메타데이터
| 항목 |
값 |
| Designation |
C/2021 D2 (ZTF) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-02-03T23:30:34.882560Z |
| Orbit solution date (soln_date, UTC) |
2026-01-13T08:12:19Z |
| Obs used |
654 |
| NEO |
- |
| M1 |
13.300 |
| K1 |
4.500 |
| PC |
- |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2021-11-09.0000000 |
| e |
1.00133730 |
| q (au) |
2.946303 |
| a (au) |
-2203.174195 |
| i (deg) |
83.831242 |
| Ω (om, deg) |
305.677385 |
| ω (w, deg) |
125.029250 |
| M (ma, deg) |
-0.000829 |
밝기
산란 + 전체 선형
$$
M_a = (15.473 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
15.473 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.788 |
| 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 |
| 2021-02-19 |
2021-05-22 |
+15.6409 |
-9.727 |
| 2021-05-22 |
2021-08-10 |
-4.4730 |
+2.199 |
| 2021-08-10 |
2022-02-03 |
+4.5999 |
-2.464 |
| 2022-02-21 |
2023-04-22 |
+12.0730 |
-5.101 |
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 |
07:51:49.43 |
-44:29:41.9 |
HIP 38451 |
11.36 |
| 2026-07-29 12:00 |
07:52:00.73 |
-44:30:40.3 |
HIP 38451 |
10.71 |
| 2026-07-30 00:00 |
07:52:12.02 |
-44:31:39.6 |
HIP 38451 |
10.52 |
| 2026-07-30 12:00 |
07:52:23.30 |
-44:32:39.8 |
HIP 38451 |
10.82 |
| 2026-07-31 00:00 |
07:52:34.55 |
-44:33:40.8 |
HIP 38451 |
11.57 |
| 2026-07-31 12:00 |
07:52:45.78 |
-44:34:42.7 |
HIP 38451 |
12.70 |
| 2026-08-01 00:00 |
07:52:57.00 |
-44:35:45.4 |
HIP 38451 |
14.11 |
| 2026-08-01 12:00 |
07:53:08.19 |
-44:36:49.0 |
HIP 38451 |
15.73 |
| 2026-08-02 00:00 |
07:53:19.37 |
-44:37:53.4 |
HIP 38451 |
17.51 |
| 2026-08-02 12:00 |
07:53:30.52 |
-44:38:58.7 |
HIP 38451 |
19.39 |
| 2026-08-03 00:00 |
07:53:41.65 |
-44:40:04.9 |
HIP 38451 |
21.36 |
| 2026-08-03 12:00 |
07:53:52.76 |
-44:41:11.9 |
HIP 38746 |
22.23 |
| 2026-08-04 00:00 |
07:54:03.84 |
-44:42:19.8 |
HIP 38746 |
20.55 |
| 2026-08-04 12:00 |
07:54:14.91 |
-44:43:28.5 |
HIP 38746 |
18.99 |
| 2026-08-05 00:00 |
07:54:25.94 |
-44:44:38.0 |
HIP 38746 |
17.60 |
| 2026-08-05 12:00 |
07:54:36.96 |
-44:45:48.4 |
HIP 38746 |
16.43 |
| 2026-08-06 00:00 |
07:54:47.94 |
-44:46:59.6 |
HIP 38746 |
15.51 |
| 2026-08-06 12:00 |
07:54:58.90 |
-44:48:11.7 |
HIP 38746 |
14.91 |
| 2026-08-07 00:00 |
07:55:09.84 |
-44:49:24.6 |
HIP 38746 |
14.66 |
| 2026-08-07 12:00 |
07:55:20.75 |
-44:50:38.4 |
HIP 38746 |
14.78 |
| 2026-08-08 00:00 |
07:55:31.63 |
-44:51:53.0 |
HIP 38746 |
15.27 |
| 2026-08-08 12:00 |
07:55:42.48 |
-44:53:08.4 |
HIP 38746 |
16.09 |
| 2026-08-09 00:00 |
07:55:53.30 |
-44:54:24.6 |
HIP 38746 |
17.19 |
| 2026-08-09 12:00 |
07:56:04.09 |
-44:55:41.7 |
HIP 38746 |
18.53 |
| 2026-08-10 00:00 |
07:56:14.85 |
-44:56:59.6 |
HIP 38746 |
20.05 |
| 2026-08-10 12:00 |
07:56:25.58 |
-44:58:18.3 |
HIP 38746 |
21.73 |
| 2026-08-11 00:00 |
07:56:36.27 |
-44:59:37.8 |
HIP 38746 |
23.53 |
| 2026-08-11 12:00 |
07:56:46.94 |
-45:00:58.2 |
HIP 38746 |
25.42 |
| 2026-08-12 00:00 |
07:56:57.57 |
-45:02:19.3 |
HIP 39014 |
24.36 |
| 2026-08-12 12:00 |
07:57:08.17 |
-45:03:41.3 |
HIP 39014 |
22.08 |
| 2026-08-13 00:00 |
07:57:18.73 |
-45:05:04.1 |
HIP 39014 |
19.81 |
| 2026-08-13 12:00 |
07:57:29.26 |
-45:06:27.7 |
HIP 39014 |
17.56 |
| 2026-08-14 00:00 |
07:57:39.75 |
-45:07:52.1 |
HIP 39014 |
15.33 |
| 2026-08-14 12:00 |
07:57:50.20 |
-45:09:17.2 |
HIP 39014 |
13.14 |
| 2026-08-15 00:00 |
07:58:00.62 |
-45:10:43.2 |
HIP 39014 |
11.01 |
| 2026-08-15 12:00 |
07:58:10.99 |
-45:12:10.0 |
HIP 39014 |
8.99 |
| 2026-08-16 00:00 |
07:58:21.33 |
-45:13:37.5 |
HIP 39014 |
7.16 |
| 2026-08-16 12:00 |
07:58:31.63 |
-45:15:05.8 |
HIP 39014 |
5.73 |
| 2026-08-17 00:00 |
07:58:41.89 |
-45:16:34.9 |
HIP 39014 |
5.05 |
| 2026-08-17 12:00 |
07:58:52.11 |
-45:18:04.8 |
HIP 39014 |
5.40 |
| 2026-08-18 00:00 |
07:59:02.29 |
-45:19:35.4 |
HIP 39014 |
6.64 |
| 2026-08-18 12:00 |
07:59:12.42 |
-45:21:06.8 |
HIP 39014 |
8.37 |
| 2026-08-19 00:00 |
07:59:22.51 |
-45:22:39.0 |
HIP 39014 |
10.36 |