inclination, ω is the argument of the perihelion, Ω is the ascending node, (λΠ, βΠ) represents the ecliptic coordinates of the perihelion. Click on the code of the shower to view the datasheet for this shower.

Code λʘ λ–λʘ β e q i ω Ω λΠ βΠ
AED 19.4 293.6 29.5 0.944 0.719 121.9 114.8 19.4 248.3 50.4
KSE 26.0 216.0 39.2 0.958 0.527 72.8 268.4 26.0 290.4 –72.7
AVB 28.0 170.3 12.0 0.721 0.724 7.0 250.5 28.0 278.4 –6.6
LYR 32.4 241.3 56.7 0.954 0.921 79.7 214.1 32.4 219.3 –33.5
HVI 41.0 165.1 –1.4 0.718 0.775 0.7 63.5 221.0 284.5 0.7
ETA 45.0 293.8 7.7 0.947 0.571 163.6 96.2 45.0 308.5 16.3
ELY 49.6 256.6 64.4 0.945 1.000 74.4 191.5 49.6 232.7 –11.0
NOC 53.0 330.4 11.5 0.956 0.097 38.5 32.0 53.0 79.0 19.2
ARI 73.8 332.3 7.4 0.970 0.084 26.0 30.3 73.8 101.5 12.7
JIP 93.8 252.5 37.9 0.964 0.900 112.4 219.9 93.8 256.2 –36.4
PPS_0 94.0 283.7 15.7 0.895 0.864 151.2 133.1 94.0 317.1 20.6
SZC 104.0 208.5 –10.4 0.956 0.098 33.9 148.1 284.0 76.7 17.1
JXA 105.5 284.7 –5.1 0.939 0.830 170.6 308.4 288.5 339.7 –7.3
PPS_1 108.0 281.7 17.7 0.856 0.906 148.0 139.7 108.0 323.7 20.0
JPE 108.4 244.7 14.8 0.961 0.583 148.5 262.6 108.4 207.0 –31.2
CAN 110.0 298.2 32.9 0.910 0.684 112.6 108.3 110.0 339.3 61.2
NZC 113.0 208.0 12.7 0.932 0.129 34.5 324.2 113.0 82.3 –19.4
ZCS 113.5 278.1 42.8 0.946 0.996 107.5 163.4 113.5 298.6 15.8
GDR 125.3 168.1 73.2 0.953 0.977 40.1 202.7 125.3 323.0 –14.4
SDA 127.6 208.1 –7.4 0.968 0.081 26.4 150.5 307.6 100.7 12.6
CAP 128.0 178.5 9.9 0.755 0.602 7.2 266.9 128.0 34.9 –7.2
ERI 134.0 260.0 –27.4 0.922 0.949 132.0 29.9 314.0 292.9 21.7
PAU 135.0 210.7 –15.9 0.965 0.122 55.0 142.3 315.0 111.1 30.1
PER 140.0 283.1 38.4 0.924 0.948 113.0 150.0 140.0 332.7 27.4
KCG 141.0 163.6 71.7 0.703 0.972 33.9 205.5 141.0 342.6 –13.9
AXD 142.0 144.6 76.6 0.651 0.998 31.6 195.9 142.0 335.7 –8.3
NDA 148.0 206.9 7.0 0.953 0.102 20.7 327.5 148.0 117.2 –10.9
AUD 153.0 60.9 84.0 0.638 1.010 34.0 177.3 153.0 330.7 1.5
AGC 155.5 263.7 63.6 0.876 1.006 75.5 187.7 155.5 337.4 –7.5
AUR 158.4 292.4 15.7 0.952 0.670 148.3 108.1 158.4 47.4 30.0
NIA 162.0 198.0 3.6 0.852 0.258 5.3 308.1 162.0 110.2 –4.2
SPE 167.2 249.1 20.9 0.952 0.717 139.2 245.8 167.2 287.9 –36.6
NUE 168.0 258.5 –20.9 0.882 0.902 142.4 38.9 348.0 315.4 22.5
SLY_0 168.0 294.5 33.2 0.950 0.761 115.6 119.9 168.0 24.9 51.4
SLY_1 185.0 280.3 25.6 0.929 0.940 135.0 150.6 185.0 26.8 20.3
DSX 190.0 329.8 –12.1 0.865 0.145 25.7 212.6 10.0 219.9 –13.5
OCT 192.7 281.5 61.9 0.915 0.991 77.6 169.0 192.7 10.3 10.7
OCU 202.5 279.0 46.7 0.920 0.979 100.7 164.2 202.5 25.5 15.5
EGE 205.0 254.6 5.1 0.906 0.778 170.3 237.4 205.0 328.0 –8.1
