메타데이터
| 항목 |
값 |
| Designation |
C/2020 U4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-04-08T01:08:57.566400Z |
| Orbit solution date (soln_date, UTC) |
2024-10-05T23:12:23Z |
| Obs used |
921 |
| NEO |
- |
| M1 |
5.700 |
| K1 |
12.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-10-22T13:20:36.067200Z |
| Discovery magnitude (MPC) |
20.20 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2022-05-31.0000000 |
| e |
1.00130917 |
| q (au) |
5.353691 |
| a (au) |
-4089.389408 |
| i (deg) |
167.035866 |
| Ω (om, deg) |
120.013777 |
| ω (w, deg) |
69.541084 |
| M (ma, deg) |
0.000200 |
밝기
산란 + 전체 선형
$$
M_a = (8.338 + 5.142\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
8.338 |
| n |
5.142 |
| gf |
0.996 |
| gb |
-0.733 |
| k |
0.800 |
| δ90 |
9.288 |
| 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 |
| 2019-11-09 |
2021-01-18 |
+7.7107 |
-6.501 |
| 2021-01-18 |
2022-03-24 |
-6.4323 |
+4.665 |
| 2022-07-24 |
2024-09-11 |
-0.0039 |
+0.097 |
log10 r = log10(태양거리/AU), Δ = 지구거리(AU)
천체력
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
21:07:06.79 |
-12:51:15.4 |
HIP 104343 |
16.81 |
| 2026-07-29 12:00 |
21:06:53.60 |
-12:52:22.8 |
HIP 104343 |
19.96 |
| 2026-07-30 00:00 |
21:06:40.40 |
-12:53:30.3 |
HIP 104343 |
23.18 |
| 2026-07-30 12:00 |
21:06:27.19 |
-12:54:37.8 |
HIP 104343 |
26.45 |
| 2026-07-31 00:00 |
21:06:13.96 |
-12:55:45.5 |
HIP 104343 |
29.75 |
| 2026-07-31 12:00 |
21:06:00.73 |
-12:56:53.2 |
HIP 104343 |
33.08 |
| 2026-08-01 00:00 |
21:05:47.50 |
-12:58:01.0 |
HIP 103942 |
32.56 |
| 2026-08-01 12:00 |
21:05:34.25 |
-12:59:08.8 |
HIP 103942 |
29.70 |
| 2026-08-02 00:00 |
21:05:21.00 |
-13:00:16.7 |
HIP 103942 |
26.98 |
| 2026-08-02 12:00 |
21:05:07.75 |
-13:01:24.7 |
HIP 103942 |
24.44 |
| 2026-08-03 00:00 |
21:04:54.49 |
-13:02:32.7 |
HIP 103942 |
22.13 |
| 2026-08-03 12:00 |
21:04:41.23 |
-13:03:40.8 |
HIP 103942 |
20.14 |
| 2026-08-04 00:00 |
21:04:27.97 |
-13:04:48.9 |
HIP 103942 |
18.58 |
| 2026-08-04 12:00 |
21:04:14.70 |
-13:05:57.0 |
HIP 103942 |
17.55 |
| 2026-08-05 00:00 |
21:04:01.44 |
-13:07:05.2 |
HIP 103942 |
17.16 |
| 2026-08-05 12:00 |
21:03:48.18 |
-13:08:13.3 |
HIP 103942 |
17.45 |
| 2026-08-06 00:00 |
21:03:34.92 |
-13:09:21.6 |
HIP 103942 |
18.38 |
| 2026-08-06 12:00 |
21:03:21.66 |
-13:10:29.8 |
HIP 103942 |
19.87 |
| 2026-08-07 00:00 |
21:03:08.41 |
-13:11:38.0 |
HIP 103942 |
21.80 |
| 2026-08-07 12:00 |
21:02:55.16 |
-13:12:46.3 |
HIP 103942 |
24.06 |
| 2026-08-08 00:00 |
21:02:41.92 |
-13:13:54.5 |
HIP 103771 |
22.11 |
| 2026-08-08 12:00 |
21:02:28.68 |
-13:15:02.8 |
HIP 103771 |
19.20 |
| 2026-08-09 00:00 |
21:02:15.46 |
-13:16:11.0 |
HIP 103771 |
16.49 |
| 2026-08-09 12:00 |
21:02:02.24 |
-13:17:19.2 |
HIP 103771 |
14.08 |
| 2026-08-10 00:00 |
21:01:49.03 |
-13:18:27.4 |
HIP 103771 |
12.15 |
| 2026-08-10 12:00 |
21:01:35.84 |
-13:19:35.6 |
HIP 103771 |
10.98 |
| 2026-08-11 00:00 |
21:01:22.66 |
-13:20:43.8 |
HIP 103771 |
10.80 |
| 2026-08-11 12:00 |
21:01:09.49 |
-13:21:51.9 |
HIP 103728 |
9.94 |
| 2026-08-12 00:00 |
21:00:56.34 |
-13:23:00.0 |
HIP 103672 |
9.00 |
| 2026-08-12 12:00 |
21:00:43.20 |
-13:24:08.1 |
HIP 103672 |
6.70 |
| 2026-08-13 00:00 |
21:00:30.08 |
-13:25:16.1 |
HIP 103672 |
5.63 |
| 2026-08-13 12:00 |
21:00:16.98 |
-13:26:24.0 |
HIP 103665 |
3.56 |
| 2026-08-14 00:00 |
21:00:03.89 |
-13:27:32.0 |
HIP 103665 |
3.52 |
| 2026-08-14 12:00 |
20:59:50.83 |
-13:28:39.8 |
HIP 103665 |
5.90 |
| 2026-08-15 00:00 |
20:59:37.79 |
-13:29:47.6 |
HIP 103665 |
8.94 |
| 2026-08-15 12:00 |
20:59:24.77 |
-13:30:55.3 |
HIP 103665 |
12.14 |
| 2026-08-16 00:00 |
20:59:11.78 |
-13:32:02.9 |
HIP 103665 |
15.41 |
| 2026-08-16 12:00 |
20:58:58.80 |
-13:33:10.4 |
HIP 103665 |
18.70 |
| 2026-08-17 00:00 |
20:58:45.86 |
-13:34:17.9 |
HIP 103574 |
21.88 |
| 2026-08-17 12:00 |
20:58:32.94 |
-13:35:25.3 |
HIP 103574 |
23.82 |
| 2026-08-18 00:00 |
20:58:20.05 |
-13:36:32.5 |
HIP 103574 |
26.05 |
| 2026-08-18 12:00 |
20:58:07.19 |
-13:37:39.7 |
HIP 103574 |
28.48 |
| 2026-08-19 00:00 |
20:57:54.35 |
-13:38:46.8 |
HIP 103337 |
26.64 |