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) |
| 2026-06-01 00:00 |
10:42:38.00 |
-15:51:36.5 |
HIP 52364 |
15.63 |
| 2026-06-01 12:00 |
10:42:38.70 |
-15:50:59.7 |
HIP 52364 |
16.25 |
| 2026-06-02 00:00 |
10:42:39.46 |
-15:50:23.2 |
HIP 52364 |
16.88 |
| 2026-06-02 12:00 |
10:42:40.27 |
-15:49:47.2 |
HIP 52364 |
17.50 |
| 2026-06-03 00:00 |
10:42:41.15 |
-15:49:11.5 |
HIP 52364 |
18.13 |
| 2026-06-03 12:00 |
10:42:42.09 |
-15:48:36.2 |
HIP 52364 |
18.76 |
| 2026-06-04 00:00 |
10:42:43.08 |
-15:48:01.3 |
HIP 52364 |
19.39 |
| 2026-06-04 12:00 |
10:42:44.13 |
-15:47:26.8 |
HIP 52364 |
20.01 |
| 2026-06-05 00:00 |
10:42:45.24 |
-15:46:52.7 |
HIP 52364 |
20.64 |
| 2026-06-05 12:00 |
10:42:46.41 |
-15:46:19.0 |
HIP 52364 |
21.27 |
| 2026-06-06 00:00 |
10:42:47.64 |
-15:45:45.6 |
HIP 52364 |
21.90 |
| 2026-06-06 12:00 |
10:42:48.92 |
-15:45:12.7 |
HIP 52364 |
22.53 |
| 2026-06-07 00:00 |
10:42:50.27 |
-15:44:40.2 |
HIP 52364 |
23.16 |
| 2026-06-07 12:00 |
10:42:51.67 |
-15:44:08.1 |
HIP 52364 |
23.79 |
| 2026-06-08 00:00 |
10:42:53.13 |
-15:43:36.4 |
HIP 52361 |
24.28 |
| 2026-06-08 12:00 |
10:42:54.64 |
-15:43:05.1 |
HIP 52361 |
24.00 |
| 2026-06-09 00:00 |
10:42:56.22 |
-15:42:34.2 |
HIP 52361 |
23.75 |
| 2026-06-09 12:00 |
10:42:57.85 |
-15:42:03.8 |
HIP 52361 |
23.52 |
| 2026-06-10 00:00 |
10:42:59.53 |
-15:41:33.7 |
HIP 52361 |
23.33 |
| 2026-06-10 12:00 |
10:43:01.28 |
-15:41:04.1 |
HIP 52361 |
23.16 |
| 2026-06-11 00:00 |
10:43:03.08 |
-15:40:34.9 |
HIP 52361 |
23.03 |
| 2026-06-11 12:00 |
10:43:04.94 |
-15:40:06.1 |
HIP 52361 |
22.92 |
| 2026-06-12 00:00 |
10:43:06.85 |
-15:39:37.7 |
HIP 52361 |
22.86 |
| 2026-06-12 12:00 |
10:43:08.82 |
-15:39:09.7 |
HIP 52361 |
22.82 |
| 2026-06-13 00:00 |
10:43:10.84 |
-15:38:42.2 |
HIP 52361 |
22.82 |
| 2026-06-13 12:00 |
10:43:12.93 |
-15:38:15.1 |
HIP 52361 |
22.85 |
| 2026-06-14 00:00 |
10:43:15.06 |
-15:37:48.5 |
HIP 52361 |
22.91 |
| 2026-06-14 12:00 |
10:43:17.25 |
-15:37:22.2 |
HIP 52361 |
23.01 |
| 2026-06-15 00:00 |
10:43:19.50 |
-15:36:56.4 |
HIP 52361 |
23.15 |
| 2026-06-15 12:00 |
10:43:21.80 |
-15:36:31.1 |
HIP 52361 |
23.32 |
| 2026-06-16 00:00 |
10:43:24.16 |
-15:36:06.2 |
HIP 52361 |
23.52 |
| 2026-06-16 12:00 |
10:43:26.57 |
-15:35:41.7 |
HIP 52361 |
23.76 |
| 2026-06-17 00:00 |
10:43:29.03 |
-15:35:17.7 |
HIP 52361 |
24.03 |
| 2026-06-17 12:00 |
10:43:31.55 |
-15:34:54.1 |
HIP 52361 |
24.34 |
| 2026-06-18 00:00 |
10:43:34.12 |
-15:34:30.9 |
HIP 52361 |
24.68 |
| 2026-06-18 12:00 |
10:43:36.74 |
-15:34:08.2 |
HIP 52361 |
25.05 |
| 2026-06-19 00:00 |
10:43:39.42 |
-15:33:45.9 |
HIP 52361 |
25.44 |
| 2026-06-19 12:00 |
10:43:42.15 |
-15:33:24.1 |
HIP 52361 |
25.87 |
| 2026-06-20 00:00 |
10:43:44.93 |
-15:33:02.7 |
HIP 52361 |
26.33 |
| 2026-06-20 12:00 |
10:43:47.76 |
-15:32:41.8 |
HIP 52361 |
26.82 |
| 2026-06-21 00:00 |
10:43:50.65 |
-15:32:21.3 |
HIP 52361 |
27.33 |
| 2026-06-21 12:00 |
10:43:53.58 |
-15:32:01.3 |
HIP 52361 |
27.87 |
| 2026-06-22 00:00 |
10:43:56.57 |
-15:31:41.7 |
HIP 52361 |
28.44 |