STA_SE 205.0 194.9 –4.5 0.823 0.318 5.6 120.6 25.0 145.7 4.9
TCA 207.0 283.9 12.7 0.813 0.832 156.3 129.2 207.0 75.3 18.1
LMI 208.0 297.8 26.1 0.961 0.619 124.9 103.2 208.0 95.7 52.9
ORI 208.0 247.0 –7.7 0.932 0.579 163.7 82.4 28.0 305.9 16.1
LUM 214.7 284.2 36.9 0.973 0.918 115.2 147.8 214.7 49.7 28.8
SLD 221.4 264.9 53.6 0.725 0.985 88.1 190.5 221.4 41.8 –10.5
CTA 222.0 204.8 5.8 0.970 0.109 17.1 324.0 222.0 187.2 –9.9
KUM 223.0 267.7 29.5 0.911 0.987 129.4 187.7 223.0 38.1 –6.0
STA_SF 223.0 191.9 –4.7 0.821 0.365 5.3 113.7 43.0 156.8 4.9
AND 230.0 162.8 21.0 0.722 0.799 9.9 237.3 230.0 106.9 –8.3
NTA 230.0 191.4 2.4 0.820 0.370 2.7 293.0 230.0 163.0 –2.5
OER 231.0 185.1 –20.8 0.863 0.515 19.5 92.0 51.0 143.1 19.5
LEO 236.0 272.3 10.2 0.855 0.985 162.2 172.8 236.0 62.9 2.2
AMO 239.8 239.7 –20.0 0.956 0.471 133.3 94.0 59.8 323.9 46.6
NSU 242.0 245.0 42.9 0.919 0.808 99.2 231.5 242.0 50.6 –50.6
NOO 248.0 203.4 –8.1 0.990 0.121 23.6 139.8 68.0 210.3 15.0
TPY_0 249.4 261.7 –39.3 0.915 0.957 112.3 20.1 69.4 61.5 18.6
ORS 250.0 189.4 –4.9 0.801 0.411 5.0 108.1 70.0 178.2 4.8
DKD 250.9 242.8 61.6 0.888 0.928 72.7 209.0 250.9 80.2 –27.6
PSU 252.0 258.3 35.5 0.886 0.919 117.4 211.1 252.0 56.5 –27.3
DRV 253.4 286.5 14.0 0.930 0.782 153.6 124.8 253.4 125.6 21.4
HYD 255.0 230.9 –16.4 0.984 0.254 129.2 119.8 75.0 302.8 42.2
MON 259.0 202.3 –14.8 0.980 0.189 34.6 129.3 79.0 213.8 26.1
EHY 260.0 237.4 –14.5 0.958 0.360 142.4 107.3 80.0 328.6 35.6
XVI 260.0 292.4 –4.9 0.967 0.609 170.0 282.9 80.0 156.9 –9.8
GEM 262.0 208.0 10.5 0.888 0.146 22.7 324.1 262.0 228.3 –13.1
TPY_3 266.6 259.9 –32.4 0.872 0.928 122.8 28.6 86.6 70.2 23.7
COM 267.0 242.9 21.1 0.953 0.560 134.2 263.3 267.0 6.5 –45.4
DSV 270.0 293.5 14.8 0.952 0.609 149.2 102.6 270.0 165.4 29.9
URS 270.5 219.0 72.0 0.809 0.940 52.8 205.9 270.5 106.8 –20.3
SCC 275.0 189.6 –5.0 0.803 0.407 5.2 108.5 95.0 203.6 4.9
JLE 282.0 219.6 10.1 0.991 0.049 104.5 335.3 282.0 288.6 –23.8
QUA 283.3 276.7 63.7 0.625 0.979 70.7 171.9 283.3 100.6 7.7
AHY 285.0 207.8 –26.4 0.966 0.289 57.7 115.9 105.0 237.2 49.5
OLE 289.0 208.3 –6.4 0.971 0.075 23.5 151.0 109.0 262.1 11.1
NCC 290.0 189.4 2.3 0.820 0.400 2.4 288.5 290.0 218.5 –2.3
XCB 295.0 306.5 51.4 0.830 0.789 78.2 124.3 295.0 98.2 54.0
XUM 299.0 218.0 25.6 0.855 0.217 66.9 313.7 299.0 276.7 –41.7
ECV 301.0 255.9 –12.0 0.814 0.808 157.5 53.1 121.0 70.1 17.8
ACB 307.4 271.3 44.8 0.874 0.984 103.9 176.7 307.4 128.2 3.2
AAN 313.1 210.7 –17.7 0.960 0.143 57.2 138.2 133.1 287.3 34.1
XHE 351.3 246.8 70.4 0.679 0.979 60.3 195.6 351.3 179.2 –13.5
EVI 357.0 186.6 5.1 0.817 0.447 5.2 283.1 357.0 280.1 –5.0

