메타데이터
| 항목 |
값 |
| Designation |
C/2020 A2 (Iwamoto) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-01-08T07:41:43.028160Z |
| Orbit solution date (soln_date, UTC) |
2022-12-31T16:12:34Z |
| Obs used |
529 |
| NEO |
- |
| M1 |
15.100 |
| K1 |
10.750 |
| PC |
0.030 |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2020-02-23.0000000 |
| e |
0.99907770 |
| q (au) |
0.978012 |
| a (au) |
1060.410619 |
| i (deg) |
120.750132 |
| Ω (om, deg) |
286.379413 |
| ω (w, deg) |
68.209203 |
| M (ma, deg) |
0.001304 |
밝기
산란 + 전체 선형
$$
M_a = (11.896 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
11.896 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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 |
| 2020-01-08 |
2020-03-22 |
-3.5046 |
-0.515 |
| 2020-03-22 |
2020-04-15 |
+14.5888 |
-2.691 |
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 |
05:44:30.01 |
-11:54:16.6 |
HIP 26941 |
22.28 |
| 2026-09-20 12:00 |
05:44:29.48 |
-11:55:16.2 |
HIP 26941 |
22.39 |
| 2026-09-21 00:00 |
05:44:28.90 |
-11:56:15.8 |
HIP 26941 |
22.53 |
| 2026-09-21 12:00 |
05:44:28.26 |
-11:57:15.4 |
HIP 26941 |
22.70 |
| 2026-09-22 00:00 |
05:44:27.56 |
-11:58:15.1 |
HIP 26941 |
22.90 |
| 2026-09-22 12:00 |
05:44:26.82 |
-11:59:14.8 |
HIP 26941 |
23.14 |
| 2026-09-23 00:00 |
05:44:26.01 |
-12:00:14.5 |
HIP 26941 |
23.40 |
| 2026-09-23 12:00 |
05:44:25.16 |
-12:01:14.3 |
HIP 26941 |
23.69 |
| 2026-09-24 00:00 |
05:44:24.24 |
-12:02:14.0 |
HIP 26941 |
24.01 |
| 2026-09-24 12:00 |
05:44:23.28 |
-12:03:13.8 |
HIP 26941 |
24.36 |
| 2026-09-25 00:00 |
05:44:22.26 |
-12:04:13.5 |
HIP 26941 |
24.74 |
| 2026-09-25 12:00 |
05:44:21.18 |
-12:05:13.3 |
HIP 26941 |
25.14 |
| 2026-09-26 00:00 |
05:44:20.05 |
-12:06:13.1 |
HIP 27158 |
25.50 |
| 2026-09-26 12:00 |
05:44:18.87 |
-12:07:12.8 |
HIP 27158 |
24.92 |
| 2026-09-27 00:00 |
05:44:17.63 |
-12:08:12.6 |
HIP 27158 |
24.38 |
| 2026-09-27 12:00 |
05:44:16.33 |
-12:09:12.3 |
HIP 27158 |
23.89 |
| 2026-09-28 00:00 |
05:44:14.98 |
-12:10:12.0 |
HIP 27158 |
23.44 |
| 2026-09-28 12:00 |
05:44:13.58 |
-12:11:11.7 |
HIP 27158 |
23.04 |
| 2026-09-29 00:00 |
05:44:12.12 |
-12:12:11.4 |
HIP 27158 |
22.69 |
| 2026-09-29 12:00 |
05:44:10.60 |
-12:13:11.0 |
HIP 27158 |
22.39 |
| 2026-09-30 00:00 |
05:44:09.03 |
-12:14:10.6 |
HIP 27158 |
22.16 |
| 2026-09-30 12:00 |
05:44:07.41 |
-12:15:10.2 |
HIP 27158 |
21.99 |
| 2026-10-01 00:00 |
05:44:05.73 |
-12:16:09.7 |
HIP 27158 |
21.88 |
| 2026-10-01 12:00 |
05:44:04.00 |
-12:17:09.2 |
HIP 27158 |
21.83 |
| 2026-10-02 00:00 |
05:44:02.21 |
-12:18:08.7 |
HIP 27158 |
21.85 |
| 2026-10-02 12:00 |
05:44:00.37 |
-12:19:08.1 |
HIP 27158 |
21.94 |
| 2026-10-03 00:00 |
05:43:58.47 |
-12:20:07.4 |
HIP 27158 |
22.09 |
| 2026-10-03 12:00 |
05:43:56.52 |
-12:21:06.6 |
HIP 27158 |
22.31 |
| 2026-10-04 00:00 |
05:43:54.51 |
-12:22:05.8 |
HIP 27158 |
22.59 |
| 2026-10-04 12:00 |
05:43:52.45 |
-12:23:05.0 |
HIP 27158 |
22.94 |
| 2026-10-05 00:00 |
05:43:50.33 |
-12:24:04.0 |
HIP 27158 |
23.35 |
| 2026-10-05 12:00 |
05:43:48.16 |
-12:25:03.0 |
HIP 27158 |
23.81 |
| 2026-10-06 00:00 |
05:43:45.94 |
-12:26:01.9 |
HIP 27158 |
24.33 |
| 2026-10-06 12:00 |
05:43:43.66 |
-12:27:00.7 |
HIP 27089 |
23.82 |
| 2026-10-07 00:00 |
05:43:41.32 |
-12:27:59.4 |
HIP 27089 |
23.37 |
| 2026-10-07 12:00 |
05:43:38.93 |
-12:28:58.0 |
HIP 27089 |
22.96 |
| 2026-10-08 00:00 |
05:43:36.49 |
-12:29:56.6 |
HIP 27089 |
22.62 |
| 2026-10-08 12:00 |
05:43:33.99 |
-12:30:55.0 |
HIP 27089 |
22.35 |
| 2026-10-09 00:00 |
05:43:31.44 |
-12:31:53.3 |
HIP 27089 |
22.14 |
| 2026-10-09 12:00 |
05:43:28.83 |
-12:32:51.4 |
HIP 27089 |
22.00 |
| 2026-10-10 00:00 |
05:43:26.17 |
-12:33:49.5 |
HIP 27089 |
21.93 |
| 2026-10-10 12:00 |
05:43:23.46 |
-12:34:47.4 |
HIP 27089 |
21.93 |
| 2026-10-11 00:00 |
05:43:20.69 |
-12:35:45.2 |
HIP 27089 |
22.02 |