メタデータ
| 項目 |
値 |
| Designation |
491P/Spacewatch-PANSTARRS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2024-09-06T08:23:41.847360Z |
| Orbit solution date (soln_date, UTC) |
2025-11-21T13:43:12Z |
| Obs used |
455 |
| NEO |
- |
| M1 |
10.900 |
| K1 |
8.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2024-05-30T08:01:15.830400Z |
| Discovery magnitude (MPC) |
21.20 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-12-03.0000000 |
| e |
0.25975071 |
| q (au) |
3.709914 |
| a (au) |
5.011709 |
| i (deg) |
9.371310 |
| Ω (om, deg) |
311.733543 |
| ω (w, deg) |
299.086407 |
| M (ma, deg) |
239.355776 |
等級
散乱 + 全体線形
$$
M_a = (12.212 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.212 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.965 |
| k |
1.000 |
| 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
ファインディングチャート
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
22:20:47.59 |
-07:59:17.9 |
HIP 110273 |
13.37 |
| 2026-03-26 12:00 |
22:21:15.12 |
-07:56:05.2 |
HIP 110273 |
17.07 |
| 2026-03-27 00:00 |
22:21:42.56 |
-07:52:52.6 |
HIP 110396 |
16.38 |
| 2026-03-27 12:00 |
22:22:09.94 |
-07:49:40.2 |
HIP 110396 |
14.90 |
| 2026-03-28 00:00 |
22:22:37.24 |
-07:46:27.9 |
HIP 110396 |
16.97 |
| 2026-03-28 12:00 |
22:23:04.46 |
-07:43:15.7 |
HIP 110396 |
21.57 |
| 2026-03-29 00:00 |
22:23:31.61 |
-07:40:03.7 |
HIP 110396 |
27.44 |
| 2026-03-29 12:00 |
22:23:58.68 |
-07:36:51.9 |
HIP 110532 |
26.04 |
| 2026-03-30 00:00 |
22:24:25.67 |
-07:33:40.2 |
HIP 110532 |
25.70 |
| 2026-03-30 12:00 |
22:24:52.59 |
-07:30:28.7 |
HIP 110780 |
26.48 |
| 2026-03-31 00:00 |
22:25:19.43 |
-07:27:17.4 |
HIP 110780 |
19.22 |
| 2026-03-31 12:00 |
22:25:46.19 |
-07:24:06.2 |
HIP 110780 |
12.10 |
| 2026-04-01 00:00 |
22:26:12.87 |
-07:20:55.3 |
HIP 110780 |
5.67 |
| 2026-04-01 12:00 |
22:26:39.47 |
-07:17:44.5 |
HIP 110780 |
5.05 |
| 2026-04-02 00:00 |
22:27:06.00 |
-07:14:33.8 |
HIP 110780 |
11.21 |
| 2026-04-02 12:00 |
22:27:32.44 |
-07:11:23.4 |
HIP 110780 |
18.22 |
| 2026-04-03 00:00 |
22:27:58.80 |
-07:08:13.2 |
HIP 111014 |
22.04 |
| 2026-04-03 12:00 |
22:28:25.08 |
-07:05:03.1 |
HIP 111014 |
15.05 |
| 2026-04-04 00:00 |
22:28:51.28 |
-07:01:53.3 |
HIP 111014 |
8.53 |
| 2026-04-04 12:00 |
22:29:17.40 |
-06:58:43.7 |
HIP 111014 |
4.85 |
| 2026-04-05 00:00 |
22:29:43.43 |
-06:55:34.3 |
HIP 111014 |
8.83 |
| 2026-04-05 12:00 |
22:30:09.38 |
-06:52:25.1 |
HIP 111014 |
15.34 |
| 2026-04-06 00:00 |
22:30:35.25 |
-06:49:16.1 |
HIP 111170 |
19.21 |
| 2026-04-06 12:00 |
22:31:01.03 |
-06:46:07.3 |
HIP 111170 |
13.52 |
| 2026-04-07 00:00 |
22:31:26.73 |
-06:42:58.8 |
HIP 111170 |
9.91 |
| 2026-04-07 12:00 |
22:31:52.34 |
-06:39:50.5 |
HIP 111170 |
10.71 |
| 2026-04-08 00:00 |
22:32:17.87 |
-06:36:42.5 |
HIP 111274 |
9.54 |
| 2026-04-08 12:00 |
22:32:43.30 |
-06:33:34.7 |
HIP 111274 |
6.02 |
| 2026-04-09 00:00 |
22:33:08.66 |
-06:30:27.1 |
HIP 111274 |
8.97 |
| 2026-04-09 12:00 |
22:33:33.92 |
-06:27:19.8 |
HIP 111274 |
14.93 |
| 2026-04-10 00:00 |
22:33:59.09 |
-06:24:12.8 |
HIP 111274 |
21.51 |
| 2026-04-10 12:00 |
22:34:24.18 |
-06:21:06.0 |
HIP 111274 |
28.26 |
| 2026-04-11 00:00 |
22:34:49.17 |
-06:17:59.5 |
HIP 111531 |
30.56 |
| 2026-04-11 12:00 |
22:35:14.08 |
-06:14:53.2 |
HIP 111531 |
31.25 |
| 2026-04-12 00:00 |
22:35:38.89 |
-06:11:47.3 |
HIP 111668 |
25.80 |
| 2026-04-12 12:00 |
22:36:03.61 |
-06:08:41.6 |
HIP 111668 |
19.05 |
| 2026-04-13 00:00 |
22:36:28.24 |
-06:05:36.2 |
HIP 111668 |
12.45 |
| 2026-04-13 12:00 |
22:36:52.77 |
-06:02:31.2 |
HIP 111668 |
6.43 |
| 2026-04-14 00:00 |
22:37:17.21 |
-05:59:26.4 |
HIP 111668 |
4.61 |
| 2026-04-14 12:00 |
22:37:41.56 |
-05:56:21.9 |
HIP 111668 |
9.67 |
| 2026-04-15 00:00 |
22:38:05.81 |
-05:53:17.8 |
HIP 111792 |
7.46 |
| 2026-04-15 12:00 |
22:38:29.96 |
-05:50:13.9 |
HIP 111792 |
3.01 |
| 2026-04-16 00:00 |
22:38:54.02 |
-05:47:10.4 |
HIP 111792 |
7.28 |