 

Figure 15 – Radiant drift estimation for CAN (#0411), for the explanation, see appendix 1.

 

Appendix 1: Calculation of radiant drift by using the regression data

It is useful for the readers to show an example of the EXCEL program to get the radiant coordinates from the radiant drift analysis.  The Excel sheet is shown in Figure 15. First you must copy the regression parameters from Table 3 in the input cells marked in red in Figure 15.  The Excel formulae for the computed cells are as follows:

  • A3 = 90
  • B3 = $E$2*A3+$F$2
  • C3 = $G$2*A3+$H$2
  • D3 = SQRT(B3^2+C3^2)
  • E3 = DEGREES(ATAN(C3/B3))
  • F3 = IF(B3>0,90-E3,270-E3)
  • G3 = (COS(RADIANS(D3)) SIN(RADIANS($C$2))*SIN(RADIANS(J3)))/COS(RADIANS($C$2))/COS(RADIANS(J3))
  • H3 = DEGREES(ASIN(SIN(RADIANS(D3))*SIN(RADIANS(F3))/COS(RADIANS(J3))))
  • I3 = IF(G3>0,$B$2-H3,IF($B$2-180+H3<0, $B$2+180+H3,$B$2-180+H3))
  • J3 = DEGREES(ASIN(SIN(RADIANS($C$2))*COS(RADIANS(D3))+COS(RADIANS($C$2))*SIN(RADIANS(D3))*COS(RADIANS(F3))))
  • K3 = SIN(RADIANS(J3))*COS(RADIANS($D$2))+COS(RADIANS(J3))*SIN(RADIANS(I3+A3))*SIN(RADIANS($D$2))
  • L3 =SIN(RADIANS(J3))*SIN(RADIANS($D$2))+COS(RADIANS(J3))*SIN(RADIANS(I3+A3))*COS(RADIANS($D$2))
  • M3 = COS(RADIANS(J3))*COS(RADIANS(I3+A3))
  • N3 = L3/M3
  • O3 = IF(L3>0,IF(N3>0,DEGREES(ATAN(N3)),DEGREES(ATAN(N3))+180),IF(N3>0,DEGREES(ATAN(N3))+180,DEGREES(ATAN(N3))+360))
  • P3 = DEGREES(ASIN(K3))
  • Q3 = $L$2*A3+$M$2

 

Table 3 – Origin for radiant drift calculation. Code is the same as in Table 1 and 2, but λʘ, λ–λʘ and β are different from Table2.  In the table below, λʘ, λ–λʘ and β are the origins for the radiant drift calculation (see the first line of Figure 16).  xa and yb are the coefficients and the constants in the linear regressions for the radiant drift defined as x = xa * λʘ + xb and y = ya * λʘ + yb. for the radiant drift in x and y.  Va and Vb are the coefficient and constant for the linear regression for the change in geocentric velocity in function of the solar longitude; Vg = Va * λʘ + Vb. Click on the code of the shower to view the datasheet for this shower.

