메타데이터
| 항목 |
값 |
| Designation |
C/2021 A7 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-07-15T07:52:29.438400Z |
| Orbit solution date (soln_date, UTC) |
2022-06-28T01:12:46Z |
| Obs used |
295 |
| NEO |
- |
| M1 |
11.600 |
| K1 |
9.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-01-09T02:37:24.384000Z |
| Discovery magnitude (MPC) |
20.00 R |
| Discovery observatory (MPC) |
C51 · WISE |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2021-04-15.0000000 |
| e |
0.99972271 |
| q (au) |
1.967689 |
| a (au) |
7096.234707 |
| i (deg) |
78.149198 |
| Ω (om, deg) |
154.518746 |
| ω (w, deg) |
356.065440 |
| M (ma, deg) |
359.999849 |
밝기
산란 + 전체 선형
$$
M_a = (11.691 + 4.023\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
11.691 |
| n |
4.023 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
0.800 |
| 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 |
| 2021-01-09 |
2021-07-08 |
-0.1334 |
-0.114 |
| 2021-11-10 |
2022-06-25 |
-4.5628 |
+3.915 |
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 |
20:48:37.27 |
+28:44:04.8 |
HIP 102786 |
11.62 |
| 2026-03-26 12:00 |
20:48:43.04 |
+28:45:16.9 |
HIP 102786 |
10.98 |
| 2026-03-27 00:00 |
20:48:48.76 |
+28:46:29.4 |
HIP 102786 |
10.61 |
| 2026-03-27 12:00 |
20:48:54.41 |
+28:47:42.1 |
HIP 102786 |
10.53 |
| 2026-03-28 00:00 |
20:49:00.00 |
+28:48:55.0 |
HIP 102786 |
10.74 |
| 2026-03-28 12:00 |
20:49:05.53 |
+28:50:08.2 |
HIP 102786 |
11.23 |
| 2026-03-29 00:00 |
20:49:11.00 |
+28:51:21.6 |
HIP 102786 |
11.96 |
| 2026-03-29 12:00 |
20:49:16.41 |
+28:52:35.2 |
HIP 102786 |
12.88 |
| 2026-03-30 00:00 |
20:49:21.75 |
+28:53:49.1 |
HIP 102786 |
13.95 |
| 2026-03-30 12:00 |
20:49:27.03 |
+28:55:03.2 |
HIP 102786 |
15.14 |
| 2026-03-31 00:00 |
20:49:32.24 |
+28:56:17.5 |
HIP 102786 |
16.42 |
| 2026-03-31 12:00 |
20:49:37.40 |
+28:57:32.0 |
HIP 102786 |
17.78 |
| 2026-04-01 00:00 |
20:49:42.48 |
+28:58:46.7 |
HIP 102786 |
19.18 |
| 2026-04-01 12:00 |
20:49:47.51 |
+29:00:01.7 |
HIP 102786 |
20.62 |
| 2026-04-02 00:00 |
20:49:52.47 |
+29:01:16.8 |
HIP 102786 |
22.10 |
| 2026-04-02 12:00 |
20:49:57.36 |
+29:02:32.1 |
HIP 102851 |
20.72 |
| 2026-04-03 00:00 |
20:50:02.19 |
+29:03:47.6 |
HIP 102851 |
19.35 |
| 2026-04-03 12:00 |
20:50:06.96 |
+29:05:03.3 |
HIP 102851 |
18.02 |
| 2026-04-04 00:00 |
20:50:11.66 |
+29:06:19.2 |
HIP 102851 |
16.74 |
| 2026-04-04 12:00 |
20:50:16.29 |
+29:07:35.2 |
HIP 102851 |
15.52 |
| 2026-04-05 00:00 |
20:50:20.86 |
+29:08:51.4 |
HIP 102851 |
14.38 |
| 2026-04-05 12:00 |
20:50:25.36 |
+29:10:07.7 |
HIP 102851 |
13.32 |
| 2026-04-06 00:00 |
20:50:29.79 |
+29:11:24.3 |
HIP 102851 |
12.38 |
| 2026-04-06 12:00 |
20:50:34.16 |
+29:12:40.9 |
HIP 102851 |
11.58 |
| 2026-04-07 00:00 |
20:50:38.46 |
+29:13:57.7 |
HIP 102851 |
10.94 |
| 2026-04-07 12:00 |
20:50:42.69 |
+29:15:14.7 |
HIP 102851 |
10.49 |
| 2026-04-08 00:00 |
20:50:46.85 |
+29:16:31.7 |
HIP 102851 |
10.26 |
| 2026-04-08 12:00 |
20:50:50.95 |
+29:17:48.9 |
HIP 102851 |
10.25 |
| 2026-04-09 00:00 |
20:50:54.98 |
+29:19:06.2 |
HIP 102851 |
10.46 |
| 2026-04-09 12:00 |
20:50:58.93 |
+29:20:23.7 |
HIP 102851 |
10.87 |
| 2026-04-10 00:00 |
20:51:02.82 |
+29:21:41.2 |
HIP 102851 |
11.47 |
| 2026-04-10 12:00 |
20:51:06.64 |
+29:22:58.9 |
HIP 102851 |
12.22 |
| 2026-04-11 00:00 |
20:51:10.39 |
+29:24:16.6 |
HIP 102851 |
13.09 |
| 2026-04-11 12:00 |
20:51:14.07 |
+29:25:34.5 |
HIP 102851 |
14.06 |
| 2026-04-12 00:00 |
20:51:17.68 |
+29:26:52.4 |
HIP 102851 |
15.11 |
| 2026-04-12 12:00 |
20:51:21.22 |
+29:28:10.4 |
HIP 102851 |
16.22 |
| 2026-04-13 00:00 |
20:51:24.69 |
+29:29:28.5 |
HIP 102851 |
17.37 |
| 2026-04-13 12:00 |
20:51:28.09 |
+29:30:46.7 |
HIP 102851 |
18.56 |
| 2026-04-14 00:00 |
20:51:31.41 |
+29:32:04.9 |
HIP 102896 |
19.17 |
| 2026-04-14 12:00 |
20:51:34.67 |
+29:33:23.2 |
HIP 102896 |
18.50 |
| 2026-04-15 00:00 |
20:51:37.85 |
+29:34:41.5 |
HIP 102896 |
17.92 |
| 2026-04-15 12:00 |
20:51:40.96 |
+29:35:59.8 |
HIP 102896 |
17.43 |
| 2026-04-16 00:00 |
20:51:43.99 |
+29:37:18.3 |
HIP 102896 |
17.04 |