| Discovery[1] | |
|---|---|
| Discovered by | Andrea Boattini |
| Discovery site | Mt. Lemmon Survey (G96) |
| Discovery date | 20 November 2007 |
| Designations | |
| CK07W010[1] | |
| Orbital characteristics[2][3][4] | |
| Epoch | 25 May 2008 (JD 2454611.5) |
| Observation arc | 597 days (1.63 years) |
| Number of observations | 1,639 |
| Aphelion | ~3,163 AU |
| Perihelion | 0.84972 AU |
| Semi-major axis | ~1,582 AU |
| Eccentricity | 1.00015 |
| Orbital period | ~63,000 years |
| Inclination | 9.8903° |
| 334.53° | |
| Argument of periapsis | 306.55° |
| Last perihelion | 24 June 2008 |
| EarthMOID | 0.0179 AU |
| JupiterMOID | 0.0160 AU |
| Physical characteristics[6][7] | |
Mean radius | 0.65±0.03 km |
| Mass | 4.6×1011 kg |
Meandensity | 440±60 kg/m3 |
| Comet total magnitude (M1) | 15.0 |
| 5.0 (2008 apparition)[5] | |
C/2007 W1 (Boattini) is anon-periodic comet discovered on 20 November 2007, byAndrea Boattini at theMt. Lemmon Survey.[1] At the peak the comet had anapparent magnitude around 5.[5]
On 3 April 2008, when C/2007 W1 was 0.66AU from the Earth and 1.7AU from the Sun, thecoma (expanding tenuous dust atmosphere) of the comet was estimated to be as large as 10arcminutes.[8] This made the coma roughly 90,000 km (56,000 mi) in diameter.[a]
On 30 April 2008, Alexandre Amorim reported that the comet was a magnitude 7.3 object as seen in 10 × 50 binoculars.[9] By 8 May 2008, David Seargent noted that it brightened up to magnitude 6.4 in the naked eye.[10] It was located within the constellationPyxis on 20 May 2008.[11]
On 12 June 2008, the comet passed within about 0.21005 AU (31,423,000 km; 19,525,000 mi) of the Earth.[3] The comet came toperihelion on 24 June 2008 at a distance of 0.8497 AU (127.11 million km).[3]
The comet has an observationarc of 597 days[3] allowing a good estimate of the orbit. The orbit of a long-period comet is properly obtained when theosculating orbit is computed at anepoch after leaving the planetary region and is calculated with respect to thecenter of mass of the Solar System. UsingJPL Horizons, the barycentric orbital elements for epoch 2020-Jan-01 generate asemi-major axis of 1,582 AU, anapoapsis distance of 3,163 AU, and a period of approximately 63,000 years.[2][4]
A 2022 study calculated that it has aminimum orbit intersection distance of around 0.061 AU (9.1 million km) and 0.044 AU (6.6 million km) with55637 Uni and(307762) 2003 VC1 respectively.[12]
Before entering the planetary region, C/2007 W1 had ahyperbolic trajectory.[2] The comet was probably in the outerOort cloud with a loosely bound chaotic orbit that was easily perturbed bypassing stars.
Ameteor shower known as theDaytime Craterids has been associated with C/2007 W1, thus becoming the first hyperbolic comet associated with a meteor shower. The meteor shower produced daytime outbursts in 2003 and 2009, with aZenithal Hourly Rate of over 30 meteors per hour observed with radar.[13]
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