| Parameter |
Value |
| Designation |
C/2004 R2 (ASAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-10-07T21:32:12.880320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:42Z |
| Obs used |
66 |
| NEO |
- |
| M1 |
10.000 |
| K1 |
6.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2004-09-15.0000000 |
| e |
0.99999993 |
| q (au) |
0.112836 |
| a (au) |
1619082.250620 |
| i (deg) |
63.173694 |
| Ω (om, deg) |
182.463575 |
| ω (w, deg) |
5.353183 |
| M (ma, deg) |
360.000000 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.995 + 2.096\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.995 |
| n |
2.096 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-07-29 00:00 |
00:11:59.15 |
+01:44:05.6 |
HIP 870 |
27.46 |
| 2026-07-29 12:00 |
00:11:57.82 |
+01:43:56.8 |
HIP 870 |
27.33 |
| 2026-07-30 00:00 |
00:11:56.47 |
+01:43:47.9 |
HIP 870 |
27.20 |
| 2026-07-30 12:00 |
00:11:55.10 |
+01:43:38.8 |
HIP 870 |
27.07 |
| 2026-07-31 00:00 |
00:11:53.72 |
+01:43:29.6 |
HIP 870 |
26.95 |
| 2026-07-31 12:00 |
00:11:52.32 |
+01:43:20.3 |
HIP 870 |
26.82 |
| 2026-08-01 00:00 |
00:11:50.90 |
+01:43:10.9 |
HIP 870 |
26.71 |
| 2026-08-01 12:00 |
00:11:49.46 |
+01:43:01.4 |
HIP 870 |
26.59 |
| 2026-08-02 00:00 |
00:11:48.00 |
+01:42:51.8 |
HIP 870 |
26.48 |
| 2026-08-02 12:00 |
00:11:46.53 |
+01:42:42.1 |
HIP 870 |
26.38 |
| 2026-08-03 00:00 |
00:11:45.04 |
+01:42:32.2 |
HIP 870 |
26.28 |
| 2026-08-03 12:00 |
00:11:43.53 |
+01:42:22.2 |
HIP 870 |
26.18 |
| 2026-08-04 00:00 |
00:11:42.01 |
+01:42:12.1 |
HIP 870 |
26.09 |
| 2026-08-04 12:00 |
00:11:40.47 |
+01:42:01.9 |
HIP 870 |
26.01 |
| 2026-08-05 00:00 |
00:11:38.91 |
+01:41:51.6 |
HIP 870 |
25.93 |
| 2026-08-05 12:00 |
00:11:37.34 |
+01:41:41.2 |
HIP 870 |
25.85 |
| 2026-08-06 00:00 |
00:11:35.75 |
+01:41:30.7 |
HIP 870 |
25.79 |
| 2026-08-06 12:00 |
00:11:34.14 |
+01:41:20.1 |
HIP 870 |
25.73 |
| 2026-08-07 00:00 |
00:11:32.51 |
+01:41:09.3 |
HIP 870 |
25.67 |
| 2026-08-07 12:00 |
00:11:30.87 |
+01:40:58.5 |
HIP 870 |
25.63 |
| 2026-08-08 00:00 |
00:11:29.22 |
+01:40:47.5 |
HIP 870 |
25.59 |
| 2026-08-08 12:00 |
00:11:27.55 |
+01:40:36.4 |
HIP 870 |
25.56 |
| 2026-08-09 00:00 |
00:11:25.86 |
+01:40:25.3 |
HIP 870 |
25.53 |
| 2026-08-09 12:00 |
00:11:24.15 |
+01:40:14.0 |
HIP 870 |
25.52 |
| 2026-08-10 00:00 |
00:11:22.43 |
+01:40:02.6 |
HIP 870 |
25.51 |
| 2026-08-10 12:00 |
00:11:20.70 |
+01:39:51.1 |
HIP 870 |
25.51 |
| 2026-08-11 00:00 |
00:11:18.95 |
+01:39:39.5 |
HIP 870 |
25.52 |
| 2026-08-11 12:00 |
00:11:17.18 |
+01:39:27.8 |
HIP 870 |
25.54 |
| 2026-08-12 00:00 |
00:11:15.40 |
+01:39:16.1 |
HIP 870 |
25.57 |
| 2026-08-12 12:00 |
00:11:13.60 |
+01:39:04.2 |
HIP 870 |
25.61 |
| 2026-08-13 00:00 |
00:11:11.79 |
+01:38:52.2 |
HIP 870 |
25.66 |
| 2026-08-13 12:00 |
00:11:09.96 |
+01:38:40.1 |
HIP 870 |
25.72 |
| 2026-08-14 00:00 |
00:11:08.12 |
+01:38:27.9 |
HIP 870 |
25.79 |
| 2026-08-14 12:00 |
00:11:06.26 |
+01:38:15.6 |
HIP 870 |
25.87 |
| 2026-08-15 00:00 |
00:11:04.39 |
+01:38:03.2 |
HIP 870 |
25.96 |
| 2026-08-15 12:00 |
00:11:02.51 |
+01:37:50.8 |
HIP 870 |
26.06 |
| 2026-08-16 00:00 |
00:11:00.61 |
+01:37:38.2 |
HIP 870 |
26.17 |
| 2026-08-16 12:00 |
00:10:58.69 |
+01:37:25.5 |
HIP 870 |
26.29 |
| 2026-08-17 00:00 |
00:10:56.77 |
+01:37:12.8 |
HIP 870 |
26.42 |
| 2026-08-17 12:00 |
00:10:54.83 |
+01:37:00.0 |
HIP 870 |
26.57 |
| 2026-08-18 00:00 |
00:10:52.87 |
+01:36:47.0 |
HIP 870 |
26.72 |
| 2026-08-18 12:00 |
00:10:50.91 |
+01:36:34.0 |
HIP 870 |
26.88 |
| 2026-08-19 00:00 |
00:10:48.93 |
+01:36:20.9 |
HIP 870 |
27.06 |