 Comet Grigg–Mellish photographed byEdward Emerson Barnard on 13 April 1907 | |
| Discovery | |
|---|---|
| Discovered by | John E. Mellish John Grigg |
| Discovery date | 8 April 1907 |
| Designations | |
| 1907 II, 1907b[1] | |
| Orbital characteristics[3] | |
| Epoch | 18 April 1907 (JD 2417683.5) |
| Observation arc | 37 days[2] |
| Number of observations | 4 |
| Aphelion | 123.9 AU |
| Perihelion | 0.924 AU |
| Semi-major axis | 62.43 AU |
| Eccentricity | 0.985205 |
| Orbital period | ~490 years |
| Inclination | 109.95° |
| 190.47° | |
| Argument of periapsis | 328.60° |
| Last perihelion | 27 March 1907 |
| Next perihelion | ~2400 |
| TJupiter | -0.322 |
| EarthMOID | 0.003 AU |
| JupiterMOID | 1.351 AU |
| Comet total magnitude (M1) | 10.0[4] |
C/1907 G1 (Grigg–Mellish) is along-period comet discovered independently byJohn Grigg andJohn E. Mellish in April 1907. The comet has been identified as the parent body of the delta Pavonidsmeteor shower.
John Grigg, inNew Zealand, discovered a nebulous object near the starα Cae on 8 April 1907, however the discovery wasn't communicated quickly enough for observers in the southern hemisphere to confirm the discovery.[5] The comet was found independently by amateur astronomerJohn E. Mellish, fromMadison, Wisconsin, on 14 April. The comet had an apparent magnitude of 11 upon discovery.[6] The comet was also spotted byEdward Emerson Barnard in a photographic plate exposed on 13 April while he was searching for cometC/1907 E1 (Giacobini). The comet formed a trail 13.6 arcminutes long during the one hour the plate was exposed.[7] The comet was reported to have a coma two arcminutes across and a broad tail 8 arcminutes long on 16 April. The comet faded rapidly and it was difficult to measure with the 36-inch telescope ofLick Observatory on 7 May.[8]
The comet was found to have a similar orbit to cometC/1742 C1,[9] however comet Grigg–Mellish is intrinsically fainter than that comet. The comet's orbit passes very close to Earth, at a distance of 0.003 AU (450,000 km; 280,000 mi); Earth passes that point on 30 March. Due to the smallminimum orbit intersection distance, it was suggested to be a source of meteors with a radiant point atR.A. =20.63h,DEC = –60.4° and a speed of Vg = 59.0 km/s.[10]
Comet Grigg–Mellish has been identified as the parent body of the delta Pavonids meteor shower. The shower has azenithal hourly rate (ZHR) of 5 meteors per hour and peaks at March 31. An outburst was observed in 2019. The orbit of the meteors indicates that comet has an orbital period of447±80 years.[10]
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