メタデータ
| 項目 |
値 |
| Designation |
C/2020 T2 (Palomar) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-07-11T03:28:26.996160Z |
| Orbit solution date (soln_date, UTC) |
2024-07-30T14:57:24Z |
| Obs used |
2755 |
| NEO |
- |
| M1 |
9.500 |
| K1 |
10.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-10-07T12:21:14.400000Z |
| Discovery magnitude (MPC) |
19.33 r |
| Discovery observatory (MPC) |
I41 · Palomar Mountain–ZTF |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-05-15.0000000 |
| e |
0.99342864 |
| q (au) |
2.054696 |
| a (au) |
312.674502 |
| i (deg) |
27.872916 |
| Ω (om, deg) |
83.048376 |
| ω (w, deg) |
150.381486 |
| M (ma, deg) |
359.989813 |
等級
散乱 + 全体線形
$$
M_a = (7.304 + 5.380\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
7.304 |
| n |
5.380 |
| gf |
1.000 |
| gb |
-0.950 |
| k |
0.999 |
| 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 |
| 2019-12-11 |
2021-07-11 |
+4.3368 |
-2.066 |
| 2021-07-11 |
2022-09-21 |
+1.1155 |
-2.046 |
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) |
| 2026-07-29 00:00 |
01:42:34.27 |
-18:41:30.0 |
HIP 8088 |
19.81 |
| 2026-07-29 12:00 |
01:42:33.88 |
-18:42:25.7 |
HIP 8088 |
20.27 |
| 2026-07-30 00:00 |
01:42:33.42 |
-18:43:21.8 |
HIP 8088 |
20.77 |
| 2026-07-30 12:00 |
01:42:32.90 |
-18:44:18.1 |
HIP 8088 |
21.32 |
| 2026-07-31 00:00 |
01:42:32.30 |
-18:45:14.6 |
HIP 8088 |
21.92 |
| 2026-07-31 12:00 |
01:42:31.64 |
-18:46:11.4 |
HIP 8088 |
22.55 |
| 2026-08-01 00:00 |
01:42:30.91 |
-18:47:08.5 |
HIP 8088 |
23.22 |
| 2026-08-01 12:00 |
01:42:30.12 |
-18:48:05.9 |
HIP 8088 |
23.93 |
| 2026-08-02 00:00 |
01:42:29.26 |
-18:49:03.4 |
HIP 7937 |
23.39 |
| 2026-08-02 12:00 |
01:42:28.33 |
-18:50:01.3 |
HIP 7937 |
22.40 |
| 2026-08-03 00:00 |
01:42:27.33 |
-18:50:59.3 |
HIP 7937 |
21.41 |
| 2026-08-03 12:00 |
01:42:26.27 |
-18:51:57.7 |
HIP 7937 |
20.41 |
| 2026-08-04 00:00 |
01:42:25.14 |
-18:52:56.2 |
HIP 7937 |
19.39 |
| 2026-08-04 12:00 |
01:42:23.94 |
-18:53:55.0 |
HIP 7937 |
18.37 |
| 2026-08-05 00:00 |
01:42:22.68 |
-18:54:54.0 |
HIP 7937 |
17.35 |
| 2026-08-05 12:00 |
01:42:21.34 |
-18:55:53.2 |
HIP 7937 |
16.31 |
| 2026-08-06 00:00 |
01:42:19.95 |
-18:56:52.6 |
HIP 7937 |
15.27 |
| 2026-08-06 12:00 |
01:42:18.48 |
-18:57:52.2 |
HIP 7937 |
14.22 |
| 2026-08-07 00:00 |
01:42:16.95 |
-18:58:52.0 |
HIP 7937 |
13.16 |
| 2026-08-07 12:00 |
01:42:15.35 |
-18:59:52.1 |
HIP 7937 |
12.09 |
| 2026-08-08 00:00 |
01:42:13.68 |
-19:00:52.3 |
HIP 7937 |
11.02 |
| 2026-08-08 12:00 |
01:42:11.95 |
-19:01:52.7 |
HIP 7937 |
9.95 |
| 2026-08-09 00:00 |
01:42:10.15 |
-19:02:53.3 |
HIP 7937 |
8.87 |
| 2026-08-09 12:00 |
01:42:08.28 |
-19:03:54.1 |
HIP 7937 |
7.79 |
| 2026-08-10 00:00 |
01:42:06.35 |
-19:04:55.0 |
HIP 7937 |
6.71 |
| 2026-08-10 12:00 |
01:42:04.35 |
-19:05:56.1 |
HIP 7937 |
5.64 |
| 2026-08-11 00:00 |
01:42:02.28 |
-19:06:57.4 |
HIP 7937 |
4.59 |
| 2026-08-11 12:00 |
01:42:00.15 |
-19:07:58.8 |
HIP 7937 |
3.59 |
| 2026-08-12 00:00 |
01:41:57.96 |
-19:09:00.4 |
HIP 7937 |
2.72 |
| 2026-08-12 12:00 |
01:41:55.69 |
-19:10:02.1 |
HIP 7937 |
2.13 |
| 2026-08-13 00:00 |
01:41:53.36 |
-19:11:03.9 |
HIP 7937 |
2.11 |
| 2026-08-13 12:00 |
01:41:50.97 |
-19:12:05.9 |
HIP 7937 |
2.67 |
| 2026-08-14 00:00 |
01:41:48.51 |
-19:13:08.0 |
HIP 7937 |
3.57 |
| 2026-08-14 12:00 |
01:41:45.98 |
-19:14:10.2 |
HIP 7937 |
4.61 |
| 2026-08-15 00:00 |
01:41:43.39 |
-19:15:12.6 |
HIP 7937 |
5.73 |
| 2026-08-15 12:00 |
01:41:40.73 |
-19:16:15.0 |
HIP 7937 |
6.89 |
| 2026-08-16 00:00 |
01:41:38.01 |
-19:17:17.5 |
HIP 7937 |
8.07 |
| 2026-08-16 12:00 |
01:41:35.23 |
-19:18:20.2 |
HIP 7937 |
9.28 |
| 2026-08-17 00:00 |
01:41:32.38 |
-19:19:22.9 |
HIP 7937 |
10.51 |
| 2026-08-17 12:00 |
01:41:29.47 |
-19:20:25.7 |
HIP 7937 |
11.75 |
| 2026-08-18 00:00 |
01:41:26.49 |
-19:21:28.5 |
HIP 7937 |
13.00 |
| 2026-08-18 12:00 |
01:41:23.45 |
-19:22:31.5 |
HIP 7937 |
14.26 |
| 2026-08-19 00:00 |
01:41:20.35 |
-19:23:34.5 |
HIP 7937 |
15.54 |