メタデータ
| 項目 |
値 |
| 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 |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| 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 |
等級
散乱 + 全体線形
$$
M_a = (15.473 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
15.473 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.788 |
| k |
0.800 |
| δ90 |
10.000 |
| パラメータ |
記号 |
範囲 |
説明 |
| 太陽・地球距離が1 AUのときの絶対等級 |
H0 |
-5 to 20 |
彗星の固有の明るさ |
| 測光スロープパラメータ |
n |
2 to 6 |
太陽距離に対する明るさ変化率 |
| 前方散乱非対称係数 |
gf |
0.8 to 1 |
前方散乱の強さ |
| 後方散乱非対称係数 |
gb |
-1 to -0.5 |
後方散乱の強さ |
| 分配係数 |
k |
0.8 to 1 |
前方/後方散乱の寄与比 |
| ダスト/ガス明るさ比 |
δ90 |
1 to 10 |
ダスト散乱とガス放射の相対寄与 |
参考: EPSC-DPS2025-160
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2021-02-19 |
2021-05-22 |
+15.6411 |
-9.727 |
| 2021-05-22 |
2021-08-10 |
-4.4729 |
+2.199 |
| 2021-08-10 |
2022-02-03 |
+4.5999 |
-2.464 |
| 2022-02-21 |
2023-04-22 |
+12.0731 |
-5.101 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
07:23:24.09 |
-47:39:07.8 |
HIP 35853 |
18.20 |
| 2026-03-26 12:00 |
07:23:19.96 |
-47:37:19.0 |
HIP 35853 |
20.06 |
| 2026-03-27 00:00 |
07:23:15.96 |
-47:35:30.0 |
HIP 35853 |
21.94 |
| 2026-03-27 12:00 |
07:23:12.09 |
-47:33:40.9 |
HIP 35853 |
23.82 |
| 2026-03-28 00:00 |
07:23:08.34 |
-47:31:51.7 |
HIP 35853 |
25.71 |
| 2026-03-28 12:00 |
07:23:04.73 |
-47:30:02.4 |
HIP 35853 |
27.60 |
| 2026-03-29 00:00 |
07:23:01.25 |
-47:28:13.1 |
HIP 35709 |
28.20 |
| 2026-03-29 12:00 |
07:22:57.89 |
-47:26:23.7 |
HIP 35709 |
26.29 |
| 2026-03-30 00:00 |
07:22:54.66 |
-47:24:34.2 |
HIP 35709 |
24.40 |
| 2026-03-30 12:00 |
07:22:51.57 |
-47:22:44.7 |
HIP 35709 |
22.51 |
| 2026-03-31 00:00 |
07:22:48.60 |
-47:20:55.1 |
HIP 35709 |
20.62 |
| 2026-03-31 12:00 |
07:22:45.75 |
-47:19:05.5 |
HIP 35709 |
18.75 |
| 2026-04-01 00:00 |
07:22:43.04 |
-47:17:15.9 |
HIP 35709 |
16.89 |
| 2026-04-01 12:00 |
07:22:40.45 |
-47:15:26.4 |
HIP 35709 |
15.05 |
| 2026-04-02 00:00 |
07:22:37.99 |
-47:13:36.8 |
HIP 35709 |
13.23 |
| 2026-04-02 12:00 |
07:22:35.66 |
-47:11:47.2 |
HIP 35709 |
11.43 |
| 2026-04-03 00:00 |
07:22:33.45 |
-47:09:57.7 |
HIP 35709 |
9.67 |
| 2026-04-03 12:00 |
07:22:31.37 |
-47:08:08.2 |
HIP 35709 |
7.98 |
| 2026-04-04 00:00 |
07:22:29.41 |
-47:06:18.7 |
HIP 35709 |
6.39 |
| 2026-04-04 12:00 |
07:22:27.58 |
-47:04:29.4 |
HIP 35709 |
5.00 |
| 2026-04-05 00:00 |
07:22:25.88 |
-47:02:40.1 |
HIP 35709 |
4.03 |
| 2026-04-05 12:00 |
07:22:24.30 |
-47:00:50.8 |
HIP 35709 |
3.81 |
| 2026-04-06 00:00 |
07:22:22.84 |
-46:59:01.7 |
HIP 35709 |
4.43 |
| 2026-04-06 12:00 |
07:22:21.51 |
-46:57:12.6 |
HIP 35709 |
5.62 |
| 2026-04-07 00:00 |
07:22:20.30 |
-46:55:23.7 |
HIP 35709 |
7.09 |
| 2026-04-07 12:00 |
07:22:19.21 |
-46:53:34.9 |
HIP 35709 |
8.71 |
| 2026-04-08 00:00 |
07:22:18.25 |
-46:51:46.2 |
HIP 35709 |
10.40 |
| 2026-04-08 12:00 |
07:22:17.41 |
-46:49:57.7 |
HIP 35709 |
12.12 |
| 2026-04-09 00:00 |
07:22:16.70 |
-46:48:09.3 |
HIP 35709 |
13.88 |
| 2026-04-09 12:00 |
07:22:16.10 |
-46:46:21.1 |
HIP 35709 |
15.64 |
| 2026-04-10 00:00 |
07:22:15.63 |
-46:44:33.0 |
HIP 35584 |
17.27 |
| 2026-04-10 12:00 |
07:22:15.28 |
-46:42:45.2 |
HIP 35584 |
17.10 |
| 2026-04-11 00:00 |
07:22:15.05 |
-46:40:57.5 |
HIP 35584 |
17.13 |
| 2026-04-11 12:00 |
07:22:14.94 |
-46:39:10.0 |
HIP 35584 |
17.37 |
| 2026-04-12 00:00 |
07:22:14.95 |
-46:37:22.8 |
HIP 35584 |
17.80 |
| 2026-04-12 12:00 |
07:22:15.08 |
-46:35:35.7 |
HIP 35584 |
18.42 |
| 2026-04-13 00:00 |
07:22:15.33 |
-46:33:48.9 |
HIP 35584 |
19.20 |
| 2026-04-13 12:00 |
07:22:15.69 |
-46:32:02.4 |
HIP 35584 |
20.13 |
| 2026-04-14 00:00 |
07:22:16.18 |
-46:30:16.0 |
HIP 35584 |
21.17 |
| 2026-04-14 12:00 |
07:22:16.79 |
-46:28:30.0 |
HIP 35584 |
22.33 |
| 2026-04-15 00:00 |
07:22:17.51 |
-46:26:44.2 |
HIP 35584 |
23.57 |
| 2026-04-15 12:00 |
07:22:18.35 |
-46:24:58.7 |
HIP 35584 |
24.89 |
| 2026-04-16 00:00 |
07:22:19.31 |
-46:23:13.5 |
HIP 35584 |
26.26 |