메타데이터

항목	값
Designation	78P/Gehrels 2
Type	P
Perihelion (tp_cal, UTC)	2019-04-03T05:24:15.050880Z
Orbit solution date (soln_date, UTC)	2026-03-07T15:22:14Z
Obs used	6064
NEO	-
M1	9.100
K1	13.250
PC	0.030

Osculating 궤도요소

항목	값
Epoch (epoch_cal, TDB)	2016-01-21.0000000
e	0.46118333
q (au)	2.013818
a (au)	3.737483
i (deg)	6.250321
Ω (om, deg)	210.558992
ω (w, deg)	192.733774
M (ma, deg)	200.646435

밝기

산란 + 전체 선형

$$ M_a = (7.453 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

모델 상수

항목	값
H0	7.453
n	6.000
gf	1.000
gb	-1.000
k	1.000
δ90	10.000

파라미터	기호	범위	설명
태양·지구거리 1 AU에서의 절대등급	H0	-5 to 20	혜성의 고유 밝기
광도 기울기 파라미터	n	2 to 6	태양거리 변화에 따른 밝기 변화율
전방 산란 비대칭 계수	gf	0.8 to 1	전방 산란의 강도
후방 산란 비대칭 계수	gb	-1 to -0.5	후방 산란의 강도
분할 계수	k	0.8 to 1	전·후방 산란 기여도 비율
먼지/가스 밝기 비	δ90	1 to 10	코마에서 먼지 산란 대비 가스 방출의 상대 기여

참고: EPSC-DPS2025-160

잔차 (구간 선형)

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

시작일 (UTC)	끝 (UTC)	a	b
2025-04-25	2025-10-23	-5.9460	+2.177
2025-10-23	2026-01-12	+4.4137	-2.105

log10 r = log10(태양거리/AU), Δ = 지구거리(AU)

찾아보기

천체력

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-03-26 00:00	00:20:04.12	+04:02:48.1	HIP 1455	32.64
2026-03-26 12:00	00:21:07.81	+04:08:48.2	HIP 1628	39.64
2026-03-27 00:00	00:22:11.56	+04:14:48.4	HIP 1894	39.26
2026-03-27 12:00	00:23:15.37	+04:20:48.6	HIP 1894	36.65
2026-03-28 00:00	00:24:19.24	+04:26:48.9	HIP 2046	39.60
2026-03-28 12:00	00:25:23.18	+04:32:49.2	HIP 2195	35.14
2026-03-29 00:00	00:26:27.18	+04:38:49.5	HIP 2195	19.16
2026-03-29 12:00	00:27:31.24	+04:44:49.9	HIP 2195	8.94
2026-03-30 00:00	00:28:35.36	+04:50:50.3	HIP 2195	19.36
2026-03-30 12:00	00:29:39.55	+04:56:50.7	HIP 2358	8.95
2026-03-31 00:00	00:30:43.80	+05:02:51.0	HIP 2358	14.24
2026-03-31 12:00	00:31:48.11	+05:08:51.4	HIP 2510	18.09
2026-04-01 00:00	00:32:52.49	+05:14:51.7	HIP 2659	21.66
2026-04-01 12:00	00:33:56.94	+05:20:52.0	HIP 2659	24.33
2026-04-02 00:00	00:35:01.44	+05:26:52.2	HIP 2918	28.86
2026-04-02 12:00	00:36:06.01	+05:32:52.3	HIP 2918	15.08
2026-04-03 00:00	00:37:10.65	+05:38:52.4	HIP 2918	14.52
2026-04-03 12:00	00:38:15.35	+05:44:52.3	HIP 2991	6.93
2026-04-04 00:00	00:39:20.12	+05:50:52.2	HIP 3033	15.44
2026-04-04 12:00	00:40:24.95	+05:56:51.9	HIP 3033	27.84
2026-04-05 00:00	00:41:29.84	+06:02:51.5	HIP 3338	27.28
2026-04-05 12:00	00:42:34.81	+06:08:51.0	HIP 3393	27.36
2026-04-06 00:00	00:43:39.83	+06:14:50.3	HIP 3393	20.21
2026-04-06 12:00	00:44:44.93	+06:20:49.5	HIP 3393	25.74
2026-04-07 00:00	00:45:50.09	+06:26:48.4	HIP 3697	29.17
2026-04-07 12:00	00:46:55.32	+06:32:47.2	HIP 3697	13.62
2026-04-08 00:00	00:48:00.61	+06:38:45.8	HIP 3697	10.81
2026-04-08 12:00	00:49:05.97	+06:44:44.2	HIP 3869	21.99
2026-04-09 00:00	00:50:11.40	+06:50:42.3	HIP 3972	13.41
2026-04-09 12:00	00:51:16.89	+06:56:40.2	HIP 3972	4.22
2026-04-10 00:00	00:52:22.45	+07:02:37.8	HIP 4067	14.81
2026-04-10 12:00	00:53:28.08	+07:08:35.2	HIP 4219	9.35
2026-04-11 00:00	00:54:33.77	+07:14:32.3	HIP 4219	11.13
2026-04-11 12:00	00:55:39.53	+07:20:29.1	HIP 4445	18.88
2026-04-12 00:00	00:56:45.36	+07:26:25.6	HIP 4445	2.71
2026-04-12 12:00	00:57:51.26	+07:32:21.8	HIP 4526	4.69
2026-04-13 00:00	00:58:57.22	+07:38:17.6	HIP 4601	4.88
2026-04-13 12:00	01:00:03.25	+07:44:13.1	HIP 4601	16.03
2026-04-14 00:00	01:01:09.35	+07:50:08.2	HIP 4763	11.92
2026-04-14 12:00	01:02:15.51	+07:56:02.9	HIP 4832	2.18
2026-04-15 00:00	01:03:21.74	+08:01:57.3	HIP 4906	10.57
2026-04-15 12:00	01:04:28.04	+08:07:51.2	HIP 5103	18.39
2026-04-16 00:00	01:05:34.41	+08:13:44.7	HIP 5103	6.68