메타데이터
| 항목 |
값 |
| Designation |
C/2018 X2 (Fitzsimmons) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-07-08T12:50:12.180480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:48Z |
| Obs used |
390 |
| NEO |
- |
| M1 |
10.600 |
| K1 |
12.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-12-08T11:10:09.696000Z |
| Discovery magnitude (MPC) |
19.10 c |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2019-02-10.0000000 |
| e |
0.98628022 |
| q (au) |
2.125879 |
| a (au) |
154.949983 |
| i (deg) |
23.068234 |
| Ω (om, deg) |
340.833210 |
| ω (w, deg) |
162.047045 |
| M (ma, deg) |
359.924099 |
밝기
산란 + 전체 선형
$$
M_a = (10.225 + 5.892\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
10.225 |
| n |
5.892 |
| gf |
0.996 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
2.692 |
| 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
천체력
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
19:19:21.54 |
-42:26:54.7 |
HIP 95089 |
15.34 |
| 2026-07-29 12:00 |
19:19:14.06 |
-42:26:51.5 |
HIP 95089 |
16.72 |
| 2026-07-30 00:00 |
19:19:06.61 |
-42:26:47.9 |
HIP 95089 |
18.09 |
| 2026-07-30 12:00 |
19:18:59.18 |
-42:26:43.9 |
HIP 95089 |
19.46 |
| 2026-07-31 00:00 |
19:18:51.79 |
-42:26:39.7 |
HIP 94864 |
19.19 |
| 2026-07-31 12:00 |
19:18:44.42 |
-42:26:35.1 |
HIP 94864 |
18.65 |
| 2026-08-01 00:00 |
19:18:37.09 |
-42:26:30.2 |
HIP 94864 |
18.21 |
| 2026-08-01 12:00 |
19:18:29.78 |
-42:26:24.9 |
HIP 94864 |
17.85 |
| 2026-08-02 00:00 |
19:18:22.51 |
-42:26:19.3 |
HIP 94864 |
17.58 |
| 2026-08-02 12:00 |
19:18:15.27 |
-42:26:13.4 |
HIP 94864 |
17.40 |
| 2026-08-03 00:00 |
19:18:08.07 |
-42:26:07.1 |
HIP 94864 |
17.33 |
| 2026-08-03 12:00 |
19:18:00.89 |
-42:26:00.5 |
HIP 94864 |
17.35 |
| 2026-08-04 00:00 |
19:17:53.75 |
-42:25:53.6 |
HIP 94864 |
17.46 |
| 2026-08-04 12:00 |
19:17:46.65 |
-42:25:46.4 |
HIP 94864 |
17.67 |
| 2026-08-05 00:00 |
19:17:39.58 |
-42:25:38.8 |
HIP 94864 |
17.96 |
| 2026-08-05 12:00 |
19:17:32.54 |
-42:25:30.9 |
HIP 94864 |
18.34 |
| 2026-08-06 00:00 |
19:17:25.54 |
-42:25:22.6 |
HIP 94864 |
18.79 |
| 2026-08-06 12:00 |
19:17:18.59 |
-42:25:14.1 |
HIP 94864 |
19.31 |
| 2026-08-07 00:00 |
19:17:11.66 |
-42:25:05.2 |
HIP 94864 |
19.90 |
| 2026-08-07 12:00 |
19:17:04.78 |
-42:24:56.0 |
HIP 94864 |
20.53 |
| 2026-08-08 00:00 |
19:16:57.94 |
-42:24:46.4 |
HIP 94864 |
21.22 |
| 2026-08-08 12:00 |
19:16:51.13 |
-42:24:36.6 |
HIP 94864 |
21.95 |
| 2026-08-09 00:00 |
19:16:44.37 |
-42:24:26.4 |
HIP 94864 |
22.73 |
| 2026-08-09 12:00 |
19:16:37.64 |
-42:24:15.9 |
HIP 94864 |
23.53 |
| 2026-08-10 00:00 |
19:16:30.96 |
-42:24:05.1 |
HIP 94864 |
24.36 |
| 2026-08-10 12:00 |
19:16:24.33 |
-42:23:54.0 |
HIP 94864 |
25.22 |
| 2026-08-11 00:00 |
19:16:17.73 |
-42:23:42.5 |
HIP 94864 |
26.10 |
| 2026-08-11 12:00 |
19:16:11.18 |
-42:23:30.7 |
HIP 94492 |
26.86 |
| 2026-08-12 00:00 |
19:16:04.67 |
-42:23:18.6 |
HIP 94492 |
25.85 |
| 2026-08-12 12:00 |
19:15:58.21 |
-42:23:06.2 |
HIP 94492 |
24.87 |
| 2026-08-13 00:00 |
19:15:51.79 |
-42:22:53.5 |
HIP 94492 |
23.91 |
| 2026-08-13 12:00 |
19:15:45.43 |
-42:22:40.5 |
HIP 94492 |
22.99 |
| 2026-08-14 00:00 |
19:15:39.10 |
-42:22:27.2 |
HIP 94492 |
22.11 |
| 2026-08-14 12:00 |
19:15:32.83 |
-42:22:13.5 |
HIP 94492 |
21.26 |
| 2026-08-15 00:00 |
19:15:26.60 |
-42:21:59.6 |
HIP 94492 |
20.46 |
| 2026-08-15 12:00 |
19:15:20.42 |
-42:21:45.4 |
HIP 94492 |
19.71 |
| 2026-08-16 00:00 |
19:15:14.29 |
-42:21:30.8 |
HIP 94492 |
19.00 |
| 2026-08-16 12:00 |
19:15:08.21 |
-42:21:16.0 |
HIP 94492 |
18.36 |
| 2026-08-17 00:00 |
19:15:02.18 |
-42:21:00.8 |
HIP 94492 |
17.77 |
| 2026-08-17 12:00 |
19:14:56.20 |
-42:20:45.4 |
HIP 94492 |
17.25 |
| 2026-08-18 00:00 |
19:14:50.28 |
-42:20:29.6 |
HIP 94492 |
16.80 |
| 2026-08-18 12:00 |
19:14:44.40 |
-42:20:13.6 |
HIP 94492 |
16.42 |
| 2026-08-19 00:00 |
19:14:38.58 |
-42:19:57.3 |
HIP 94492 |
16.12 |