Code λʘ λ–λʘ β xa xb ya yb Va Vb
AED 20.2 292.83 29.85 –0.1324 1.92 0.3387 –6.92 –0.0486 61.50
KSE 25.9 216.67 38.35 0.1666 –3.85 0.2559 –5.82 –0.2350 51.66
AVB 27 168.65 11.82 0.4496 –14.21 0.1783 –4.79 –0.1459 23.39
LYR 32.4 240.65 56.72 –0.4016 12.67 –0.2946 9.53 0.3495 35.43
HVI 40.6 165.58 –1.28 0.7416 –29.96 –0.0533 2.05 –0.2392 27.41
ETA 46.3 293.34 7.72 0.2420 –11.31 0.0627 –2.82 0.0791 61.91
ELY 50 257.20 64.11 0.2011 –9.70 0.3545 –17.27 –0.4497 66.20
NOC 52 329.65 12.32 0.3188 –17.62 0.2594 –14.56 0.0781 35.94
ARI 77 331.58 7.34 0.2829 –21.63 –0.0422 3.17 0.1537 29.14
JIP 94 252.76 37.51 –0.0695 6.73 –0.3205 30.46 1.2844 –61.86
PPS_0 94 282.38 16.40 0.1382 –14.23 0.1722 –16.83 0.0225 64.34
SZC 104 209.24 –11.26 0.0953 –9.23 –0.1579 17.30 –0.0511 45.01
JXA 107.3 284.80 –5.11 0.2112 –22.81 0.0844 –9.12 0.0418 63.91
PPS_1 109.6 281.88 19.57 0.2210 –23.71 –0.1459 13.94 0.1004 55.09
JPE 110 244.23 14.25 0.1030 –11.61 –0.0712 8.24 –0.0547 69.98
CAN 107 298.11 32.89 –0.0145 1.56 –0.0134 1.45 0.0256 54.12
NZC 108.09 208.79 13.30 0.1089 –11.56 0.0267 –3.63 –0.1267 52.01
ZCS 111.5 277.80 43.02 –0.2220 25.01 –0.2755 31.09 0.3677 15.47
GDR 124.6 167.94 73.05 0.4031 –50.55 0.1709 –21.29 –0.3667 73.22
SDA 126.8 208.78 –7.36 0.2894 –36.24 –0.1146 14.55 –0.1534 59.88
CAP 127.9 179.32 9.87 0.4127 –52.03 0.1168 –14.93 –0.1956 47.01
ERI 137.6 260.57 –27.33 –0.0135 2.34 0.0397 –5.41 0.0090 62.74
PAU 135.1 210.82 –16.73 0.1632 –21.90 –0.0197 3.49 0.0078 41.95
PER 137 283.28 38.35 –0.0097 1.47 –0.0647 9.08 0.0133 56.96
KCG 142 168.00 74.00 –0.3505 50.80 0.5750 –83.31 0.1739 –2.30
AXD 140 146.58 77.22 0.2201 –30.80 1.2161 –173.26 0.1610 –2.54
NDA 147 207.28 6.94 0.1106 –16.00 0.0460 –6.79 –0.0956 52.38
AUD 155 47.53 81.56 0.6911 –107.13 –1.3007 201.61 –0.1622 46.11
AGC 154.9 263.54 63.98 0.1228 –19.14 0.1199 –19.05 0.1128 26.23
AUR 158 292.56 15.86 0.0849 –13.28 0.1650 –26.25 –0.0197 68.50
NIA 165 198.02 4.34 0.0010 –0.09 0.0104 –2.36 –0.0151 32.33
SPE 167.1 248.75 20.79 0.0496 –8.62 –0.1884 31.57 0.0485 56.08
NUE 167.9 259.26 –20.67 0.0606 –9.49 0.2094 –35.46 0.0405 58.88
SLY_0 167 294.70 32.27 –0.2511 42.35 0.3118 –51.43 –0.2224 96.65
SLY_1 186 278.78 25.99 0.1699 –32.84 –0.0899 16.25 0.0989 47.11
DSX 189.2 329.82 –11.84 –0.0400 7.66 0.0809 –15.60 –0.1431 59.28
OCT 192.6 281.04 62.25 0.7074 –136.52 –0.7154 137.49 –0.5271 146.99
OCU 202 278.95 46.84 –0.4279 86.64 –0.0284 5.58 –0.2001 95.83
EGE 204.1 254.73 5.17 0.2304 –47.05 –0.0754 15.42 –0.0693 82.71
STA_SE 202.6 194.82 –4.45 0.2716 –55.79 –0.0273 5.49 –0.1127 51.35
TCA 206 284.80 12.39 0.2141 –43.47 0.2167 –44.55 0.0150 63.97
