C/1989 T1 (Helin-Roman-Alu)
メタデータ
| 項目 |
値 |
| Designation |
C/1989 T1 (Helin-Roman-Alu) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1989-12-15T22:37:06.297600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
120 |
| NEO |
- |
| M1 |
12.500 |
| K1 |
13.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1989-11-17.0000000 |
| e |
0.99061399 |
| q (au) |
1.047319 |
| a (au) |
111.582949 |
| i (deg) |
46.036538 |
| Ω (om, deg) |
8.519172 |
| ω (w, deg) |
68.125993 |
| M (ma, deg) |
359.975798 |
等級
散乱 + 全体線形
$$
M_a = (10.273 + 3.956\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.273 |
| n |
3.956 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 1989-10-01 |
1989-12-07 |
+5.1672 |
-0.345 |
| 1989-12-16 |
1990-11-17 |
-15.8129 |
+1.431 |
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) |
| 2026-02-03 00:00 |
14:31:42.37 |
-53:05:12.7 |
HIP 70850 |
24.49 |
| 2026-02-03 12:00 |
14:31:42.23 |
-53:05:32.4 |
HIP 70850 |
24.63 |
| 2026-02-04 00:00 |
14:31:42.05 |
-53:05:52.1 |
HIP 70850 |
24.77 |
| 2026-02-04 12:00 |
14:31:41.85 |
-53:06:11.7 |
HIP 71037 |
24.57 |
| 2026-02-05 00:00 |
14:31:41.62 |
-53:06:31.2 |
HIP 71037 |
24.24 |
| 2026-02-05 12:00 |
14:31:41.36 |
-53:06:50.6 |
HIP 71037 |
23.92 |
| 2026-02-06 00:00 |
14:31:41.07 |
-53:07:10.0 |
HIP 71037 |
23.60 |
| 2026-02-06 12:00 |
14:31:40.75 |
-53:07:29.3 |
HIP 71037 |
23.28 |
| 2026-02-07 00:00 |
14:31:40.40 |
-53:07:48.4 |
HIP 71037 |
22.96 |
| 2026-02-07 12:00 |
14:31:40.03 |
-53:08:07.5 |
HIP 71037 |
22.64 |
| 2026-02-08 00:00 |
14:31:39.62 |
-53:08:26.6 |
HIP 71037 |
22.32 |
| 2026-02-08 12:00 |
14:31:39.19 |
-53:08:45.5 |
HIP 71037 |
22.01 |
| 2026-02-09 00:00 |
14:31:38.72 |
-53:09:04.3 |
HIP 71037 |
21.70 |
| 2026-02-09 12:00 |
14:31:38.23 |
-53:09:23.0 |
HIP 71037 |
21.39 |
| 2026-02-10 00:00 |
14:31:37.71 |
-53:09:41.7 |
HIP 71037 |
21.08 |
| 2026-02-10 12:00 |
14:31:37.16 |
-53:10:00.3 |
HIP 71037 |
20.77 |
| 2026-02-11 00:00 |
14:31:36.58 |
-53:10:18.7 |
HIP 71037 |
20.47 |
| 2026-02-11 12:00 |
14:31:35.97 |
-53:10:37.1 |
HIP 71037 |
20.16 |
| 2026-02-12 00:00 |
14:31:35.33 |
-53:10:55.3 |
HIP 71037 |
19.86 |
| 2026-02-12 12:00 |
14:31:34.67 |
-53:11:13.5 |
HIP 71037 |
19.57 |
| 2026-02-13 00:00 |
14:31:33.97 |
-53:11:31.6 |
HIP 71037 |
19.27 |
| 2026-02-13 12:00 |
14:31:33.25 |
-53:11:49.5 |
HIP 71037 |
18.98 |
| 2026-02-14 00:00 |
14:31:32.49 |
-53:12:07.4 |
HIP 71037 |
18.69 |
| 2026-02-14 12:00 |
14:31:31.71 |
-53:12:25.1 |
HIP 71037 |
18.41 |
| 2026-02-15 00:00 |
14:31:30.90 |
-53:12:42.8 |
HIP 71037 |
18.12 |
| 2026-02-15 12:00 |
14:31:30.06 |
-53:13:00.3 |
HIP 71037 |
17.84 |
| 2026-02-16 00:00 |
14:31:29.19 |
-53:13:17.7 |
HIP 71037 |
17.57 |
| 2026-02-16 12:00 |
14:31:28.30 |
-53:13:35.0 |
HIP 71037 |
17.30 |
| 2026-02-17 00:00 |
14:31:27.37 |
-53:13:52.2 |
HIP 71037 |
17.03 |
| 2026-02-17 12:00 |
14:31:26.42 |
-53:14:09.3 |
HIP 71037 |
16.76 |
| 2026-02-18 00:00 |
14:31:25.44 |
-53:14:26.3 |
HIP 71037 |
16.51 |
| 2026-02-18 12:00 |
14:31:24.43 |
-53:14:43.1 |
HIP 71037 |
16.25 |
| 2026-02-19 00:00 |
14:31:23.39 |
-53:14:59.8 |
HIP 71037 |
16.00 |
| 2026-02-19 12:00 |
14:31:22.33 |
-53:15:16.5 |
HIP 71037 |
15.76 |
| 2026-02-20 00:00 |
14:31:21.23 |
-53:15:32.9 |
HIP 71037 |
15.52 |
| 2026-02-20 12:00 |
14:31:20.11 |
-53:15:49.3 |
HIP 71037 |
15.28 |
| 2026-02-21 00:00 |
14:31:18.96 |
-53:16:05.5 |
HIP 71037 |
15.06 |
| 2026-02-21 12:00 |
14:31:17.78 |
-53:16:21.7 |
HIP 71037 |
14.84 |
| 2026-02-22 00:00 |
14:31:16.58 |
-53:16:37.7 |
HIP 71037 |
14.62 |
| 2026-02-22 12:00 |
14:31:15.35 |
-53:16:53.5 |
HIP 71037 |
14.42 |
| 2026-02-23 00:00 |
14:31:14.09 |
-53:17:09.3 |
HIP 71037 |
14.22 |
| 2026-02-23 12:00 |
14:31:12.80 |
-53:17:24.9 |
HIP 71037 |
14.03 |
| 2026-02-24 00:00 |
14:31:11.49 |
-53:17:40.3 |
HIP 71037 |
13.84 |