C/2021 A7 (NEOWISE)
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) |
| 2026-02-03 00:00 |
20:34:41.41 |
+27:19:08.0 |
HIP 101428 |
20.25 |
| 2026-02-03 12:00 |
20:34:51.19 |
+27:19:28.8 |
HIP 101604 |
21.19 |
| 2026-02-04 00:00 |
20:35:00.96 |
+27:19:50.4 |
HIP 101604 |
20.09 |
| 2026-02-04 12:00 |
20:35:10.71 |
+27:20:12.7 |
HIP 101604 |
19.16 |
| 2026-02-05 00:00 |
20:35:20.45 |
+27:20:35.7 |
HIP 101604 |
18.44 |
| 2026-02-05 12:00 |
20:35:30.17 |
+27:20:59.3 |
HIP 101604 |
17.95 |
| 2026-02-06 00:00 |
20:35:39.88 |
+27:21:23.6 |
HIP 101604 |
17.70 |
| 2026-02-06 12:00 |
20:35:49.56 |
+27:21:48.6 |
HIP 101604 |
17.71 |
| 2026-02-07 00:00 |
20:35:59.23 |
+27:22:14.3 |
HIP 101604 |
17.98 |
| 2026-02-07 12:00 |
20:36:08.88 |
+27:22:40.7 |
HIP 101604 |
18.49 |
| 2026-02-08 00:00 |
20:36:18.52 |
+27:23:07.7 |
HIP 101604 |
19.23 |
| 2026-02-08 12:00 |
20:36:28.13 |
+27:23:35.4 |
HIP 101604 |
20.16 |
| 2026-02-09 00:00 |
20:36:37.72 |
+27:24:03.8 |
HIP 101604 |
21.27 |
| 2026-02-09 12:00 |
20:36:47.29 |
+27:24:32.8 |
HIP 101604 |
22.52 |
| 2026-02-10 00:00 |
20:36:56.84 |
+27:25:02.5 |
HIP 101837 |
22.54 |
| 2026-02-10 12:00 |
20:37:06.37 |
+27:25:32.8 |
HIP 101837 |
20.61 |
| 2026-02-11 00:00 |
20:37:15.88 |
+27:26:03.8 |
HIP 101837 |
18.72 |
| 2026-02-11 12:00 |
20:37:25.37 |
+27:26:35.5 |
HIP 101837 |
16.90 |
| 2026-02-12 00:00 |
20:37:34.83 |
+27:27:07.8 |
HIP 101837 |
15.17 |
| 2026-02-12 12:00 |
20:37:44.27 |
+27:27:40.7 |
HIP 101837 |
13.55 |
| 2026-02-13 00:00 |
20:37:53.68 |
+27:28:14.3 |
HIP 101837 |
12.10 |
| 2026-02-13 12:00 |
20:38:03.07 |
+27:28:48.5 |
HIP 101837 |
10.87 |
| 2026-02-14 00:00 |
20:38:12.43 |
+27:29:23.4 |
HIP 101837 |
9.96 |
| 2026-02-14 12:00 |
20:38:21.77 |
+27:29:58.9 |
HIP 101837 |
9.45 |
| 2026-02-15 00:00 |
20:38:31.08 |
+27:30:35.0 |
HIP 101837 |
9.40 |
| 2026-02-15 12:00 |
20:38:40.37 |
+27:31:11.8 |
HIP 101837 |
9.82 |
| 2026-02-16 00:00 |
20:38:49.63 |
+27:31:49.1 |
HIP 101837 |
10.65 |
| 2026-02-16 12:00 |
20:38:58.86 |
+27:32:27.1 |
HIP 101837 |
11.81 |
| 2026-02-17 00:00 |
20:39:08.06 |
+27:33:05.7 |
HIP 101837 |
13.20 |
| 2026-02-17 12:00 |
20:39:17.23 |
+27:33:45.0 |
HIP 101837 |
14.77 |
| 2026-02-18 00:00 |
20:39:26.37 |
+27:34:24.8 |
HIP 101837 |
16.45 |
| 2026-02-18 12:00 |
20:39:35.49 |
+27:35:05.2 |
HIP 101837 |
18.22 |
| 2026-02-19 00:00 |
20:39:44.57 |
+27:35:46.2 |
HIP 101982 |
19.39 |
| 2026-02-19 12:00 |
20:39:53.62 |
+27:36:27.8 |
HIP 102086 |
19.44 |
| 2026-02-20 00:00 |
20:40:02.64 |
+27:37:10.0 |
HIP 102086 |
17.36 |
| 2026-02-20 12:00 |
20:40:11.63 |
+27:37:52.8 |
HIP 102086 |
15.31 |
| 2026-02-21 00:00 |
20:40:20.58 |
+27:38:36.2 |
HIP 102086 |
13.27 |
| 2026-02-21 12:00 |
20:40:29.50 |
+27:39:20.1 |
HIP 102086 |
11.27 |
| 2026-02-22 00:00 |
20:40:38.39 |
+27:40:04.7 |
HIP 102086 |
9.33 |
| 2026-02-22 12:00 |
20:40:47.24 |
+27:40:49.7 |
HIP 102086 |
7.49 |
| 2026-02-23 00:00 |
20:40:56.06 |
+27:41:35.4 |
HIP 102086 |
5.83 |
| 2026-02-23 12:00 |
20:41:04.84 |
+27:42:21.6 |
HIP 102086 |
4.57 |
| 2026-02-24 00:00 |
20:41:13.59 |
+27:43:08.4 |
HIP 102086 |
4.07 |