메타데이터

항목	값
Designation	177P/Barnard
Type	P
Perihelion (tp_cal, UTC)	2006-08-28T16:23:52.091520Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:27:46Z
Obs used	1702
NEO	Yes
M1	15.700
K1	13.000
PC	0.030

Osculating 궤도요소

항목	값
Epoch (epoch_cal, TDB)	2006-04-24.0000000
e	0.95444204
q (au)	1.107271
a (au)	24.304669
i (deg)	31.216459
Ω (om, deg)	272.067721
ω (w, deg)	60.453551
M (ma, deg)	358.957950

밝기

산란 + 전체 선형

$$ M_a = (15.195 + 4.041\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

모델 상수

항목	값
H0	15.195
n	4.041
gf	1.000
gb	-0.500
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
2006-06-23	2006-08-28	+13.5160	-2.197
2006-08-28	2006-11-01	-5.2733	-2.545
2006-11-01	2006-12-11	+35.3909	-8.724

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	08:40:22.56	-05:10:11.1	HIP 42461	23.57
2026-05-12 12:00	08:40:23.48	-05:09:54.5	HIP 42461	23.50
2026-05-13 00:00	08:40:24.42	-05:09:38.1	HIP 42461	23.44
2026-05-13 12:00	08:40:25.39	-05:09:21.8	HIP 42461	23.38
2026-05-14 00:00	08:40:26.39	-05:09:05.7	HIP 42461	23.35
2026-05-14 12:00	08:40:27.42	-05:08:49.8	HIP 42461	23.32
2026-05-15 00:00	08:40:28.47	-05:08:34.0	HIP 42461	23.31
2026-05-15 12:00	08:40:29.55	-05:08:18.4	HIP 42634	23.23
2026-05-16 00:00	08:40:30.66	-05:08:02.9	HIP 42634	22.87
2026-05-16 12:00	08:40:31.80	-05:07:47.6	HIP 42634	22.50
2026-05-17 00:00	08:40:32.97	-05:07:32.5	HIP 42634	22.14
2026-05-17 12:00	08:40:34.16	-05:07:17.5	HIP 42634	21.77
2026-05-18 00:00	08:40:35.39	-05:07:02.7	HIP 42634	21.41
2026-05-18 12:00	08:40:36.63	-05:06:48.1	HIP 42634	21.04
2026-05-19 00:00	08:40:37.91	-05:06:33.6	HIP 42634	20.67
2026-05-19 12:00	08:40:39.21	-05:06:19.4	HIP 42634	20.31
2026-05-20 00:00	08:40:40.54	-05:06:05.3	HIP 42634	19.94
2026-05-20 12:00	08:40:41.90	-05:05:51.3	HIP 42634	19.58
2026-05-21 00:00	08:40:43.29	-05:05:37.6	HIP 42634	19.22
2026-05-21 12:00	08:40:44.70	-05:05:24.0	HIP 42634	18.86
2026-05-22 00:00	08:40:46.13	-05:05:10.6	HIP 42634	18.50
2026-05-22 12:00	08:40:47.60	-05:04:57.3	HIP 42634	18.14
2026-05-23 00:00	08:40:49.09	-05:04:44.3	HIP 42634	17.79
2026-05-23 12:00	08:40:50.60	-05:04:31.4	HIP 42634	17.44
2026-05-24 00:00	08:40:52.15	-05:04:18.7	HIP 42634	17.09
2026-05-24 12:00	08:40:53.71	-05:04:06.2	HIP 42634	16.75
2026-05-25 00:00	08:40:55.31	-05:03:53.9	HIP 42634	16.42
2026-05-25 12:00	08:40:56.93	-05:03:41.7	HIP 42634	16.09
2026-05-26 00:00	08:40:58.57	-05:03:29.7	HIP 42634	15.77
2026-05-26 12:00	08:41:00.24	-05:03:17.9	HIP 42634	15.45
2026-05-27 00:00	08:41:01.93	-05:03:06.3	HIP 42634	15.15
2026-05-27 12:00	08:41:03.65	-05:02:54.9	HIP 42634	14.85
2026-05-28 00:00	08:41:05.40	-05:02:43.7	HIP 42634	14.57
2026-05-28 12:00	08:41:07.17	-05:02:32.6	HIP 42634	14.30
2026-05-29 00:00	08:41:08.96	-05:02:21.7	HIP 42634	14.04
2026-05-29 12:00	08:41:10.78	-05:02:11.0	HIP 42634	13.79
2026-05-30 00:00	08:41:12.62	-05:02:00.5	HIP 42634	13.56
2026-05-30 12:00	08:41:14.48	-05:01:50.2	HIP 42634	13.34
2026-05-31 00:00	08:41:16.37	-05:01:40.1	HIP 42634	13.15
2026-05-31 12:00	08:41:18.29	-05:01:30.2	HIP 42634	12.97
2026-06-01 00:00	08:41:20.23	-05:01:20.4	HIP 42634	12.82
2026-06-01 12:00	08:41:22.19	-05:01:10.8	HIP 42634	12.68
2026-06-02 00:00	08:41:24.17	-05:01:01.5	HIP 42634	12.57