C/1907 G1 (Grigg–Mellish)
 Comet Grigg-Mellish photographed by Edward Emerson Barnard on 13 April 1907 | |
| Discovery | |
|---|---|
| Discovered by | John E. Mellish John Grigg |
| Discovery date | 8 April 1907 |
| Designations | |
| 1907b | |
| Orbital characteristics[1] | |
| Epoch | 18 April 1907 (JD 2417683.5) |
| Number of observations | 4 |
| Aphelion | 62 AU |
| Perihelion | 0.92 AU |
| Semi-major axis | 31 AU |
| Eccentricity | 0.985 |
| Orbital period | 490 years |
| Inclination | 109.95° |
| 190.47° | |
| Argument of periapsis | 328.60° |
| Last perihelion | 27 March 1907 |
| TJupiter | -0.322 |
| Earth MOID | 0.003 AU |
C/1907 G1 (Grigg–Mellish) is a non-periodic comet discovered independently by John Grigg and John E. Mellish in April 1907. The comet has been identified as the parent body of the delta Pavonids meteor shower.
John Grigg, in New Zealand, discovered a nebulous object near alpha Caeli on 8 April 1907, however the discovery wasn't communicated quickly enough for observers in the southern hemisphere to confirm the discovery.[2] The comet was found independently by amateur astronomer John E. Mellish, from Madison, Wisconsin, on 14 April. The comet had an apparent magnitude of 11 upon discovery.[3] The comet was also spotted by Edward Emerson Barnard in a photographic plate exposed on 13 April while he was searching for comet Giacobini (1907a). The comet formed a trail 13.6 arcminutes long during the one hour the plate was exposed.[4] 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 of Lick Observatory on 7 May.[5]
The comet was found to have a similar orbit to comet C/1742 C1,[6] 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 (0.45 million km; 0.28 million mi); Earth passes that point on 30 March. Due to the small minimum intersection distance, it was suggested to be a source of meteors with a radiant point at R.A. = 309.5° and Decl. = −60.4° and a speed of Vg = 59.0 km/s.[7]
Comet Grigg–Mellish has been identified as the parent body of the delta Pavonids meteor shower. The shower has a zenithal 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 of 447 ± 80 years.[7]
References
[edit]- ^ "C/1907 G1 (Grigg-Mellish) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 12 December 2024.
- ^ Merfield, C. J. (January 1907). "On the comet 1907 b". Astronomische Nachrichten. 175 (10): 175–176. doi:10.1002/asna.19071751011.
- ^ "Our Astronomical Column". Nature. 75 (1955): 593–593. 1 April 1907. doi:10.1038/075593a0. ISSN 1476-4687.
- ^ Barnard, E. E. (January 1907). "Photographic observations of Mellish's comet 1907 b". Astronomische Nachrichten. 175 (23): 377–380. doi:10.1002/asna.19071752303.
- ^ Aitken, Robert Grant; Fath, Edward Arthur (1 January 1907). "Observations of Comet E 1906 (Kopff) ; Observation of Comet H 1906 ( Metcalf) ; Observations of Comet a 1907 (Giacobini) ; Observations of Comet B 1907 (Mellish) ; Observation of Comet C 1907 (Giacobini) ; Observations of Comet D 1907 (Daniel) ; Observations of Comet 1905 IV ( Kopff) ; Observations of (128) Nemesis". Lick Observatory Bulletin. 120: 148–151. doi:10.5479/ADS/bib/1907LicOB.4.148A. ISSN 0075-9317.
- ^ Weiss, Edmund (1 October 1907). "Über die Sichtbarkeitsverhältnisse der Kometen 1906 c (06 II), 1906 e (06 IV) (Kopff), 1906 h (06 VI) (Metcalf) und 1907 a,b und c vor ihrer Entdeckung". Astronomische Nachrichten. 176: 59. doi:10.1002/asna.19071760404. ISSN 0004-6337.
- ^ a b Jenniskens, P.; Lyytinen, E.; Baggaley, J. (September 2020). "An outburst of delta Pavonids and the orbit of parent comet C/1907 G1 (Grigg-Mellish)". Planetary and Space Science. 189: 104979. doi:10.1016/j.pss.2020.104979.
External links
[edit]- C/1907 G1 at the JPL Small-Body Database
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