LMI 209.6 297.93 26.16 –0.0619 12.96 0.0724 –15.13 –0.0189 65.36
ORI 209 246.73 –7.62 0.2690 –56.27 0.0811 –16.95 –0.0750 81.65
LUM 214.6 284.57 37.05 –0.0025 0.85 –0.0187 3.83 –0.0272 66.64
SLD 221 265.66 53.73 –0.2435 54.36 –0.0558 12.22 –0.1762 87.58
CTA 221 204.86 4.99 0.1459 –32.33 0.0115 –1.71 –0.1816 80.46
KUM 225 268.21 29.76 0.0489 –10.49 –0.0109 2.20 –0.2103 111.56
STA_SF 221.5 190.70 –5.00 0.4606 –103.89 –0.0682 15.51 –0.2770 89.50
AND 228.6 163.43 18.81 0.4817 –110.15 0.5235 –118.21 –0.2009 63.07
NTA 228 191.71 2.11 0.2650 –60.65 0.0151 –3.16 –0.1467 61.31
OER 231 184.40 –21.54 0.2965 –69.16 –0.2653 62.05 –0.1345 58.78
LEO 235.4 272.26 10.17 0.3138 –74.06 –0.1771 41.86 0.0669 54.27
AMO 239 239.65 –19.91 0.3379 –81.06 0.1829 –43.95 0.0333 53.63
NSU 241.6 244.91 42.93 –0.0529 12.74 –0.1442 34.84 0.5255 –72.69
NOO 246.1 203.71 –8.14 0.2890 –71.35 –0.0594 14.79 –0.1545 80.62
TPY_0 249.4 261.96 –39.09 0.1434 –35.59 0.3144 –78.63 0.4161 –44.09
ORS 247.6 190.26 –5.21 0.2198 –54.13 –0.0137 3.69 –0.0986 51.17
DKD 251.7 243.25 61.57 –0.2642 66.50 0.1677 –42.02 0.0042 42.32
PSU 252.6 258.42 34.92 –0.1819 45.96 –0.1485 37.99 0.1914 12.59
DRV 256 285.61 14.89 0.1120 –29.21 0.2576 –66.18 –0.0533 81.71
HYD 257.5 230.89 –16.81 0.1076 –27.45 –0.0019 0.89 –0.0720 77.18
MON 261 202.24 –15.05 0.2968 –76.90 –0.0894 23.37 –0.1885 89.86
EHY 260.7 237.33 –14.70 0.1444 –37.57 0.0630 –16.19 –0.0434 73.06
XVI 263.7 291.42 –5.15 0.2593 –68.34 –0.0716 18.91 0.0283 60.82
GEM 260 208.05 10.39 0.1009 –26.41 –0.0465 12.26 0.0942 9.07
TPY_3 272 260.34 –31.35 –0.0503 13.82 0.1946 –52.98 0.1269 28.61
COM 280 242.25 20.12 0.0471 –13.15 –0.0694 19.50 –0.0085 65.27
DSV 270 293.72 14.78 0.1250 –33.52 0.1076 –29.05 –0.0008 66.32
URS 271 218.48 72.07 0.1434 –38.93 0.6064 –164.11 –0.3422 125.62
SCC 284.1 188.71 –5.38 0.0427 –12.65 0.1279 –34.82 0.0256 19.83
JLE 281 219.61 10.35 0.3206 –90.41 –0.0500 13.87 0.0516 37.47
QUA 283.2 277.67 63.41 0.0331 –8.95 0.2554 –72.07 –0.1167 73.28
AHY 281.2 207.90 –26.55 0.2252 –64.05 –0.0128 3.79 –0.1206 77.71
OLE 290 207.98 –6.91 0.0666 –19.51 0.1395 –39.80 0.1756 –9.06
NCC 290 189.35 1.17 0.0724 –21.01 –0.0064 2.95 0.0342 17.69
XCB 295 305.32 51.10 –0.1280 37.01 0.0152 –4.15 0.0371 34.56
XUM 298 217.93 25.74 0.3447 –103.13 –0.1309 38.95 –0.2739 122.85
ECV 303.3 255.31 –11.50 0.1935 –58.77 0.1920 –58.26 0.0171 62.40
ACB 309.89 271.81 44.48 –0.3828 118.05 –0.4471 137.79 0.4245 –73.96
AAN 312 210.60 –17.67 0.0181 –5.80 –0.0760 23.80 0.0233 37.00
XHE 350 244.94 70.58 –0.3191 111.46 0.0334 –11.94 –0.2189 112.32
EVI 357 185.85 5.49 0.5153 –184.68 0.0696 –25.19 –0.2581 119.20

