메타데이터
| 항목 |
값 |
| Designation |
C/2021 A2 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-01-22T15:13:06.119040Z |
| Orbit solution date (soln_date, UTC) |
2025-01-02T20:12:26Z |
| Obs used |
980 |
| NEO |
- |
| M1 |
15.000 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-03T00:31:00.192000Z |
| Discovery magnitude (MPC) |
15.00 R |
| Discovery observatory (MPC) |
C51 · WISE |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2021-02-20.0000000 |
| e |
0.99451672 |
| q (au) |
1.412974 |
| a (au) |
257.687917 |
| i (deg) |
106.978275 |
| Ω (om, deg) |
125.238283 |
| ω (w, deg) |
338.849015 |
| M (ma, deg) |
0.006759 |
밝기
산란 + 전체 선형
$$
M_a = (14.158 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
14.158 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.991 |
| 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 |
| 2021-01-23 |
2021-05-09 |
+4.2062 |
-1.270 |
log10 r = log10(태양거리/AU), Δ = 지구거리(AU)
천체력
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
20:57:43.08 |
+38:25:18.3 |
HIP 103540 |
19.68 |
| 2026-06-01 12:00 |
20:57:38.53 |
+38:26:18.1 |
HIP 103540 |
21.00 |
| 2026-06-02 00:00 |
20:57:33.91 |
+38:27:17.5 |
HIP 103540 |
22.33 |
| 2026-06-02 12:00 |
20:57:29.22 |
+38:28:16.3 |
HIP 103540 |
23.66 |
| 2026-06-03 00:00 |
20:57:24.46 |
+38:29:14.7 |
HIP 103540 |
25.00 |
| 2026-06-03 12:00 |
20:57:19.63 |
+38:30:12.5 |
HIP 103331 |
25.54 |
| 2026-06-04 00:00 |
20:57:14.73 |
+38:31:09.8 |
HIP 103331 |
24.21 |
| 2026-06-04 12:00 |
20:57:09.75 |
+38:32:06.6 |
HIP 103331 |
22.88 |
| 2026-06-05 00:00 |
20:57:04.71 |
+38:33:02.9 |
HIP 103331 |
21.55 |
| 2026-06-05 12:00 |
20:56:59.60 |
+38:33:58.6 |
HIP 103331 |
20.22 |
| 2026-06-06 00:00 |
20:56:54.42 |
+38:34:53.8 |
HIP 103331 |
18.90 |
| 2026-06-06 12:00 |
20:56:49.18 |
+38:35:48.4 |
HIP 103331 |
17.59 |
| 2026-06-07 00:00 |
20:56:43.86 |
+38:36:42.5 |
HIP 103331 |
16.30 |
| 2026-06-07 12:00 |
20:56:38.48 |
+38:37:36.0 |
HIP 103331 |
15.01 |
| 2026-06-08 00:00 |
20:56:33.02 |
+38:38:29.0 |
HIP 103331 |
13.75 |
| 2026-06-08 12:00 |
20:56:27.50 |
+38:39:21.4 |
HIP 103331 |
12.52 |
| 2026-06-09 00:00 |
20:56:21.92 |
+38:40:13.2 |
HIP 103331 |
11.33 |
| 2026-06-09 12:00 |
20:56:16.26 |
+38:41:04.4 |
HIP 103331 |
10.19 |
| 2026-06-10 00:00 |
20:56:10.54 |
+38:41:55.1 |
HIP 103331 |
9.14 |
| 2026-06-10 12:00 |
20:56:04.76 |
+38:42:45.1 |
HIP 103331 |
8.19 |
| 2026-06-11 00:00 |
20:55:58.91 |
+38:43:34.6 |
HIP 103331 |
7.41 |
| 2026-06-11 12:00 |
20:55:52.99 |
+38:44:23.4 |
HIP 103331 |
6.84 |
| 2026-06-12 00:00 |
20:55:47.01 |
+38:45:11.7 |
HIP 103331 |
6.55 |
| 2026-06-12 12:00 |
20:55:40.96 |
+38:45:59.3 |
HIP 103331 |
6.57 |
| 2026-06-13 00:00 |
20:55:34.85 |
+38:46:46.3 |
HIP 103331 |
6.91 |
| 2026-06-13 12:00 |
20:55:28.68 |
+38:47:32.7 |
HIP 103295 |
6.78 |
| 2026-06-14 00:00 |
20:55:22.44 |
+38:48:18.4 |
HIP 103295 |
6.47 |
| 2026-06-14 12:00 |
20:55:16.14 |
+38:49:03.5 |
HIP 103295 |
6.48 |
| 2026-06-15 00:00 |
20:55:09.78 |
+38:49:47.9 |
HIP 103295 |
6.81 |
| 2026-06-15 12:00 |
20:55:03.35 |
+38:50:31.7 |
HIP 103295 |
7.44 |
| 2026-06-16 00:00 |
20:54:56.87 |
+38:51:14.9 |
HIP 103295 |
8.28 |
| 2026-06-16 12:00 |
20:54:50.32 |
+38:51:57.4 |
HIP 103295 |
9.30 |
| 2026-06-17 00:00 |
20:54:43.71 |
+38:52:39.2 |
HIP 103295 |
10.43 |
| 2026-06-17 12:00 |
20:54:37.05 |
+38:53:20.3 |
HIP 103295 |
11.64 |
| 2026-06-18 00:00 |
20:54:30.32 |
+38:54:00.8 |
HIP 103295 |
12.92 |
| 2026-06-18 12:00 |
20:54:23.53 |
+38:54:40.6 |
HIP 103295 |
14.25 |
| 2026-06-19 00:00 |
20:54:16.69 |
+38:55:19.7 |
HIP 103295 |
15.62 |
| 2026-06-19 12:00 |
20:54:09.79 |
+38:55:58.1 |
HIP 103295 |
17.01 |
| 2026-06-20 00:00 |
20:54:02.83 |
+38:56:35.8 |
HIP 103051 |
17.55 |
| 2026-06-20 12:00 |
20:53:55.82 |
+38:57:12.8 |
HIP 103051 |
16.67 |
| 2026-06-21 00:00 |
20:53:48.75 |
+38:57:49.2 |
HIP 103051 |
15.88 |
| 2026-06-21 12:00 |
20:53:41.62 |
+38:58:24.8 |
HIP 103051 |
15.17 |
| 2026-06-22 00:00 |
20:53:34.44 |
+38:58:59.7 |
HIP 103051 |
14.58 |