| Parameter |
Value |
| Designation |
C/2017 T1 (Heinze) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-02-21T16:59:46.164480Z |
| Orbit solution date (soln_date, UTC) |
2019-05-15T15:10:09Z |
| Obs used |
1005 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
14.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-12-14.0000000 |
| e |
1.00034579 |
| q (au) |
0.580655 |
| a (au) |
-1679.227553 |
| i (deg) |
96.833756 |
| Ω (om, deg) |
102.315945 |
| ω (w, deg) |
96.916279 |
| M (ma, deg) |
-0.000998 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.769 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.769 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.678 |
| k |
0.867 |
| δ90 |
10.000 |
| 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 |
| 2017-09-28 |
2017-12-30 |
-3.8045 |
+0.570 |
| 2017-12-30 |
2018-01-19 |
+22.8569 |
-1.570 |
| 2018-01-19 |
2018-02-21 |
+13.5047 |
-1.217 |
| 2018-02-23 |
2018-04-23 |
+0.3229 |
-0.952 |
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 |
07:36:40.79 |
-76:01:14.1 |
HIP 37114 |
16.71 |
| 2026-07-29 12:00 |
07:37:01.01 |
-76:01:28.1 |
HIP 37114 |
16.29 |
| 2026-07-30 00:00 |
07:37:21.19 |
-76:01:42.5 |
HIP 37114 |
15.95 |
| 2026-07-30 12:00 |
07:37:41.33 |
-76:01:57.5 |
HIP 37114 |
15.69 |
| 2026-07-31 00:00 |
07:38:01.44 |
-76:02:13.0 |
HIP 37114 |
15.52 |
| 2026-07-31 12:00 |
07:38:21.50 |
-76:02:29.0 |
HIP 37114 |
15.43 |
| 2026-08-01 00:00 |
07:38:41.53 |
-76:02:45.6 |
HIP 37114 |
15.43 |
| 2026-08-01 12:00 |
07:39:01.51 |
-76:03:02.6 |
HIP 37114 |
15.51 |
| 2026-08-02 00:00 |
07:39:21.45 |
-76:03:20.2 |
HIP 37114 |
15.69 |
| 2026-08-02 12:00 |
07:39:41.35 |
-76:03:38.3 |
HIP 37114 |
15.95 |
| 2026-08-03 00:00 |
07:40:01.20 |
-76:03:56.9 |
HIP 37114 |
16.28 |
| 2026-08-03 12:00 |
07:40:21.01 |
-76:04:16.1 |
HIP 37114 |
16.69 |
| 2026-08-04 00:00 |
07:40:40.77 |
-76:04:35.7 |
HIP 37114 |
17.17 |
| 2026-08-04 12:00 |
07:41:00.49 |
-76:04:55.9 |
HIP 37114 |
17.72 |
| 2026-08-05 00:00 |
07:41:20.16 |
-76:05:16.5 |
HIP 37114 |
18.32 |
| 2026-08-05 12:00 |
07:41:39.78 |
-76:05:37.7 |
HIP 37114 |
18.97 |
| 2026-08-06 00:00 |
07:41:59.35 |
-76:05:59.4 |
HIP 37114 |
19.67 |
| 2026-08-06 12:00 |
07:42:18.88 |
-76:06:21.6 |
HIP 37114 |
20.41 |
| 2026-08-07 00:00 |
07:42:38.35 |
-76:06:44.4 |
HIP 37114 |
21.18 |
| 2026-08-07 12:00 |
07:42:57.77 |
-76:07:07.6 |
HIP 37114 |
21.99 |
| 2026-08-08 00:00 |
07:43:17.14 |
-76:07:31.3 |
HIP 37114 |
22.83 |
| 2026-08-08 12:00 |
07:43:36.46 |
-76:07:55.6 |
HIP 38180 |
22.29 |
| 2026-08-09 00:00 |
07:43:55.72 |
-76:08:20.4 |
HIP 38180 |
21.34 |
| 2026-08-09 12:00 |
07:44:14.93 |
-76:08:45.6 |
HIP 38180 |
20.42 |
| 2026-08-10 00:00 |
07:44:34.08 |
-76:09:11.4 |
HIP 38180 |
19.55 |
| 2026-08-10 12:00 |
07:44:53.18 |
-76:09:37.7 |
HIP 38180 |
18.72 |
| 2026-08-11 00:00 |
07:45:12.22 |
-76:10:04.5 |
HIP 38180 |
17.95 |
| 2026-08-11 12:00 |
07:45:31.19 |
-76:10:31.8 |
HIP 38180 |
17.24 |
| 2026-08-12 00:00 |
07:45:50.11 |
-76:10:59.6 |
HIP 38180 |
16.60 |
| 2026-08-12 12:00 |
07:46:08.97 |
-76:11:27.8 |
HIP 38180 |
16.04 |
| 2026-08-13 00:00 |
07:46:27.76 |
-76:11:56.6 |
HIP 38180 |
15.56 |
| 2026-08-13 12:00 |
07:46:46.50 |
-76:12:25.9 |
HIP 38180 |
15.18 |
| 2026-08-14 00:00 |
07:47:05.17 |
-76:12:55.7 |
HIP 38180 |
14.89 |
| 2026-08-14 12:00 |
07:47:23.77 |
-76:13:26.0 |
HIP 38180 |
14.72 |
| 2026-08-15 00:00 |
07:47:42.31 |
-76:13:56.8 |
HIP 38180 |
14.66 |
| 2026-08-15 12:00 |
07:48:00.78 |
-76:14:28.0 |
HIP 38180 |
14.70 |
| 2026-08-16 00:00 |
07:48:19.18 |
-76:14:59.8 |
HIP 38180 |
14.86 |
| 2026-08-16 12:00 |
07:48:37.52 |
-76:15:32.0 |
HIP 38180 |
15.12 |
| 2026-08-17 00:00 |
07:48:55.78 |
-76:16:04.7 |
HIP 38180 |
15.49 |
| 2026-08-17 12:00 |
07:49:13.98 |
-76:16:37.9 |
HIP 38180 |
15.95 |
| 2026-08-18 00:00 |
07:49:32.10 |
-76:17:11.6 |
HIP 38180 |
16.49 |
| 2026-08-18 12:00 |
07:49:50.15 |
-76:17:45.7 |
HIP 38180 |
17.12 |
| 2026-08-19 00:00 |
07:50:08.13 |
-76:18:20.4 |
HIP 38180 |
17.81 |