| 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) |
| 2026-05-12 00:00 |
00:11:25.36 |
+01:40:49.5 |
HIP 870 |
25.12 |
| 2026-05-12 12:00 |
00:11:27.02 |
+01:41:00.1 |
HIP 870 |
25.15 |
| 2026-05-13 00:00 |
00:11:28.68 |
+01:41:10.7 |
HIP 870 |
25.18 |
| 2026-05-13 12:00 |
00:11:30.31 |
+01:41:21.1 |
HIP 870 |
25.23 |
| 2026-05-14 00:00 |
00:11:31.93 |
+01:41:31.4 |
HIP 870 |
25.28 |
| 2026-05-14 12:00 |
00:11:33.54 |
+01:41:41.6 |
HIP 870 |
25.34 |
| 2026-05-15 00:00 |
00:11:35.12 |
+01:41:51.7 |
HIP 870 |
25.41 |
| 2026-05-15 12:00 |
00:11:36.70 |
+01:42:01.7 |
HIP 870 |
25.48 |
| 2026-05-16 00:00 |
00:11:38.26 |
+01:42:11.7 |
HIP 870 |
25.56 |
| 2026-05-16 12:00 |
00:11:39.80 |
+01:42:21.5 |
HIP 870 |
25.64 |
| 2026-05-17 00:00 |
00:11:41.32 |
+01:42:31.2 |
HIP 870 |
25.73 |
| 2026-05-17 12:00 |
00:11:42.83 |
+01:42:40.8 |
HIP 870 |
25.83 |
| 2026-05-18 00:00 |
00:11:44.32 |
+01:42:50.3 |
HIP 870 |
25.93 |
| 2026-05-18 12:00 |
00:11:45.80 |
+01:42:59.7 |
HIP 870 |
26.04 |
| 2026-05-19 00:00 |
00:11:47.26 |
+01:43:09.0 |
HIP 870 |
26.15 |
| 2026-05-19 12:00 |
00:11:48.70 |
+01:43:18.2 |
HIP 870 |
26.26 |
| 2026-05-20 00:00 |
00:11:50.13 |
+01:43:27.2 |
HIP 870 |
26.38 |
| 2026-05-20 12:00 |
00:11:51.54 |
+01:43:36.2 |
HIP 870 |
26.50 |
| 2026-05-21 00:00 |
00:11:52.93 |
+01:43:45.1 |
HIP 870 |
26.62 |
| 2026-05-21 12:00 |
00:11:54.31 |
+01:43:53.8 |
HIP 870 |
26.75 |
| 2026-05-22 00:00 |
00:11:55.67 |
+01:44:02.4 |
HIP 870 |
26.88 |
| 2026-05-22 12:00 |
00:11:57.01 |
+01:44:11.0 |
HIP 870 |
27.02 |
| 2026-05-23 00:00 |
00:11:58.33 |
+01:44:19.4 |
HIP 870 |
27.15 |
| 2026-05-23 12:00 |
00:11:59.64 |
+01:44:27.7 |
HIP 870 |
27.29 |
| 2026-05-24 00:00 |
00:12:00.93 |
+01:44:35.9 |
HIP 870 |
27.43 |
| 2026-05-24 12:00 |
00:12:02.20 |
+01:44:44.0 |
HIP 870 |
27.57 |
| 2026-05-25 00:00 |
00:12:03.45 |
+01:44:51.9 |
HIP 870 |
27.72 |
| 2026-05-25 12:00 |
00:12:04.69 |
+01:44:59.8 |
HIP 870 |
27.86 |
| 2026-05-26 00:00 |
00:12:05.91 |
+01:45:07.5 |
HIP 870 |
28.01 |
| 2026-05-26 12:00 |
00:12:07.11 |
+01:45:15.2 |
HIP 870 |
28.15 |
| 2026-05-27 00:00 |
00:12:08.29 |
+01:45:22.7 |
HIP 870 |
28.30 |
| 2026-05-27 12:00 |
00:12:09.46 |
+01:45:30.1 |
HIP 870 |
28.45 |
| 2026-05-28 00:00 |
00:12:10.60 |
+01:45:37.4 |
HIP 870 |
28.60 |
| 2026-05-28 12:00 |
00:12:11.73 |
+01:45:44.5 |
HIP 870 |
28.75 |
| 2026-05-29 00:00 |
00:12:12.84 |
+01:45:51.6 |
HIP 870 |
28.89 |
| 2026-05-29 12:00 |
00:12:13.94 |
+01:45:58.5 |
HIP 870 |
29.04 |
| 2026-05-30 00:00 |
00:12:15.01 |
+01:46:05.3 |
HIP 870 |
29.19 |
| 2026-05-30 12:00 |
00:12:16.07 |
+01:46:12.0 |
HIP 870 |
29.34 |
| 2026-05-31 00:00 |
00:12:17.10 |
+01:46:18.6 |
HIP 870 |
29.49 |
| 2026-05-31 12:00 |
00:12:18.12 |
+01:46:25.1 |
HIP 870 |
29.63 |
| 2026-06-01 00:00 |
00:12:19.12 |
+01:46:31.4 |
HIP 870 |
29.78 |
| 2026-06-01 12:00 |
00:12:20.10 |
+01:46:37.6 |
HIP 870 |
29.92 |
| 2026-06-02 00:00 |
00:12:21.07 |
+01:46:43.7 |
HIP 870 |
30.07 |