C / 2006 M4 (SWAN)

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C / 2006 M4 (SWAN) [i]
Properties of the orbit ( animation )
Period:  November 10, 2006 ( JD 2,454,049.5)
Orbit type hyperbolic
s. Cape. Orbit
Numerical eccentricity 1,00019
Perihelion 0.783 AU
Inclination of the orbit plane 111.8 °
Perihelion September 28, 2006
Orbital velocity in the perihelion 47.6 km / s
history
Explorer Robert D. Matson, Michael Mattiazzo, SOHO
Date of discovery Early July 2006
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 2006 M4 (SWAN) is a comet that could be observed with the naked eye in 2006 .

Discovery and observation

At the beginning of July 2006, RD Matson from California and M. Mattiazzo from Australia reported the discovery of a possible comet, which they independently of one another on images of the SWAN experiment on the Solar and Heliospheric Observatory (SOHO) from June 20 to July 5th found. The discovery was confirmed shortly afterwards, as Terry Lovejoy from Queensland had already photographed the object with a digital camera on June 30th . Even Robert H. McNaught from the Siding Spring Observatory was the comet on July 12 with a 0.5-m Schmidt telescope pictures. At this point in time, the comet had a brightness of about 12 mag and was still 1.6  AU from the Sun and 2.3 AU from Earth . It was already showing a short tail .

The comet was last observed in Australia on July 20, before it was too close to the sun for observers on earth. In the second half of August he was observed with the cameras on board SOHO before the first time in mid-September in Spain at the dawn has been found. Shortly afterwards he was also observed in Japan . Although the comet was only slightly above the horizon, it was observed many times in September and October. At about 6 mag, its brightness remained so weak that it could only have been seen with the naked eye under the best of circumstances, but it was easy to observe with binoculars .

Shortly before mid-October, the comet was then found in the evening sky. An unexpected outbreak of brightness occurred during the night from October 23rd to 24th, whereby the brightness of the comet rose from 6 mag to about 4 mag in a very short time, so that the comet could easily be seen with open eyes in a dark environment.

In the following nights the brightness slowly decreased again, but the tail became more pronounced. At the beginning of November the brightness was around 6 mag again. As a result, some observers noticed an elongated shape of the coma , possibly the comet had broken, which could also have been the reason for its outbreak of brightness. It could be observed telescopically until the beginning of January 2007.

Scientific evaluation

The “forbidden” spectral lines of atomic oxygen on the comet were found with the 2.7 m telescope of the McDonald Observatory in Texas .

With the Cryogenic Echelle Spectrometer (CSHELL) on the 3 m telescope of the Infrared Telescope Facility on Mauna Kea and with observations on the 12 m radio telescope of the Arizona Radio Observatory (ARO) in Arizona , volatile organic substances were detected in the comet. In this H 2 O , CO , CH 3 OH , CH 4 and C 2 H 6 with cShell and additionally HCN measured and CS with ARO.

At the main observatory of the National Academy of Sciences of Ukraine , the evolution of the comet's plasma and dust tail was studied and a breakdown in the comet's tail was observed on October 27, 2006.

Orbit

For the comet, a temporary hyperbolic orbit could be determined from 1265 observation data over a period of 433 days , which is inclined by around 112 ° to the ecliptic . The comet's orbit is thus steeply inclined to the orbits of the planets and it runs its orbit in the opposite direction ( retrograde ) to them. At the point closest to the Sun ( perihelion ), which the comet passed on September 28, 2006, it was still around 117.1 million km from the Sun and was thus in the area between the orbits of Venus and Earth. On July 27th, it had already approached Mars within about 103.4 million km. On September 1st it passed Mercury at a distance of about 90.7 million km and on September 7th it passed Venus at a distance of about 47.9 million km. The closest approach to Earth was on October 25, except for a distance of about 149.2 million km (1.00 AU).

In the vicinity of the ascending node of its orbit, the comet even approached the earth's orbit to within 10.5 million km (0.07 AU) around August 22, 2006, but at that time the earth was exactly on the opposite side of the Sun.

According to the orbital elements, which are afflicted with a certain uncertainty, as they are specified in the JPL Small-Body Database and which do not take into account non-gravitational forces on the comet, the comet was still moving on an extremely elongated elliptical orbit long before it passed the inner solar system with an eccentricity of around 0.99984 and a semi-major axis of around 4900 AU, so that its period of revolution was around 345,000 years. The comet therefore came from the Oort cloud and possibly experienced its first passage through the inner solar system as a “dynamic young” comet. Due to the gravitational pull of the planets, especially due to the relatively close passages of Jupiter on March 29, 2006 at a distance of about 4 ¾ AU, on Saturn on July 5, 2006 in about 8 AU, and one more time at Jupiter on June 6, 2008 at a distance of about 4 ¾ AU, its orbital eccentricity was reduced to about 0.99941 and its semi-major axis to about 1320 AU, so that its orbital period is shortened to about 48,000 years.

See also

Web links

Commons : C / 2006 M4 (SWAN)  - collection of images, videos and audio files

Individual evidence

  1. ↑ GW Kronk: C / 2006 M4 (SWAN). In: Gary W. Kronks's Cometography. Accessed August 9, 2020 (English).
  2. ↑ Comet SWAN C / 2006 M4. In: kometen.info. Retrieved August 9, 2020 .
  3. ^ AL Cochran: Atomic oxygen in the comae of comets. In: Icarus. Volume 198, No. 1, 2008, pp. 181-188 doi: 10.1016 / j.icarus.2008.06.007 .
  4. ↑ MA DiSanti, GL Villanueva, SN Milam, LN Zack, BP Bonev, MJ Mumma, LM Ziurys, WM Anderson: A multi-wavelength study of parent volatile abundances in Comet C / 2006 M4 (SWAN). In: Icarus. Volume 203, No. 2, 2009, pp. 589-598 doi: 10.1016 / j.icarus.2009.05.026 .
  5. ↑ Yu. V. Sizonenko, PP Korsun: Physical characteristics of the plasma tail of comet C / 2006 M4 (SWAN). In: Kinematics and Physics of Celestial Bodies. Volume 25, 2009, Art. 249 doi: 10.3103 / S0884591309050031 .
  6. ↑ Yu. V. Sizonenko: Evolution of C / 2006 M4 (SWAN) comet tails. In: Kinematics and Physics of Celestial Bodies. Volume 28, 2012, pp. 9-14 doi: 10.3103 / S0884591312010072 .
  7. ↑ Yu. V. Sizonenko: DE-like event in the plasma tail of comet C / 2006 M4 (SWAN). In: Kinematics and Physics of Celestial Bodies. Volume 28, 2012, pp. 252-256 doi: 10.3103 / S0884591312050078 .
  8. ↑ C / 2006 M4 (SWAN) in the Small-Body Database of the Jet Propulsion Laboratory (English).Template: JPL Small-Body Database Browser / Maintenance / Alt
  9. ↑ A. Vitagliano: SOLEX 12.1. Retrieved July 9, 2020 .