メタデータ

項目	値
Designation	57P/duToit-Neujmin-Delporte
Type	P
Perihelion (tp_cal, UTC)	2015-05-22T12:24:41.207040Z
Orbit solution date (soln_date, UTC)	2025-09-10T11:27:46Z
Obs used	1389
NEO	-
M1	15.800
K1	4.500
PC	-

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2018-03-03.0000000
e	0.49981547
q (au)	1.725627
a (au)	3.449981
i (deg)	2.848605
Ω (om, deg)	188.808603
ω (w, deg)	115.131778
M (ma, deg)	156.189430

等級

散乱 + 全体線形

$$ M_a = (9.577 + 4.993\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	9.577
n	4.993
gf	1.000
gb	-0.998
k	1.000
δ90	10.000

パラメータ	記号	範囲	説明
太陽・地球距離が1 AUのときの絶対等級	H0	-5 to 20	彗星の固有の明るさ
測光スロープパラメータ	n	2 to 6	太陽距離に対する明るさ変化率
前方散乱非対称係数	gf	0.8 to 1	前方散乱の強さ
後方散乱非対称係数	gb	-1 to -0.5	後方散乱の強さ
分配係数	k	0.8 to 1	前方/後方散乱の寄与比
ダスト/ガス明るさ比	δ90	1 to 10	ダスト散乱とガス放射の相対寄与

参考: EPSC-DPS2025-160

残差 (区間線形)

$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$

開始日 (UTC)	終了日 (UTC)	a	b
2019-12-04	2021-10-17	+97.4882	-24.758
2021-10-17	2023-02-09	-17.3894	+9.053

log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)

ファインディングチャート

天体暦

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-09-20 00:00	11:22:00.04	+03:13:39.4	HIP 55408	28.30
2026-09-20 12:00	11:22:30.54	+03:10:31.4	HIP 55408	31.69
2026-09-21 00:00	11:23:01.04	+03:07:23.2	HIP 55638	32.35
2026-09-21 12:00	11:23:31.56	+03:04:14.9	HIP 55638	33.29
2026-09-22 00:00	11:24:02.09	+03:01:06.4	HIP 55769	29.65
2026-09-22 12:00	11:24:32.62	+02:57:57.8	HIP 55769	26.13
2026-09-23 00:00	11:25:03.16	+02:54:49.0	HIP 55769	24.96
2026-09-23 12:00	11:25:33.70	+02:51:40.0	HIP 55846	20.15
2026-09-24 00:00	11:26:04.26	+02:48:30.9	HIP 55848	15.89
2026-09-24 12:00	11:26:34.82	+02:45:21.7	HIP 55848	15.28
2026-09-25 00:00	11:27:05.38	+02:42:12.3	HIP 55945	15.66
2026-09-25 12:00	11:27:35.95	+02:39:02.8	HIP 55945	13.33
2026-09-26 00:00	11:28:06.53	+02:35:53.2	HIP 55982	12.03
2026-09-26 12:00	11:28:37.10	+02:32:43.4	HIP 56029	12.77
2026-09-27 00:00	11:29:07.69	+02:29:33.5	HIP 56029	14.60
2026-09-27 12:00	11:29:38.28	+02:26:23.5	HIP 56029	20.00
2026-09-28 00:00	11:30:08.87	+02:23:13.4	HIP 56029	26.90
2026-09-28 12:00	11:30:39.46	+02:20:03.1	HIP 56029	34.41
2026-09-29 00:00	11:31:10.06	+02:16:52.8	HIP 56376	34.88
2026-09-29 12:00	11:31:40.66	+02:13:42.3	HIP 56376	29.13
2026-09-30 00:00	11:32:11.26	+02:10:31.8	HIP 56376	24.84
2026-09-30 12:00	11:32:41.87	+02:07:21.1	HIP 56376	22.87
2026-10-01 00:00	11:33:12.47	+02:04:10.4	HIP 56405	21.12
2026-10-01 12:00	11:33:43.08	+02:00:59.5	HIP 56405	15.93
2026-10-02 00:00	11:34:13.68	+01:57:48.6	HIP 56405	14.09
2026-10-02 12:00	11:34:44.29	+01:54:37.6	HIP 56405	16.75
2026-10-03 00:00	11:35:14.90	+01:51:26.5	HIP 56405	22.36
2026-10-03 12:00	11:35:45.50	+01:48:15.4	HIP 56681	24.93
2026-10-04 00:00	11:36:16.11	+01:45:04.2	HIP 56681	19.49
2026-10-04 12:00	11:36:46.71	+01:41:52.9	HIP 56681	16.60
2026-10-05 00:00	11:37:17.31	+01:38:41.6	HIP 56681	17.57
2026-10-05 12:00	11:37:47.91	+01:35:30.2	HIP 56755	20.79
2026-10-06 00:00	11:38:18.50	+01:32:18.7	HIP 56856	16.59
2026-10-06 12:00	11:38:49.09	+01:29:07.3	HIP 56856	9.64
2026-10-07 00:00	11:39:19.67	+01:25:55.8	HIP 56856	6.92
2026-10-07 12:00	11:39:50.25	+01:22:44.2	HIP 56856	11.83
2026-10-08 00:00	11:40:20.82	+01:19:32.6	HIP 56938	16.41
2026-10-08 12:00	11:40:51.39	+01:16:21.1	HIP 56941	20.40
2026-10-09 00:00	11:41:21.95	+01:13:09.5	HIP 57042	14.44
2026-10-09 12:00	11:41:52.50	+01:09:57.9	HIP 57042	10.67
2026-10-10 00:00	11:42:23.04	+01:06:46.3	HIP 57042	12.50
2026-10-10 12:00	11:42:53.58	+01:03:34.7	HIP 57042	18.32
2026-10-11 00:00	11:43:24.10	+01:00:23.1	HIP 57152	14.71