C / 2011 L4 (PANSTARRS)

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C / 2011 L4 (PANSTARRS) [i]
C / 2011 L4 on May 26, 2013
C / 2011 L4 on May 26, 2013
Properties of the orbit ( animation )
Epoch:  March 14, 2013 ( JD 2,456,365.5)
Orbit type hyperbolic
s. Cape. Orbit
Numerical eccentricity 1.000033
Perihelion 0.302 AU
Inclination of the orbit plane 84.2 °
Perihelion March 10, 2013
Orbital velocity in the perihelion 76.7 km / s
history
Explorer Pan-STARRS
Date of discovery June 6, 2011
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 2011 L4 (PANSTARRS) is a comet that was visible to the naked eye in Europe in March / April 2013 . Due to its brightness, it is counted among the " Great Comets ".

Discovery and observation

The comet was first discovered by a team led by R. Wainscoat on images taken on June 6, 2011 as part of the Pan-STARRS program with the 1.8 m PS1 telescope on Haleakalā (Hawaii). Its brightness at this point was about 19.5 mag and it was about 7.9  AU from the Sun , beyond the orbit of the planet Jupiter . The following day, the discovery was confirmed with further images from the 3.6 m Canada-France-Hawaii Telescope on Mauna Kea . The comet was subsequently found on several photographs taken by various astronomers on May 24th and 30th. The Pan-STARRS telescope had already captured the comet on images taken on May 21.

First calculations of the comet's orbit already showed that it would come relatively close to the sun and that it would thus possibly become a bright comet. This made him interesting and he was widely watched. At the end of March 2012 the brightness had already reached 14.5 mag and the comet could then be visually observed with large amateur telescopes until the beginning of October 2012, when its brightness was 10 mag . When he emerged from dusk in mid-December, he was first observed in Australia . In early February 2013, the brightness rose above 6 mag and the comet was first observed with the naked eye in Australia at dawn on February 7th in Australia . In the following weeks the comet could be observed first in the southern hemisphere in the morning and evening sky, from the beginning of March worldwide in the evening twilight. Brightnesses of down to -1 mag and a tail length of 0.25 ° were reported.

After a brief interruption while passing the sun, the comet could be observed again from mid-March at dusk at a brightness of 1 mag, it showed a 3 ° long tail. The comet moved further into the northern sky so that it could be observed better and better in the northern hemisphere , at the same time its brightness decreased again, so that it could be seen with the naked eye for the last time at the end of April. At the beginning of April it had been observed close to the Andromeda Galaxy and on May 27th it approached the North Star up to an angular distance of about 5 °. In June the brightness had dropped to around 9 mag, but the comet could still be telescoped until August 2014.

Scientific evaluation

Photometric measurements were carried out on the comet at a distance of more than 4 AU from the sun , with which the rate of dust loss and the comet's radius could be measured.

With the Solar Wind Anisotropies (SWAN) camera on board the Solar and Heliospheric Observatory (SOHO), recordings were made from the end of January to the end of April 2013, from which the production rate of water depending on the distance from the sun of the comet was derived. A higher production rate was found before the perihelion than after it.

With the ACIS spectrometer on the Chandra X-ray telescope, the emission of the comet was observed in April 2013; a region that only emits diffuse X-ray light was detected.

At the Osservatorio astronomico GV Schiaparelli on the Campo dei Fiori mountain in Italy , high-resolution spectra of the cometary light were obtained from which the presence of sodium and potassium and their relative relationship to one another were determined. Lithium was not found.

A lower value for the diameter of the comet of 2.4 ± 0.3 km could be derived from the light curve of the comet and that it was a "dynamically young" and active comet from the Oort cloud .

Orbit

For the comet, a temporary hyperbolic orbit could be determined from 5413 observation data over a period of 3 ¼ years , which is inclined by around 84 ° to the ecliptic . The comet's orbit is almost perpendicular to the planets of the planets. At the point closest to the Sun ( perihelion ), which the comet passed on March 10, 2013, it was about 45.1 million km from the Sun and was slightly within the range of the orbit of Mercury . On January 28th it had already approached Venus up to about 109.6 million km and on March 4th it passed Mercury at a distance of about 84.3 million km. It came closest to Earth on March 5, at a distance of about 1.10 AU / 164.1 million km. After the passage of the perihelion, there was another passage past Venus on March 12th at a distance of about 112.5 million km and on March 13th the comet approached Mars up to about 189.3 million km.

