メタデータ
| 項目 |
値 |
| Designation |
C/2021 D1 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-02-27T14:36:45.581760Z |
| Orbit solution date (soln_date, UTC) |
2021-07-06T18:29:33Z |
| Obs used |
342 |
| NEO |
- |
| M1 |
13.300 |
| K1 |
14.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-02-28T17:29:51.648000Z |
| Discovery magnitude (MPC) |
14.60 R |
| Discovery observatory (MPC) |
K88 · GINOP-KHK, Piszkéstető |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-03-19.0000000 |
| e |
0.99064883 |
| q (au) |
0.901798 |
| a (au) |
96.436853 |
| i (deg) |
31.460781 |
| Ω (om, deg) |
311.271222 |
| ω (w, deg) |
72.222962 |
| M (ma, deg) |
0.020181 |
等級
散乱 + 全体線形
$$
M_a = (14.258 + 5.845\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
14.258 |
| n |
5.845 |
| gf |
1.000 |
| gb |
-0.610 |
| 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 |
| 2021-02-28 |
2021-05-11 |
-0.4219 |
-0.927 |
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) |
| 2026-09-20 00:00 |
11:01:24.99 |
-16:29:04.7 |
HIP 53886 |
27.70 |
| 2026-09-20 12:00 |
11:01:31.68 |
-16:29:55.7 |
HIP 53886 |
26.84 |
| 2026-09-21 00:00 |
11:01:38.36 |
-16:30:46.9 |
HIP 53886 |
26.07 |
| 2026-09-21 12:00 |
11:01:45.02 |
-16:31:38.4 |
HIP 53886 |
25.41 |
| 2026-09-22 00:00 |
11:01:51.67 |
-16:32:30.0 |
HIP 53886 |
24.86 |
| 2026-09-22 12:00 |
11:01:58.31 |
-16:33:21.9 |
HIP 53886 |
24.42 |
| 2026-09-23 00:00 |
11:02:04.93 |
-16:34:14.1 |
HIP 53886 |
24.11 |
| 2026-09-23 12:00 |
11:02:11.53 |
-16:35:06.4 |
HIP 53886 |
23.92 |
| 2026-09-24 00:00 |
11:02:18.12 |
-16:35:59.0 |
HIP 53886 |
23.87 |
| 2026-09-24 12:00 |
11:02:24.70 |
-16:36:51.7 |
HIP 53886 |
23.94 |
| 2026-09-25 00:00 |
11:02:31.26 |
-16:37:44.7 |
HIP 53886 |
24.15 |
| 2026-09-25 12:00 |
11:02:37.80 |
-16:38:37.9 |
HIP 53886 |
24.48 |
| 2026-09-26 00:00 |
11:02:44.32 |
-16:39:31.3 |
HIP 53886 |
24.93 |
| 2026-09-26 12:00 |
11:02:50.83 |
-16:40:24.9 |
HIP 53886 |
25.50 |
| 2026-09-27 00:00 |
11:02:57.32 |
-16:41:18.7 |
HIP 53886 |
26.17 |
| 2026-09-27 12:00 |
11:03:03.79 |
-16:42:12.7 |
HIP 54164 |
26.78 |
| 2026-09-28 00:00 |
11:03:10.24 |
-16:43:06.8 |
HIP 54164 |
25.01 |
| 2026-09-28 12:00 |
11:03:16.67 |
-16:44:01.2 |
HIP 54164 |
23.24 |
| 2026-09-29 00:00 |
11:03:23.09 |
-16:44:55.8 |
HIP 54164 |
21.48 |
| 2026-09-29 12:00 |
11:03:29.48 |
-16:45:50.5 |
HIP 54164 |
19.73 |
| 2026-09-30 00:00 |
11:03:35.86 |
-16:46:45.4 |
HIP 54164 |
17.99 |
| 2026-09-30 12:00 |
11:03:42.22 |
-16:47:40.6 |
HIP 54164 |
16.26 |
| 2026-10-01 00:00 |
11:03:48.55 |
-16:48:35.8 |
HIP 54164 |
14.54 |
| 2026-10-01 12:00 |
11:03:54.86 |
-16:49:31.3 |
HIP 54164 |
12.85 |
| 2026-10-02 00:00 |
11:04:01.16 |
-16:50:27.0 |
HIP 54164 |
11.18 |
| 2026-10-02 12:00 |
11:04:07.43 |
-16:51:22.8 |
HIP 54164 |
9.56 |
| 2026-10-03 00:00 |
11:04:13.68 |
-16:52:18.8 |
HIP 54164 |
8.00 |
| 2026-10-03 12:00 |
11:04:19.90 |
-16:53:14.9 |
HIP 54164 |
6.56 |
| 2026-10-04 00:00 |
11:04:26.11 |
-16:54:11.2 |
HIP 54164 |
5.31 |
| 2026-10-04 12:00 |
11:04:32.29 |
-16:55:07.7 |
HIP 54164 |
4.43 |
| 2026-10-05 00:00 |
11:04:38.44 |
-16:56:04.3 |
HIP 54164 |
4.15 |
| 2026-10-05 12:00 |
11:04:44.58 |
-16:57:01.1 |
HIP 54164 |
4.58 |
| 2026-10-06 00:00 |
11:04:50.69 |
-16:57:58.1 |
HIP 54164 |
5.55 |
| 2026-10-06 12:00 |
11:04:56.77 |
-16:58:55.2 |
HIP 54164 |
6.84 |
| 2026-10-07 00:00 |
11:05:02.83 |
-16:59:52.4 |
HIP 54164 |
8.29 |
| 2026-10-07 12:00 |
11:05:08.86 |
-17:00:49.8 |
HIP 54164 |
9.83 |
| 2026-10-08 00:00 |
11:05:14.87 |
-17:01:47.3 |
HIP 54164 |
11.43 |
| 2026-10-08 12:00 |
11:05:20.85 |
-17:02:45.0 |
HIP 54164 |
13.06 |
| 2026-10-09 00:00 |
11:05:26.81 |
-17:03:42.8 |
HIP 54164 |
14.70 |
| 2026-10-09 12:00 |
11:05:32.73 |
-17:04:40.7 |
HIP 54164 |
16.36 |
| 2026-10-10 00:00 |
11:05:38.63 |
-17:05:38.7 |
HIP 54164 |
18.03 |
| 2026-10-10 12:00 |
11:05:44.50 |
-17:06:36.9 |
HIP 54164 |
19.70 |
| 2026-10-11 00:00 |
11:05:50.35 |
-17:07:35.2 |
HIP 54164 |
21.37 |