메타데이터
| 항목 |
값 |
| Designation |
C/2019 S4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-04-07T22:29:16.782720Z |
| Orbit solution date (soln_date, UTC) |
2021-09-20T00:12:43Z |
| Obs used |
267 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
13.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-09-17T10:53:32.640000Z |
| Discovery magnitude (MPC) |
20.30 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating 궤도요소
| 항목 |
값 |
| Epoch (epoch_cal, TDB) |
2020-02-18.0000000 |
| e |
0.98581834 |
| q (au) |
3.441733 |
| a (au) |
242.688906 |
| i (deg) |
92.025259 |
| Ω (om, deg) |
63.169569 |
| ω (w, deg) |
71.354510 |
| M (ma, deg) |
359.986982 |
밝기
산란 + 전체 선형
$$
M_a = (6.827 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
모델 상수
| 항목 |
값 |
| H0 |
6.827 |
| 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 |
| 2019-09-17 |
2020-04-01 |
+21.5169 |
-10.890 |
| 2020-05-29 |
2020-10-30 |
-14.1476 |
+7.524 |
| 2020-10-30 |
2021-09-12 |
+6.0879 |
-4.406 |
log10 r = log10(태양거리/AU), Δ = 지구거리(AU)
천체력
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
15:48:18.99 |
-38:08:34.9 |
HIP 77395 |
7.84 |
| 2026-05-12 12:00 |
15:48:08.90 |
-38:08:34.8 |
HIP 77395 |
6.94 |
| 2026-05-13 00:00 |
15:47:58.80 |
-38:08:34.3 |
HIP 77395 |
6.53 |
| 2026-05-13 12:00 |
15:47:48.68 |
-38:08:33.4 |
HIP 77395 |
6.70 |
| 2026-05-14 00:00 |
15:47:38.56 |
-38:08:32.1 |
HIP 77395 |
7.42 |
| 2026-05-14 12:00 |
15:47:28.43 |
-38:08:30.4 |
HIP 77388 |
8.38 |
| 2026-05-15 00:00 |
15:47:18.30 |
-38:08:28.4 |
HIP 77388 |
9.62 |
| 2026-05-15 12:00 |
15:47:08.15 |
-38:08:25.9 |
HIP 77388 |
11.08 |
| 2026-05-16 00:00 |
15:46:58.01 |
-38:08:23.0 |
HIP 77388 |
12.69 |
| 2026-05-16 12:00 |
15:46:47.86 |
-38:08:19.8 |
HIP 77388 |
14.41 |
| 2026-05-17 00:00 |
15:46:37.70 |
-38:08:16.2 |
HIP 77388 |
16.19 |
| 2026-05-17 12:00 |
15:46:27.55 |
-38:08:12.2 |
HIP 77358 |
18.00 |
| 2026-05-18 00:00 |
15:46:17.39 |
-38:08:07.9 |
HIP 77358 |
19.36 |
| 2026-05-18 12:00 |
15:46:07.23 |
-38:08:03.1 |
HIP 77358 |
20.82 |
| 2026-05-19 00:00 |
15:45:57.07 |
-38:07:58.0 |
HIP 77358 |
22.36 |
| 2026-05-19 12:00 |
15:45:46.92 |
-38:07:52.5 |
HIP 77358 |
23.97 |
| 2026-05-20 00:00 |
15:45:36.77 |
-38:07:46.7 |
HIP 77358 |
25.63 |
| 2026-05-20 12:00 |
15:45:26.62 |
-38:07:40.5 |
HIP 77358 |
27.33 |
| 2026-05-21 00:00 |
15:45:16.47 |
-38:07:33.9 |
HIP 76987 |
27.69 |
| 2026-05-21 12:00 |
15:45:06.33 |
-38:07:26.9 |
HIP 76987 |
25.86 |
| 2026-05-22 00:00 |
15:44:56.20 |
-38:07:19.6 |
HIP 76987 |
24.07 |
| 2026-05-22 12:00 |
15:44:46.07 |
-38:07:12.0 |
HIP 76987 |
22.30 |
| 2026-05-23 00:00 |
15:44:35.96 |
-38:07:04.0 |
HIP 76987 |
20.58 |
| 2026-05-23 12:00 |
15:44:25.85 |
-38:06:55.6 |
HIP 76987 |
18.91 |
| 2026-05-24 00:00 |
15:44:15.75 |
-38:06:46.9 |
HIP 76987 |
17.30 |
| 2026-05-24 12:00 |
15:44:05.66 |
-38:06:37.8 |
HIP 76987 |
15.79 |
| 2026-05-25 00:00 |
15:43:55.58 |
-38:06:28.4 |
HIP 76987 |
14.38 |
| 2026-05-25 12:00 |
15:43:45.52 |
-38:06:18.7 |
HIP 76987 |
13.12 |
| 2026-05-26 00:00 |
15:43:35.47 |
-38:06:08.6 |
HIP 76987 |
12.06 |
| 2026-05-26 12:00 |
15:43:25.43 |
-38:05:58.2 |
HIP 76987 |
11.24 |
| 2026-05-27 00:00 |
15:43:15.41 |
-38:05:47.4 |
HIP 76987 |
10.73 |
| 2026-05-27 12:00 |
15:43:05.40 |
-38:05:36.3 |
HIP 76987 |
10.57 |
| 2026-05-28 00:00 |
15:42:55.41 |
-38:05:24.9 |
HIP 76987 |
10.77 |
| 2026-05-28 12:00 |
15:42:45.44 |
-38:05:13.2 |
HIP 76987 |
11.31 |
| 2026-05-29 00:00 |
15:42:35.48 |
-38:05:01.1 |
HIP 76890 |
10.56 |
| 2026-05-29 12:00 |
15:42:25.55 |
-38:04:48.8 |
HIP 76890 |
9.62 |
| 2026-05-30 00:00 |
15:42:15.63 |
-38:04:36.1 |
HIP 76890 |
9.01 |
| 2026-05-30 12:00 |
15:42:05.73 |
-38:04:23.1 |
HIP 76890 |
8.82 |
| 2026-05-31 00:00 |
15:41:55.86 |
-38:04:09.7 |
HIP 76890 |
9.06 |
| 2026-05-31 12:00 |
15:41:46.01 |
-38:03:56.1 |
HIP 76890 |
9.69 |
| 2026-06-01 00:00 |
15:41:36.18 |
-38:03:42.2 |
HIP 76890 |
10.66 |
| 2026-06-01 12:00 |
15:41:26.37 |
-38:03:27.9 |
HIP 76890 |
11.87 |
| 2026-06-02 00:00 |
15:41:16.59 |
-38:03:13.4 |
HIP 76890 |
13.26 |