Metadata

Parameter	Value
Designation	C/1984 N1 (Austin)
Type	C
Perihelion (tp_cal, UTC)	1984-08-12T03:17:25.103040Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:29:31Z
Obs used	100
NEO	-
M1	10.800
K1	15.750
PC	-

Osculating Elements

Parameter	Value
Epoch (epoch_cal, TDB)	1984-09-13.0000000
e	0.99984838
q (au)	0.291283
a (au)	1921.159758
i (deg)	164.153161
Ω (om, deg)	171.577849
ω (w, deg)	353.128957
M (ma, deg)	0.000373

Magnitude

Scatter + Global Linear

$$ M_a = (7.754 + 2.989\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter	Value
H0	7.754
n	2.989
gf	0.800
gb	-0.500
k	0.800
δ90	1.000

Parameter	Symbol	Range	Description
Absolute magnitude at 1 AU from Sun and Earth	H0	-5 to 20	Intrinsic brightness of the comet
Photometric slope parameter	n	2 to 6	Rate of brightness change with heliocentric distance
Forward scattering asymmetry factor	gf	0.8 to 1	Degree of forward scattering
Backward scattering asymmetry factor	gb	-1 to -0.5	Degree of backward scattering
Partitioning coefficient	k	0.8 to 1	Ratio between forward/backward scattering contributions
Dust-to-gas brightness ratio	δ90	1 to 10	Relative contribution of dust scattering to gas emission

Reference: EPSC-DPS2025-160

Residuals (Piecewise)

$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$

Start (UTC)	End (UTC)	a	b
1984-07-08	1984-07-30	+8.4930	+3.074
1984-07-30	1984-08-07	-0.7853	+0.326
1984-08-25	1984-09-14	-0.7139	-0.544
1984-09-14	1984-11-28	+5.1315	-0.517

log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)

Ephemeris

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-06-01 00:00	00:16:18.07	+05:57:07.7	HIP 1249	11.77
2026-06-01 12:00	00:16:18.72	+05:57:13.5	HIP 1249	11.96
2026-06-02 00:00	00:16:19.35	+05:57:19.3	HIP 1249	12.14
2026-06-02 12:00	00:16:19.98	+05:57:24.9	HIP 1249	12.32
2026-06-03 00:00	00:16:20.59	+05:57:30.5	HIP 1249	12.50
2026-06-03 12:00	00:16:21.18	+05:57:36.0	HIP 1249	12.68
2026-06-04 00:00	00:16:21.77	+05:57:41.4	HIP 1249	12.85
2026-06-04 12:00	00:16:22.34	+05:57:46.8	HIP 1249	13.02
2026-06-05 00:00	00:16:22.90	+05:57:52.1	HIP 1249	13.18
2026-06-05 12:00	00:16:23.44	+05:57:57.3	HIP 1249	13.34
2026-06-06 00:00	00:16:23.98	+05:58:02.4	HIP 1249	13.50
2026-06-06 12:00	00:16:24.50	+05:58:07.5	HIP 1249	13.65
2026-06-07 00:00	00:16:25.01	+05:58:12.5	HIP 1249	13.81
2026-06-07 12:00	00:16:25.51	+05:58:17.4	HIP 1249	13.95
2026-06-08 00:00	00:16:25.99	+05:58:22.2	HIP 1249	14.10
2026-06-08 12:00	00:16:26.46	+05:58:27.0	HIP 1249	14.24
2026-06-09 00:00	00:16:26.92	+05:58:31.7	HIP 1249	14.38
2026-06-09 12:00	00:16:27.36	+05:58:36.3	HIP 1249	14.51
2026-06-10 00:00	00:16:27.79	+05:58:40.8	HIP 1249	14.64
2026-06-10 12:00	00:16:28.21	+05:58:45.2	HIP 1249	14.77
2026-06-11 00:00	00:16:28.62	+05:58:49.6	HIP 1249	14.90
2026-06-11 12:00	00:16:29.01	+05:58:53.9	HIP 1249	15.02
2026-06-12 00:00	00:16:29.39	+05:58:58.1	HIP 1249	15.13
2026-06-12 12:00	00:16:29.76	+05:59:02.2	HIP 1249	15.25
2026-06-13 00:00	00:16:30.11	+05:59:06.3	HIP 1249	15.36
2026-06-13 12:00	00:16:30.45	+05:59:10.2	HIP 1249	15.47
2026-06-14 00:00	00:16:30.78	+05:59:14.1	HIP 1249	15.57
2026-06-14 12:00	00:16:31.09	+05:59:17.9	HIP 1249	15.67
2026-06-15 00:00	00:16:31.39	+05:59:21.6	HIP 1249	15.76
2026-06-15 12:00	00:16:31.67	+05:59:25.2	HIP 1249	15.86
2026-06-16 00:00	00:16:31.95	+05:59:28.8	HIP 1249	15.95
2026-06-16 12:00	00:16:32.21	+05:59:32.3	HIP 1249	16.03
2026-06-17 00:00	00:16:32.45	+05:59:35.6	HIP 1249	16.11
2026-06-17 12:00	00:16:32.69	+05:59:38.9	HIP 1249	16.19
2026-06-18 00:00	00:16:32.91	+05:59:42.2	HIP 1249	16.27
2026-06-18 12:00	00:16:33.11	+05:59:45.3	HIP 1249	16.34
2026-06-19 00:00	00:16:33.30	+05:59:48.3	HIP 1249	16.41
2026-06-19 12:00	00:16:33.48	+05:59:51.3	HIP 1249	16.47
2026-06-20 00:00	00:16:33.65	+05:59:54.2	HIP 1249	16.53
2026-06-20 12:00	00:16:33.80	+05:59:57.0	HIP 1249	16.59
2026-06-21 00:00	00:16:33.94	+05:59:59.7	HIP 1249	16.64
2026-06-21 12:00	00:16:34.06	+06:00:02.3	HIP 1249	16.70
2026-06-22 00:00	00:16:34.17	+06:00:04.8	HIP 1249	16.74