78P/Gehrels 2
메타데이터
| 항목 | 값 |
|---|---|
| Designation | 78P/Gehrels 2 |
| Type | P |
| Perihelion (tp_cal, UTC) | 2019-04-03T05:25:38.591040Z |
| Orbit solution date (soln_date, UTC) | 2026-01-07T20:29:55Z |
| Obs used | 6051 |
| NEO | - |
| M1 | 9.100 |
| K1 | 13.250 |
| PC | 0.030 |
Osculating 궤도요소
| 항목 | 값 |
|---|---|
| Epoch (epoch_cal, TDB) | 2016-01-12.0000000 |
| e | 0.46119248 |
| q (au) | 2.013767 |
| a (au) | 3.737452 |
| i (deg) | 6.250385 |
| Ω (om, deg) | 210.559217 |
| ω (w, deg) | 192.734588 |
| M (ma, deg) | 199.416671 |
밝기
산란 + 전체 선형
$$ M_a = (7.458 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
모델 상수
| 항목 | 값 |
|---|---|
| H0 | 7.458 |
| n | 6.000 |
| gf | 1.000 |
| gb | -1.000 |
| k | 1.000 |
| δ90 | 10.000 |
| 파라미터 | 기호 | 범위 | 설명 |
|---|---|---|---|
| 태양·지구거리 1 AU에서의 절대등급 | H0 | -5 to 20 | 혜성의 고유 밝기 |
| 광도 기울기 파라미터 | n | 2 to 6 | 태양거리 변화에 따른 밝기 변화율 |
| 전방 산란 비대칭 계수 | gf |
0.8 to 1 | 전방 산란의 강도 |
| 후방 산란 비대칭 계수 | gb |
-1 to -0.5 | 후방 산란의 강도 |
| 분할 계수 | k | 0.8 to 1 | 전·후방 산란 기여도 비율 |
| 먼지/가스 밝기 비 | δ90 | 1 to 10 | 코마에서 먼지 산란 대비 가스 방출의 상대 기여 |
참고: EPSC-DPS2025-160
잔차 (구간 선형)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 시작일 (UTC) | 끝 (UTC) | a | b |
|---|---|---|---|
| 2025-04-25 | 2025-10-23 | -2.7160 | +0.762 |
| 2025-10-23 | 2026-01-12 | +4.3920 | -2.104 |
log10 r = log10(태양거리/AU), Δ = 지구거리(AU)
찾아보기
천체력
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 22:37:18.60 | -05:27:13.7 | HIP 111581 | 23.45 |
| 2026-02-03 12:00 | 22:38:15.72 | -05:22:20.0 | HIP 111792 | 30.94 |
| 2026-02-04 00:00 | 22:39:12.92 | -05:17:25.2 | HIP 111921 | 36.25 |
| 2026-02-04 12:00 | 22:40:10.19 | -05:12:29.3 | HIP 111921 | 27.78 |
| 2026-02-05 00:00 | 22:41:07.53 | -05:07:32.3 | HIP 112078 | 14.63 |
| 2026-02-05 12:00 | 22:42:04.94 | -05:02:34.1 | HIP 112078 | 3.55 |
| 2026-02-06 00:00 | 22:43:02.42 | -04:57:34.9 | HIP 112135 | 3.48 |
| 2026-02-06 12:00 | 22:43:59.98 | -04:52:34.7 | HIP 112309 | 13.77 |
| 2026-02-07 00:00 | 22:44:57.60 | -04:47:33.3 | HIP 112309 | 7.43 |
| 2026-02-07 12:00 | 22:45:55.30 | -04:42:30.9 | HIP 112309 | 19.60 |
| 2026-02-08 00:00 | 22:46:53.06 | -04:37:27.4 | HIP 112617 | 24.50 |
| 2026-02-08 12:00 | 22:47:50.90 | -04:32:22.9 | HIP 112617 | 10.15 |
| 2026-02-09 00:00 | 22:48:48.81 | -04:27:17.3 | HIP 112617 | 8.53 |
| 2026-02-09 12:00 | 22:49:46.78 | -04:22:10.7 | HIP 112617 | 22.63 |
| 2026-02-10 00:00 | 22:50:44.83 | -04:17:03.1 | HIP 112617 | 37.73 |
| 2026-02-10 12:00 | 22:51:42.94 | -04:11:54.4 | HIP 113091 | 39.42 |
| 2026-02-11 00:00 | 22:52:41.12 | -04:06:44.7 | HIP 113091 | 29.48 |
| 2026-02-11 12:00 | 22:53:39.38 | -04:01:34.0 | HIP 113091 | 25.66 |
| 2026-02-12 00:00 | 22:54:37.70 | -03:56:22.3 | HIP 113091 | 30.41 |
| 2026-02-12 12:00 | 22:55:36.09 | -03:51:09.7 | HIP 113303 | 25.75 |
| 2026-02-13 00:00 | 22:56:34.55 | -03:45:56.0 | HIP 113303 | 14.48 |
| 2026-02-13 12:00 | 22:57:33.07 | -03:40:41.4 | HIP 113391 | 5.08 |
| 2026-02-14 00:00 | 22:58:31.66 | -03:35:25.8 | HIP 113391 | 10.47 |
| 2026-02-14 12:00 | 22:59:30.32 | -03:30:09.2 | HIP 113391 | 26.03 |
| 2026-02-15 00:00 | 23:00:29.05 | -03:24:51.7 | HIP 113718 | 33.15 |
| 2026-02-15 12:00 | 23:01:27.85 | -03:19:33.3 | HIP 113718 | 31.88 |
| 2026-02-16 00:00 | 23:02:26.71 | -03:14:13.9 | HIP 113727 | 33.98 |
| 2026-02-16 12:00 | 23:03:25.63 | -03:08:53.6 | HIP 113956 | 27.67 |
| 2026-02-17 00:00 | 23:04:24.63 | -03:03:32.4 | HIP 113956 | 26.37 |
| 2026-02-17 12:00 | 23:05:23.69 | -02:58:10.3 | HIP 113956 | 33.43 |
| 2026-02-18 00:00 | 23:06:22.81 | -02:52:47.3 | HIP 114313 | 44.82 |
| 2026-02-18 12:00 | 23:07:22.00 | -02:47:23.5 | HIP 114313 | 29.22 |
| 2026-02-19 00:00 | 23:08:21.25 | -02:41:58.7 | HIP 114313 | 13.91 |
| 2026-02-19 12:00 | 23:09:20.57 | -02:36:33.2 | HIP 114313 | 5.45 |
| 2026-02-20 00:00 | 23:10:19.95 | -02:31:06.7 | HIP 114313 | 19.09 |
| 2026-02-20 12:00 | 23:11:19.40 | -02:25:39.4 | HIP 114551 | 26.47 |
| 2026-02-21 00:00 | 23:12:18.91 | -02:20:11.3 | HIP 114551 | 17.44 |
| 2026-02-21 12:00 | 23:13:18.48 | -02:14:42.4 | HIP 114618 | 11.07 |
| 2026-02-22 00:00 | 23:14:18.12 | -02:09:12.7 | HIP 114618 | 17.28 |
| 2026-02-22 12:00 | 23:15:17.81 | -02:03:42.2 | HIP 114618 | 31.31 |
| 2026-02-23 00:00 | 23:16:17.57 | -01:58:10.9 | HIP 114914 | 23.40 |
| 2026-02-23 12:00 | 23:17:17.39 | -01:52:38.8 | HIP 115074 | 17.60 |
| 2026-02-24 00:00 | 23:18:17.28 | -01:47:06.0 | HIP 115074 | 7.28 |