 

 

6  Explanation for the meteor shower datasheets

The first lines describe the initial data for the iterative search like given in Table 3, not the final results listed in Tables 1 and 2. For some meteor showers there is an extra comment added. The shower code in the shower database is mentioned with its number between parentheses.

 

Figure 16 – An example of a meteor shower datasheet, in this case for the c Andromedids (CAN#0411).

 

  • λʘ: the supposed time of maximum activity.
  • Δλʘ is the half width of the search period.
  • λg–λʘand βg are the initial geocentric Sun-centered ecliptic coordinates for the radiant (as given in
    Table 3).
  • Δr is the discrimination radius in which the shower radiants are counted and distinguished from the sporadic background.
  • The plot at left figure is the radiant plot, marked in green in Figure 16. This radiant distribution is plotted taking the radiant drift into account.
  • The activity profiles derived by different standards are shown at right. The upper right profile (marked in orange in Figure 16) shows the activity according to the density ratios (DR); these are obtained using a sliding mean for a 3 degrees bin in λʘ moved with steps of 1 degree in λʘ. The graph for Nr<= 3 represents the number of radiants counted within 3 degrees from the estimated reference radiant position in steps of one degree in λʘ.
  • The second figure at right (marked in yellow in Figure 16) displays the detail of the change in activity according to Nr<= 3; using a sliding mean with a time bin of one degree in λʘ moved in steps of1 degree.  The curve(s) are drawn by the author according to the estimated variation of the activity (Koseki, 2012). We make the activity profiles using two different methods; one with the fixed perihelion (labelled by ‘A’ or ‘B’) and another one with the rotation of the perihelion (labelled as ‘rotation’).  The first one is based on the hypothesis that the axis of the perihelion and the size of the orbit remain fixed.  The second method assumes that the orbital plane rotates around the axis of the ecliptic pole which is the usual explanation for radiant drift.  We compute the orbital evolution in function of the solar longitude for the encounter condition with the Earth and, then we can obtain the estimated activity profiles from the difference between the orbital elements at the maximum and the computed elements in function of time expressed in solar longitude.
  • Table 1 (marked in red in Figure 16) lists for each year the number of radiants counted within 3 degrees from the estimated radiant center of the meteor shower.
  • Table 2 (marked in blue in Figure 16) represents the summary of the upper right figure. λʘ stands for the center of the radiant count. However, λʘ= 12.5° means the count id for λʘ between 12 and 13. The decimal ‘.5’ does not mean we have an accuracy at this decimal.
  • Table 3 (marked in purple in Figure 16) shows the evolution of the orbital parameters during the activity period.

The range of the considered period maybe wider or shorter than the activity period.  The probable activity period is given in the final basic results (Table 1).  The intervals in λʘ are shorten for meteor showers with a short activity period or for showers with a sudden changing activity at the maximum, for instance AED and LYR are such cases.

 

References

Koseki M. (2012). “A simple model of spatial structure of meteoroid streams”. WGN, the Journal of the IMO, 40, 162–165.

Koseki M. (2020). “Confusions in IAUMDC Meteor Shower Database (SD)”. eMetN, 5, 93–111.

SonotaCo (2009). “A meteor shower catalog based on video observations in 2007-2008”. WGN, the Journal of the IMO, 37, 55–62.

 

Acknowledgment

It has been said we cannot get a general view of a meteor shower until we have completed twelve years of observations. The Moon moves twelve and one third times a year around the Earth and we can observe a meteor shower without lunar obstruction once in three years. The Earth moves around the Sun in 365 and one quarter days so that we encounter a different part of the meteoroid stream every quarter of a day and we need to wait four years until we can observe the same part of the shower activity.

SonotaCo network has completed this 12-year cycle in 2007–2018. We can review each meteor shower activity completely using the SonotaCo network results. “The activity of meteor showers recorded by SonotaCo Net video observations 2007–2018” owes very much to all the observers who participated in the SonotaCo network.