 Comet Mrkos photographed from thePalomar Observatory on 25 August 1957 | |
| Discovery | |
|---|---|
| Discovered by | Antonín Mrkos |
| Discovery site | Lomnický štít, Czechoslovakia |
| Discovery date | 29 July 1957 |
| Designations | |
| 1957 V, 1957e[1] | |
| Orbital characteristics[2][3] | |
| Epoch | 10 March 1958 (JD 2436272.5) |
| Observation arc | 312 days |
| Number of observations | 16 |
| Aphelion | ~980 AU (inbound) ~640 AU (outbound) |
| Perihelion | 0.355 AU |
| Semi-major axis | ~540 AU |
| Eccentricity | 0.99934 |
| Orbital period | ~10,900 years (inbound) ~5,750 years (outbound) |
| Inclination | 93.957° |
| 68.324° | |
| Argument of periapsis | 40.319° |
| Mean anomaly | 0.018° |
| Last perihelion | 1 August 1957 |
| TJupiter | –0.041 |
| EarthMOID | 0.521 AU |
| JupiterMOID | 0.979 AU |
| Physical characteristics[4] | |
Mean diameter | ~24.0 km (14.9 mi) |
| Comet total magnitude (M1) | 4.0[5] |
| Comet nuclear magnitude (M2) | 12.2 |
| 1.0 (1957 apparition) | |
Comet Mrkos, formally known asC/1957 P1 (old style1957d), was anon-periodic comet discovered in 1957 byAntonín Mrkos. It was one of two bright comets that had their perihelion in 1957, the other beingComet Arend–Roland. Its peak magnitude was estimated to be around 1.0 and it has been characterised as agreat comet.[6][7]
The comet was discovered by Czech astronomer Antonin Mrkos bynaked eye at the observatory onLomnický štít,Czechoslovakia. He announced its discovery on August 2, 1957, but by that point it had already been discovered independently by others, with a report of observation from Japan dated July 29. However, the comet became known as comet Mrkos, as Mrkos' telegram was the first to arrive at the IAU. The comet was then near perihelion and itsapparent magnitude was estimated to be around 2.0.[8] By 4 August it had brightened to magnitude 1.0.[9]
At the time of discovery the comet was near perihelion and located nearPollux in the constellationGemini. It then moved north of the sun and was visible both in the evening and morning sky.[10] The comet gradually moved away from the sun and became a conspicuous object visible after sunset. The tail of the comet was estimated to be more than 5 degrees long. The comet had two tails, one that at the start was brighter and curved, and a straight one with knots that became brighter at the end of August and showed rapid changes in appearance.[8][9] From 10 August to 15 August the tail of the comet appeared striated.[11] The comet moved from the southern part ofUrsa Major toComa Berenices, while fading slowly. In September it crossed intoVirgo as a third-magnitude object;[10] it remained visible to the naked eye until the end of September.[8]
By the end of October 1957, the comet had moved close to the sun again and wasn't observable. It was recovered at the end of January 1958 and was last observed on 9 July 1958, when it was photographed as a diffuse 19th-magnitude object.[8]
Observation of the comet revealed the presence ofsodium[12] andcyanide[13] in its spectrum in the predicted values.
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