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)
2026-07-29 00:00	00:16:05.22	+05:59:08.8	HIP 1249	10.79
2026-07-29 12:00	00:16:04.34	+05:59:04.7	HIP 1249	10.60
2026-07-30 00:00	00:16:03.46	+05:59:00.6	HIP 1249	10.41
2026-07-30 12:00	00:16:02.56	+05:58:56.4	HIP 1249	10.23
2026-07-31 00:00	00:16:01.66	+05:58:52.1	HIP 1249	10.04
2026-07-31 12:00	00:16:00.74	+05:58:47.7	HIP 1249	9.85
2026-08-01 00:00	00:15:59.80	+05:58:43.2	HIP 1249	9.66
2026-08-01 12:00	00:15:58.86	+05:58:38.7	HIP 1249	9.47
2026-08-02 00:00	00:15:57.91	+05:58:34.1	HIP 1249	9.28
2026-08-02 12:00	00:15:56.94	+05:58:29.3	HIP 1249	9.09
2026-08-03 00:00	00:15:55.97	+05:58:24.5	HIP 1249	8.90
2026-08-03 12:00	00:15:54.98	+05:58:19.7	HIP 1249	8.71
2026-08-04 00:00	00:15:53.98	+05:58:14.7	HIP 1249	8.52
2026-08-04 12:00	00:15:52.97	+05:58:09.7	HIP 1249	8.34
2026-08-05 00:00	00:15:51.95	+05:58:04.5	HIP 1249	8.15
2026-08-05 12:00	00:15:50.91	+05:57:59.3	HIP 1249	7.97
2026-08-06 00:00	00:15:49.87	+05:57:54.1	HIP 1249	7.79
2026-08-06 12:00	00:15:48.81	+05:57:48.7	HIP 1249	7.62
2026-08-07 00:00	00:15:47.75	+05:57:43.2	HIP 1249	7.45
2026-08-07 12:00	00:15:46.67	+05:57:37.7	HIP 1249	7.28
2026-08-08 00:00	00:15:45.59	+05:57:32.1	HIP 1249	7.12
2026-08-08 12:00	00:15:44.49	+05:57:26.4	HIP 1249	6.97
2026-08-09 00:00	00:15:43.38	+05:57:20.7	HIP 1249	6.82
2026-08-09 12:00	00:15:42.26	+05:57:14.8	HIP 1249	6.68
2026-08-10 00:00	00:15:41.13	+05:57:08.9	HIP 1249	6.55
2026-08-10 12:00	00:15:39.99	+05:57:02.9	HIP 1249	6.43
2026-08-11 00:00	00:15:38.84	+05:56:56.8	HIP 1249	6.32
2026-08-11 12:00	00:15:37.68	+05:56:50.7	HIP 1249	6.22
2026-08-12 00:00	00:15:36.51	+05:56:44.4	HIP 1249	6.13
2026-08-12 12:00	00:15:35.33	+05:56:38.1	HIP 1249	6.06
2026-08-13 00:00	00:15:34.14	+05:56:31.7	HIP 1249	6.00
2026-08-13 12:00	00:15:32.94	+05:56:25.3	HIP 1249	5.96
2026-08-14 00:00	00:15:31.73	+05:56:18.8	HIP 1249	5.93
2026-08-14 12:00	00:15:30.51	+05:56:12.1	HIP 1249	5.92
2026-08-15 00:00	00:15:29.28	+05:56:05.5	HIP 1249	5.93
2026-08-15 12:00	00:15:28.04	+05:55:58.7	HIP 1249	5.96
2026-08-16 00:00	00:15:26.80	+05:55:51.9	HIP 1249	6.00
2026-08-16 12:00	00:15:25.54	+05:55:45.0	HIP 1249	6.06
2026-08-17 00:00	00:15:24.27	+05:55:38.0	HIP 1249	6.14
2026-08-17 12:00	00:15:23.00	+05:55:31.0	HIP 1249	6.24
2026-08-18 00:00	00:15:21.71	+05:55:23.8	HIP 1249	6.35
2026-08-18 12:00	00:15:20.42	+05:55:16.7	HIP 1249	6.48
2026-08-19 00:00	00:15:19.12	+05:55:09.4	HIP 1249	6.63