| Parameter |
Value |
| Designation |
C/1999 F2 (Dalcanton) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-08-23T16:33:57.314880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:57Z |
| Obs used |
137 |
| NEO |
- |
| M1 |
7.800 |
| K1 |
7.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1999-09-29.0000000 |
| e |
0.99821105 |
| q (au) |
4.718078 |
| a (au) |
2637.338054 |
| i (deg) |
56.427410 |
| Ω (om, deg) |
210.297746 |
| ω (w, deg) |
352.352637 |
| M (ma, deg) |
0.002920 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.004 + 5.237\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.004 |
| n |
5.237 |
| gf |
1.000 |
| gb |
-0.608 |
| k |
0.800 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
23:02:14.44 |
+33:36:47.8 |
HIP 113618 |
30.03 |
| 2026-09-20 12:00 |
23:02:11.92 |
+33:36:30.4 |
HIP 113618 |
29.47 |
| 2026-09-21 00:00 |
23:02:09.40 |
+33:36:12.9 |
HIP 113618 |
28.92 |
| 2026-09-21 12:00 |
23:02:06.89 |
+33:35:55.1 |
HIP 113618 |
28.36 |
| 2026-09-22 00:00 |
23:02:04.38 |
+33:35:37.2 |
HIP 113618 |
27.80 |
| 2026-09-22 12:00 |
23:02:01.88 |
+33:35:19.0 |
HIP 113618 |
27.24 |
| 2026-09-23 00:00 |
23:01:59.39 |
+33:35:00.7 |
HIP 113618 |
26.68 |
| 2026-09-23 12:00 |
23:01:56.90 |
+33:34:42.3 |
HIP 113618 |
26.12 |
| 2026-09-24 00:00 |
23:01:54.42 |
+33:34:23.6 |
HIP 113618 |
25.56 |
| 2026-09-24 12:00 |
23:01:51.95 |
+33:34:04.8 |
HIP 113618 |
25.01 |
| 2026-09-25 00:00 |
23:01:49.49 |
+33:33:45.8 |
HIP 113618 |
24.45 |
| 2026-09-25 12:00 |
23:01:47.03 |
+33:33:26.7 |
HIP 113618 |
23.89 |
| 2026-09-26 00:00 |
23:01:44.58 |
+33:33:07.3 |
HIP 113618 |
23.34 |
| 2026-09-26 12:00 |
23:01:42.14 |
+33:32:47.8 |
HIP 113618 |
22.79 |
| 2026-09-27 00:00 |
23:01:39.71 |
+33:32:28.2 |
HIP 113618 |
22.23 |
| 2026-09-27 12:00 |
23:01:37.28 |
+33:32:08.4 |
HIP 113618 |
21.68 |
| 2026-09-28 00:00 |
23:01:34.87 |
+33:31:48.4 |
HIP 113618 |
21.13 |
| 2026-09-28 12:00 |
23:01:32.46 |
+33:31:28.2 |
HIP 113618 |
20.59 |
| 2026-09-29 00:00 |
23:01:30.06 |
+33:31:07.9 |
HIP 113618 |
20.04 |
| 2026-09-29 12:00 |
23:01:27.68 |
+33:30:47.4 |
HIP 113618 |
19.50 |
| 2026-09-30 00:00 |
23:01:25.30 |
+33:30:26.8 |
HIP 113618 |
18.96 |
| 2026-09-30 12:00 |
23:01:22.93 |
+33:30:06.0 |
HIP 113618 |
18.42 |
| 2026-10-01 00:00 |
23:01:20.57 |
+33:29:45.1 |
HIP 113618 |
17.88 |
| 2026-10-01 12:00 |
23:01:18.22 |
+33:29:24.0 |
HIP 113618 |
17.35 |
| 2026-10-02 00:00 |
23:01:15.88 |
+33:29:02.8 |
HIP 113618 |
16.82 |
| 2026-10-02 12:00 |
23:01:13.55 |
+33:28:41.4 |
HIP 113618 |
16.29 |
| 2026-10-03 00:00 |
23:01:11.23 |
+33:28:19.8 |
HIP 113618 |
15.77 |
| 2026-10-03 12:00 |
23:01:08.92 |
+33:27:58.1 |
HIP 113618 |
15.25 |
| 2026-10-04 00:00 |
23:01:06.62 |
+33:27:36.3 |
HIP 113618 |
14.74 |
| 2026-10-04 12:00 |
23:01:04.33 |
+33:27:14.3 |
HIP 113618 |
14.23 |
| 2026-10-05 00:00 |
23:01:02.06 |
+33:26:52.2 |
HIP 113618 |
13.73 |
| 2026-10-05 12:00 |
23:00:59.80 |
+33:26:29.9 |
HIP 113618 |
13.24 |
| 2026-10-06 00:00 |
23:00:57.55 |
+33:26:07.5 |
HIP 113618 |
12.75 |
| 2026-10-06 12:00 |
23:00:55.31 |
+33:25:45.0 |
HIP 113618 |
12.27 |
| 2026-10-07 00:00 |
23:00:53.08 |
+33:25:22.3 |
HIP 113618 |
11.80 |
| 2026-10-07 12:00 |
23:00:50.86 |
+33:24:59.5 |
HIP 113618 |
11.34 |
| 2026-10-08 00:00 |
23:00:48.66 |
+33:24:36.5 |
HIP 113618 |
10.90 |
| 2026-10-08 12:00 |
23:00:46.47 |
+33:24:13.4 |
HIP 113618 |
10.46 |
| 2026-10-09 00:00 |
23:00:44.29 |
+33:23:50.2 |
HIP 113618 |
10.04 |
| 2026-10-09 12:00 |
23:00:42.13 |
+33:23:26.9 |
HIP 113618 |
9.64 |
| 2026-10-10 00:00 |
23:00:39.98 |
+33:23:03.4 |
HIP 113618 |
9.26 |
| 2026-10-10 12:00 |
23:00:37.84 |
+33:22:39.8 |
HIP 113618 |
8.90 |
| 2026-10-11 00:00 |
23:00:35.72 |
+33:22:16.1 |
HIP 113618 |
8.56 |