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)
2026-09-20 00:00	00:13:42.01	+05:45:25.4	HIP 1050	11.89
2026-09-20 12:00	00:13:40.36	+05:45:14.9	HIP 1050	11.46
2026-09-21 00:00	00:13:38.70	+05:45:04.3	HIP 1050	11.04
2026-09-21 12:00	00:13:37.05	+05:44:53.7	HIP 1050	10.61
2026-09-22 00:00	00:13:35.39	+05:44:43.1	HIP 1050	10.18
2026-09-22 12:00	00:13:33.73	+05:44:32.5	HIP 1050	9.76
2026-09-23 00:00	00:13:32.07	+05:44:21.8	HIP 1050	9.34
2026-09-23 12:00	00:13:30.41	+05:44:11.2	HIP 1050	8.92
2026-09-24 00:00	00:13:28.75	+05:44:00.5	HIP 1050	8.50
2026-09-24 12:00	00:13:27.09	+05:43:49.7	HIP 1050	8.09
2026-09-25 00:00	00:13:25.43	+05:43:39.0	HIP 1050	7.68
2026-09-25 12:00	00:13:23.76	+05:43:28.2	HIP 1050	7.27
2026-09-26 00:00	00:13:22.10	+05:43:17.4	HIP 1050	6.87
2026-09-26 12:00	00:13:20.44	+05:43:06.6	HIP 1050	6.48
2026-09-27 00:00	00:13:18.77	+05:42:55.8	HIP 1050	6.09
2026-09-27 12:00	00:13:17.11	+05:42:45.0	HIP 1050	5.72
2026-09-28 00:00	00:13:15.45	+05:42:34.1	HIP 1050	5.35
2026-09-28 12:00	00:13:13.78	+05:42:23.2	HIP 1050	5.00
2026-09-29 00:00	00:13:12.12	+05:42:12.3	HIP 1050	4.67
2026-09-29 12:00	00:13:10.46	+05:42:01.4	HIP 1050	4.35
2026-09-30 00:00	00:13:08.80	+05:41:50.5	HIP 1050	4.07
2026-09-30 12:00	00:13:07.14	+05:41:39.6	HIP 1050	3.81
2026-10-01 00:00	00:13:05.48	+05:41:28.7	HIP 1050	3.59
2026-10-01 12:00	00:13:03.82	+05:41:17.7	HIP 1050	3.42
2026-10-02 00:00	00:13:02.16	+05:41:06.7	HIP 1050	3.31
2026-10-02 12:00	00:13:00.51	+05:40:55.8	HIP 1050	3.25
2026-10-03 00:00	00:12:58.85	+05:40:44.8	HIP 1050	3.25
2026-10-03 12:00	00:12:57.20	+05:40:33.8	HIP 1050	3.31
2026-10-04 00:00	00:12:55.55	+05:40:22.8	HIP 1050	3.43
2026-10-04 12:00	00:12:53.90	+05:40:11.8	HIP 1050	3.61
2026-10-05 00:00	00:12:52.25	+05:40:00.8	HIP 1050	3.83
2026-10-05 12:00	00:12:50.60	+05:39:49.8	HIP 1050	4.08
2026-10-06 00:00	00:12:48.96	+05:39:38.8	HIP 1050	4.37
2026-10-06 12:00	00:12:47.32	+05:39:27.8	HIP 1050	4.68
2026-10-07 00:00	00:12:45.68	+05:39:16.8	HIP 1050	5.01
2026-10-07 12:00	00:12:44.04	+05:39:05.7	HIP 1050	5.36
2026-10-08 00:00	00:12:42.41	+05:38:54.7	HIP 1050	5.72
2026-10-08 12:00	00:12:40.78	+05:38:43.7	HIP 1050	6.09
2026-10-09 00:00	00:12:39.15	+05:38:32.7	HIP 1050	6.47
2026-10-09 12:00	00:12:37.53	+05:38:21.7	HIP 1050	6.86
2026-10-10 00:00	00:12:35.90	+05:38:10.7	HIP 1050	7.25
2026-10-10 12:00	00:12:34.29	+05:37:59.6	HIP 1050	7.65
2026-10-11 00:00	00:12:32.67	+05:37:48.6	HIP 1050	8.05