After the orbital elements with a certain uncertainty and without taking into account non-gravitational forces on the comet, its orbit still had an eccentricity of slightly below 1.0000 long before the passage through the inner solar system in 2013 , its orbit was almost parabolic . With a semi-major axis of over 30,000 AU (about half a light year ), its orbital period was in the range of several million years. The comet came from the Oort cloud and possibly experienced its first passage through the inner solar system as a “dynamic young” comet. This could also explain its strong increase in brightness when approaching the sun. Due to the gravitational pull of the planets, in particular due to the relatively close passages of Saturn on February 11, 2012 at a distance of about 6, AU, at Jupiter on March 16, 2013 in about 4 ¾ AU, and again at Saturn on January 16, 2015 at a distance of about 7 ¼ AU, its orbital eccentricity was reduced to about 0.99987 and its semi-major axis to about 2250 AU, so that its orbital period is shortened to about 107,000 years.

See also

Web links

Commons : C / 2011 L4 (PANSTARRS)  - Collection of images, videos and audio files
 Wikinews: Comet PANSTARRS in observation position  - message

Individual evidence

  1. ^ GW Kronk: C / 2011 L4 (PANSTARRS). In: Gary W. Kronk's Cometography. Retrieved July 17, 2020 .
  2. ↑ Comet PANSTARRS C / 2011 L4. In: kometen.info. June 6, 2013, accessed July 17, 2020 .
  3. ↑ O. Ivanova, S. Borysenko, A. Golovin: Photometry of Comet C / 2011 L4 (PANSTARRS) at 4.4-4.2 AU heliocentric distances. In: Icarus. Volume 227, 2014, pp. 202–205 doi: 10.1016 / j.icarus.2013.08.026 .
  4. ↑ MR Combi, J.-L. Bertaux, E. Quémerais, S. Ferron, JTT Mäkinen, G. Aptekar: Water Production in Comets C / 2011 L4 (PanSTARRS) and C / 2012 F6 (Lemmon) from Observations with SOHO / SWAN. In: The Astronomical Journal. Volume 147, No. 6, 2014, pp. 1–7 doi: 10.1088 / 0004-6256 / 147/6/126 . ( PDF; 550 kB )
  5. ↑ B. Snios, V. Kharchenko, CM Lisse, SJ Wolk, K. Dennerl, MR Combi: CHANDRA Observations of Comets C / 2012 S1 (ISON) and C / 2011 L4 (PanSTARRS). In: The Astrophysical Journal. Volume 818, No. 2, 2016, pp. 1–10 doi: 10.3847 / 0004-637X / 818/2/199 . ( PDF; 1.12 MB )
  6. ↑ M. Fulle, P. Molaro, L. Buzzi, P. Valisa: Potassium Detection and lithium depletion in Comets C / 2011 L4 (PanSTARRS) and C / 1965 S1 (Ikeya-Seki). In: The Astrophysical Journal Letters. Volume 771, L21, 2013, pp. 1-4 doi: 10.1088 / 2041-8205 / 771/2 / L21 . ( PDF; 371 kB )
  7. ^ I. Ferrín: The location of Oort Cloud comets C / 2011 L4 Panstarrs and C / 2012 S1 ISON on a comet evolutionary diagram. In: Monthly Notices of the Royal Astronomical Society. Volume 442, No. 2, 2014, pp. 1731–1754 doi: 10.1093 / mnras / stu820 . ( PDF; 8.31 MB )
  8. ↑ C / 2011 L4 (PANSTARRS) in the Small-Body Database of the Jet Propulsion Laboratory .Template: JPL Small-Body Database Browser / Maintenance / Alt
  9. ↑ SOLEX 12.1 by A. Vitagliano. Retrieved July 9, 2020 .