메타데이터
| 항목 |
값 |
| Designation |
C/2021 P4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-07-30T09:00:29.151360Z |
| Orbit solution date (soln_date, UTC) |
2024-07-30T14:57:24Z |
| Obs used |
954 |
| NEO |
- |
| M1 |
10.800 |
| K1 |
8.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-08-10T12:53:31.315200Z |
| Discovery magnitude (MPC) |
19.44 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2022-01-11.0000000 |
| e |
0.99656560 |
| q (au) |
1.080462 |
| a (au) |
314.600427 |
| i (deg) |
56.310801 |
| Ω (om, deg) |
348.094879 |
| ω (w, deg) |
175.822404 |
| M (ma, deg) |
359.964608 |
밝기
산란 + 전체 선형
$$
M_a = (9.844 + 3.192\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
9.844 |
| n |
3.192 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
7.364 |
| 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 |
| 2021-08-10 |
2022-05-06 |
+2.3133 |
-1.380 |
| 2022-05-06 |
2022-06-13 |
-2.7477 |
+0.128 |
| 2022-06-13 |
2022-07-22 |
+21.5568 |
-2.643 |
log10 r = log10(태양거리/AU), Δ = 지구거리(AU)
천체력
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
22:49:44.99 |
-39:23:58.4 |
HIP 112672 |
12.12 |
| 2026-03-26 12:00 |
22:49:55.22 |
-39:23:33.3 |
HIP 112672 |
13.84 |
| 2026-03-27 00:00 |
22:50:05.42 |
-39:23:08.9 |
HIP 112672 |
15.62 |
| 2026-03-27 12:00 |
22:50:15.57 |
-39:22:45.1 |
HIP 112832 |
16.10 |
| 2026-03-28 00:00 |
22:50:25.68 |
-39:22:22.0 |
HIP 112832 |
14.75 |
| 2026-03-28 12:00 |
22:50:35.76 |
-39:21:59.5 |
HIP 112832 |
13.58 |
| 2026-03-29 00:00 |
22:50:45.79 |
-39:21:37.7 |
HIP 112832 |
12.62 |
| 2026-03-29 12:00 |
22:50:55.78 |
-39:21:16.6 |
HIP 112832 |
11.93 |
| 2026-03-30 00:00 |
22:51:05.72 |
-39:20:56.2 |
HIP 112832 |
11.55 |
| 2026-03-30 12:00 |
22:51:15.62 |
-39:20:36.4 |
HIP 112832 |
11.50 |
| 2026-03-31 00:00 |
22:51:25.48 |
-39:20:17.3 |
HIP 112832 |
11.78 |
| 2026-03-31 12:00 |
22:51:35.30 |
-39:19:58.9 |
HIP 112938 |
10.00 |
| 2026-04-01 00:00 |
22:51:45.07 |
-39:19:41.1 |
HIP 112938 |
8.09 |
| 2026-04-01 12:00 |
22:51:54.80 |
-39:19:24.1 |
HIP 112938 |
6.19 |
| 2026-04-02 00:00 |
22:52:04.48 |
-39:19:07.7 |
HIP 112938 |
4.31 |
| 2026-04-02 12:00 |
22:52:14.11 |
-39:18:51.9 |
HIP 112938 |
2.45 |
| 2026-04-03 00:00 |
22:52:23.70 |
-39:18:36.9 |
HIP 112938 |
0.74 |
| 2026-04-03 12:00 |
22:52:33.24 |
-39:18:22.5 |
HIP 112938 |
1.44 |
| 2026-04-04 00:00 |
22:52:42.74 |
-39:18:08.8 |
HIP 112938 |
3.24 |
| 2026-04-04 12:00 |
22:52:52.18 |
-39:17:55.8 |
HIP 112938 |
5.06 |
| 2026-04-05 00:00 |
22:53:01.58 |
-39:17:43.4 |
HIP 112938 |
6.89 |
| 2026-04-05 12:00 |
22:53:10.93 |
-39:17:31.8 |
HIP 113034 |
8.56 |
| 2026-04-06 00:00 |
22:53:20.23 |
-39:17:20.8 |
HIP 113034 |
8.10 |
| 2026-04-06 12:00 |
22:53:29.48 |
-39:17:10.5 |
HIP 113034 |
8.02 |
| 2026-04-07 00:00 |
22:53:38.68 |
-39:17:00.9 |
HIP 113034 |
8.33 |
| 2026-04-07 12:00 |
22:53:47.83 |
-39:16:51.9 |
HIP 113034 |
8.97 |
| 2026-04-08 00:00 |
22:53:56.93 |
-39:16:43.7 |
HIP 113034 |
9.88 |
| 2026-04-08 12:00 |
22:54:05.98 |
-39:16:36.1 |
HIP 113034 |
10.99 |
| 2026-04-09 00:00 |
22:54:14.97 |
-39:16:29.2 |
HIP 113034 |
12.23 |
| 2026-04-09 12:00 |
22:54:23.92 |
-39:16:23.0 |
HIP 113034 |
13.56 |
| 2026-04-10 00:00 |
22:54:32.81 |
-39:16:17.5 |
HIP 113034 |
14.97 |
| 2026-04-10 12:00 |
22:54:41.64 |
-39:16:12.7 |
HIP 113034 |
16.42 |
| 2026-04-11 00:00 |
22:54:50.42 |
-39:16:08.6 |
HIP 113034 |
17.90 |
| 2026-04-11 12:00 |
22:54:59.15 |
-39:16:05.1 |
HIP 113034 |
19.40 |
| 2026-04-12 00:00 |
22:55:07.82 |
-39:16:02.3 |
HIP 113034 |
20.91 |
| 2026-04-12 12:00 |
22:55:16.43 |
-39:16:00.3 |
HIP 113034 |
22.43 |
| 2026-04-13 00:00 |
22:55:24.99 |
-39:15:58.9 |
HIP 113034 |
23.96 |
| 2026-04-13 12:00 |
22:55:33.49 |
-39:15:58.2 |
HIP 113034 |
25.49 |
| 2026-04-14 00:00 |
22:55:41.94 |
-39:15:58.2 |
HIP 113034 |
27.02 |
| 2026-04-14 12:00 |
22:55:50.32 |
-39:15:58.9 |
HIP 113034 |
28.55 |
| 2026-04-15 00:00 |
22:55:58.65 |
-39:16:00.3 |
HIP 113034 |
30.07 |
| 2026-04-15 12:00 |
22:56:06.92 |
-39:16:02.3 |
HIP 113034 |
31.58 |
| 2026-04-16 00:00 |
22:56:15.13 |
-39:16:05.1 |
HIP 113034 |
33.09 |