| Parameter |
Value |
| Designation |
C/1913 Y1 (Delavan) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1914-10-26T18:27:07.724160Z |
| Orbit solution date (soln_date, UTC) |
2024-04-15T15:43:28Z |
| Obs used |
157 |
| NEO |
- |
| M1 |
4.800 |
| K1 |
4.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1914-03-15.0000000 |
| e |
1.00014579 |
| q (au) |
1.104401 |
| a (au) |
-7575.468577 |
| i (deg) |
68.042932 |
| Ω (om, deg) |
60.397252 |
| ω (w, deg) |
97.469440 |
| M (ma, deg) |
-0.000337 |
Magnitude
Scatter + Global Linear
$$
M_a = (-2.437 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-2.437 |
| n |
6.000 |
| 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) |
| 2026-09-20 00:00 |
01:52:22.10 |
-70:44:09.6 |
HIP 8834 |
26.79 |
| 2026-09-20 12:00 |
01:52:19.93 |
-70:44:17.2 |
HIP 8834 |
26.96 |
| 2026-09-21 00:00 |
01:52:17.74 |
-70:44:24.8 |
HIP 8834 |
27.12 |
| 2026-09-21 12:00 |
01:52:15.54 |
-70:44:32.2 |
HIP 8834 |
27.29 |
| 2026-09-22 00:00 |
01:52:13.33 |
-70:44:39.6 |
HIP 8834 |
27.45 |
| 2026-09-22 12:00 |
01:52:11.11 |
-70:44:46.8 |
HIP 8834 |
27.62 |
| 2026-09-23 00:00 |
01:52:08.87 |
-70:44:54.0 |
HIP 8834 |
27.78 |
| 2026-09-23 12:00 |
01:52:06.63 |
-70:45:01.0 |
HIP 8834 |
27.94 |
| 2026-09-24 00:00 |
01:52:04.37 |
-70:45:08.0 |
HIP 8834 |
28.11 |
| 2026-09-24 12:00 |
01:52:02.10 |
-70:45:14.9 |
HIP 8834 |
28.27 |
| 2026-09-25 00:00 |
01:51:59.82 |
-70:45:21.6 |
HIP 8834 |
28.43 |
| 2026-09-25 12:00 |
01:51:57.53 |
-70:45:28.3 |
HIP 8834 |
28.59 |
| 2026-09-26 00:00 |
01:51:55.23 |
-70:45:34.8 |
HIP 8834 |
28.75 |
| 2026-09-26 12:00 |
01:51:52.92 |
-70:45:41.3 |
HIP 8834 |
28.91 |
| 2026-09-27 00:00 |
01:51:50.60 |
-70:45:47.6 |
HIP 8834 |
29.07 |
| 2026-09-27 12:00 |
01:51:48.27 |
-70:45:53.9 |
HIP 8834 |
29.23 |
| 2026-09-28 00:00 |
01:51:45.93 |
-70:46:00.0 |
HIP 8834 |
29.39 |
| 2026-09-28 12:00 |
01:51:43.58 |
-70:46:06.0 |
HIP 8834 |
29.55 |
| 2026-09-29 00:00 |
01:51:41.21 |
-70:46:12.0 |
HIP 8834 |
29.70 |
| 2026-09-29 12:00 |
01:51:38.84 |
-70:46:17.8 |
HIP 8834 |
29.86 |
| 2026-09-30 00:00 |
01:51:36.46 |
-70:46:23.5 |
HIP 8834 |
30.01 |
| 2026-09-30 12:00 |
01:51:34.07 |
-70:46:29.1 |
HIP 8834 |
30.17 |
| 2026-10-01 00:00 |
01:51:31.68 |
-70:46:34.6 |
HIP 8834 |
30.32 |
| 2026-10-01 12:00 |
01:51:29.27 |
-70:46:40.0 |
HIP 8834 |
30.48 |
| 2026-10-02 00:00 |
01:51:26.85 |
-70:46:45.3 |
HIP 8834 |
30.63 |
| 2026-10-02 12:00 |
01:51:24.43 |
-70:46:50.5 |
HIP 8834 |
30.78 |
| 2026-10-03 00:00 |
01:51:22.00 |
-70:46:55.6 |
HIP 8834 |
30.93 |
| 2026-10-03 12:00 |
01:51:19.56 |
-70:47:00.6 |
HIP 8834 |
31.09 |
| 2026-10-04 00:00 |
01:51:17.11 |
-70:47:05.4 |
HIP 8834 |
31.24 |
| 2026-10-04 12:00 |
01:51:14.65 |
-70:47:10.2 |
HIP 8834 |
31.39 |
| 2026-10-05 00:00 |
01:51:12.19 |
-70:47:14.8 |
HIP 8834 |
31.54 |
| 2026-10-05 12:00 |
01:51:09.71 |
-70:47:19.3 |
HIP 8834 |
31.68 |
| 2026-10-06 00:00 |
01:51:07.24 |
-70:47:23.7 |
HIP 8834 |
31.83 |
| 2026-10-06 12:00 |
01:51:04.75 |
-70:47:28.0 |
HIP 8834 |
31.98 |
| 2026-10-07 00:00 |
01:51:02.26 |
-70:47:32.2 |
HIP 8834 |
32.13 |
| 2026-10-07 12:00 |
01:50:59.76 |
-70:47:36.3 |
HIP 8834 |
32.27 |
| 2026-10-08 00:00 |
01:50:57.25 |
-70:47:40.3 |
HIP 8834 |
32.42 |
| 2026-10-08 12:00 |
01:50:54.74 |
-70:47:44.1 |
HIP 8834 |
32.56 |
| 2026-10-09 00:00 |
01:50:52.22 |
-70:47:47.8 |
HIP 8834 |
32.70 |
| 2026-10-09 12:00 |
01:50:49.70 |
-70:47:51.4 |
HIP 8834 |
32.85 |
| 2026-10-10 00:00 |
01:50:47.17 |
-70:47:54.9 |
HIP 8834 |
32.99 |
| 2026-10-10 12:00 |
01:50:44.63 |
-70:47:58.3 |
HIP 8834 |
33.13 |
| 2026-10-11 00:00 |
01:50:42.09 |
-70:48:01.6 |
HIP 8834 |
33.27 |