메타데이터

항목	값
Designation	C/2012 S1 (ISON)
Type	C
Perihelion (tp_cal, UTC)	2013-11-28T18:20:55.495680Z
Orbit solution date (soln_date, UTC)	2025-11-21T13:42:48Z
Obs used	6684
NEO	-
M1	10.400
K1	4.500
PC	-

Osculating 궤도요소

항목	값
Epoch (epoch_cal, TDB)	2013-05-01.0000000
e	1.00000509
q (au)	0.012467
a (au)	-2446.893404
i (deg)	62.162896
Ω (om, deg)	295.686541
ω (w, deg)	345.541197
M (ma, deg)	-0.001724

밝기

산란 + 전체 선형

$$ M_a = (11.695 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

모델 상수

항목	값
H0	11.695
n	2.000
gf	1.000
gb	-0.791
k	0.951
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
2011-09-30	2013-11-13	+0.7784	-0.530
2013-11-13	2013-11-28	+7.8926	-0.124

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

천체력

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-09-20 00:00	07:33:54.85	+36:40:46.5	HIP 36704	23.65
2026-09-20 12:00	07:33:56.61	+36:40:55.8	HIP 36704	23.68
2026-09-21 00:00	07:33:58.34	+36:41:05.2	HIP 36704	23.70
2026-09-21 12:00	07:34:00.03	+36:41:14.7	HIP 36704	23.73
2026-09-22 00:00	07:34:01.69	+36:41:24.3	HIP 36704	23.76
2026-09-22 12:00	07:34:03.31	+36:41:34.0	HIP 36704	23.79
2026-09-23 00:00	07:34:04.90	+36:41:43.9	HIP 36704	23.83
2026-09-23 12:00	07:34:06.46	+36:41:53.8	HIP 36704	23.86
2026-09-24 00:00	07:34:07.98	+36:42:03.9	HIP 36704	23.89
2026-09-24 12:00	07:34:09.46	+36:42:14.0	HIP 36704	23.92
2026-09-25 00:00	07:34:10.92	+36:42:24.3	HIP 36704	23.95
2026-09-25 12:00	07:34:12.33	+36:42:34.7	HIP 36704	23.97
2026-09-26 00:00	07:34:13.71	+36:42:45.2	HIP 36704	24.00
2026-09-26 12:00	07:34:15.06	+36:42:55.8	HIP 36704	24.03
2026-09-27 00:00	07:34:16.37	+36:43:06.5	HIP 36704	24.05
2026-09-27 12:00	07:34:17.65	+36:43:17.4	HIP 36704	24.07
2026-09-28 00:00	07:34:18.89	+36:43:28.3	HIP 36704	24.09
2026-09-28 12:00	07:34:20.09	+36:43:39.3	HIP 36704	24.11
2026-09-29 00:00	07:34:21.26	+36:43:50.5	HIP 36704	24.13
2026-09-29 12:00	07:34:22.39	+36:44:01.7	HIP 36704	24.14
2026-09-30 00:00	07:34:23.49	+36:44:13.1	HIP 36704	24.15
2026-09-30 12:00	07:34:24.55	+36:44:24.5	HIP 36704	24.16
2026-10-01 00:00	07:34:25.58	+36:44:36.1	HIP 36704	24.17
2026-10-01 12:00	07:34:26.56	+36:44:47.7	HIP 36704	24.17
2026-10-02 00:00	07:34:27.52	+36:44:59.5	HIP 36704	24.17
2026-10-02 12:00	07:34:28.43	+36:45:11.4	HIP 36704	24.16
2026-10-03 00:00	07:34:29.31	+36:45:23.3	HIP 36704	24.15
2026-10-03 12:00	07:34:30.15	+36:45:35.4	HIP 36704	24.14
2026-10-04 00:00	07:34:30.95	+36:45:47.6	HIP 36704	24.13
2026-10-04 12:00	07:34:31.72	+36:45:59.8	HIP 36704	24.11
2026-10-05 00:00	07:34:32.45	+36:46:12.2	HIP 36704	24.08
2026-10-05 12:00	07:34:33.14	+36:46:24.7	HIP 36704	24.05
2026-10-06 00:00	07:34:33.80	+36:46:37.2	HIP 36704	24.02
2026-10-06 12:00	07:34:34.41	+36:46:49.9	HIP 36704	23.99
2026-10-07 00:00	07:34:34.99	+36:47:02.6	HIP 36704	23.94
2026-10-07 12:00	07:34:35.53	+36:47:15.5	HIP 36704	23.90
2026-10-08 00:00	07:34:36.04	+36:47:28.4	HIP 36704	23.85
2026-10-08 12:00	07:34:36.50	+36:47:41.5	HIP 36704	23.79
2026-10-09 00:00	07:34:36.93	+36:47:54.6	HIP 36704	23.73
2026-10-09 12:00	07:34:37.32	+36:48:07.8	HIP 36704	23.67
2026-10-10 00:00	07:34:37.67	+36:48:21.1	HIP 36704	23.60
2026-10-10 12:00	07:34:37.98	+36:48:34.5	HIP 36704	23.52
2026-10-11 00:00	07:34:38.25	+36:48:48.0	HIP 36704	23.44