C / 1907 L2 (Daniel)

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C / 1907 L2 (Daniel) [i]
Comet Daniel on August 4, 1907
Comet Daniel on August 4, 1907
Properties of the orbit ( animation )
Period:  September 22nd, 1907 ( JD 2,417,840.5)
Orbit type long-period
Numerical eccentricity 0.9988
Perihelion 0.512 AU
Aphelion 849 AU
Major semi-axis 425 AU
Sidereal period ~ 8750 a
Inclination of the orbit plane 9.0 °
Perihelion 4th September 1907
Orbital velocity in the perihelion 58.8 km / s
history
Explorer Zaccheus Daniel
Date of discovery June 9, 1907
Older name 1907 IV, 1907d
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1907 L2 (Daniel) is a comet that could be seen with the naked eye in 1907 .

Discovery and observation

The comet was on the morning of June 9 1907 by Zaccheus Daniel with a 6-inch - telescope at the observatory in Princeton (New Jersey) discovered. The comet was only a few degrees above the planet Saturn in the eastern sky . It was Daniel's first comet discovery, followed by two more in 1909.

From mid-July, the comet could then also be seen with the naked eye for two months. At that time it had a brightness of 4 mag and a narrow tail about 5 ° long. At the beginning of August the brightness had risen to 3 mag, the tail had reached a length of 15 °. At the beginning of September its brightness reached 2 mag and the tail was still 5-6 ° long. The whole time the comet could only be seen just above the horizon at dawn. After the comet had reached its closest approach to the sun on October 3rd with a westerly elongation of almost 16 ° and then moved away from it again , it could be observed again in the morning sky from the beginning of November , but because of it its low brightness only with optical instruments.

Overall, the observations of the comet extended over a year; the last position was determined on June 27, 1908.

The comet reached a maximum brightness of 2 mag.

Scientific evaluation

The development of astrophotography around the beginning of the 20th century made it possible for the first time to study the structures of the plasma tail of comets in detail. As with some other comets, variable structures could also be observed with Comet Daniel. By comparing his images of the comet at the Yerkes Observatory with time-shifted images at other observatories, Edward Barnard was also able to gain insights into the dynamic development of the dust tail.

The light of the comet was intensively examined spectroscopically , u. a. by Hans Rosenberg in Göttingen . The spectrograms showed comet-typical emission lines , u. a. of C 2 and CN. On August 10, Vesto Slipher was able to observe the carbon lines and the continuum as well as sodium D-lines at the Lowell Observatory . Their intensity was so strong that it was suspected that they had occurred two or three days earlier.

Several researchers, including Henri-Alexandre Deslandres and A. Bernard at the Paris Observatory , also obtained clear images of the spectrum of the comet's tail for the first time in August. They could see three previously unobserved bands in the violet and blue color range, which John Evershed had also observed at the Kodaikanal Observatory . It was only two years later that Alfred Fowler was able to identify these spectral lines as emissions of simply ionized carbon monoxide (CO + ).

Orbit

For the comet, an elongated elliptical orbit could be determined from 143 observation data over a period of about a year by Marsden , which is inclined by about 9 ° to the ecliptic . The comet's orbit is roughly on the same plane as that of the planets. At the point of the orbit closest to the sun ( perihelion ), which the comet passed on September 4, 1907, it was located at a distance of about 76.6 million km from the sun in the area between the orbits of Mercury and Venus . Previously, he was already on July 21 in about 166.3 million km distance on Mars passed, on August 2, he had about 0.76 AE / 113,300,000 km, the closest approach to the Earth reached and on 15 August it passed Mercury at a distance of about 59.5 million km. On September 24th, the comet passed Venus at a distance of about 85.3 million km.

The comet moves in an extremely elongated elliptical orbit around the sun. According to the orbital elements , which are afflicted with a certain uncertainty, its orbit before its passage through the inner solar system in 1907 still had an eccentricity of about 0.9986 and a semi-major axis of about 377 AU, so that its orbital period was about 7330 years. Due to the gravitational pull of the planets, in particular due to the relatively close passages of Uranus on August 13, 1902 and Saturn on February 1, 1904 at a distance of approximately 6 ⅔ AU, and at Jupiter on October 1, 1907 at approximately 4 ½ AU distance however, its orbital eccentricity was reduced to around 0.9983 and its semi-major axis to around 301 AU, so that its orbital period was shortened to around 5220 years. When it reaches the point of its orbit furthest from the sun ( aphelion ) around the year 4520 , it will be about 90 billion km from the sun, over 600 times as far as the earth and 20 times as far as Neptune . Its orbit speed in aphelion is only about 0.06 km / s. The comet's next perihelion passage may occur around the year 7130.

See also

Web links

Individual evidence

  1. ^ A b E. E. Barnard: Photographic Observations of Daniel's Comet. In: Proceedings of the American Philosophical Society. Vol. XLIX, No. 194, 1910, pp. 3–16 PDF; 3.63 MB (with many photos of the comet).
  2. ^ U. Baehr: The orbit of the comet 1907 IV (Daniel). In: Astronomical News. Vol. 249, 13-14, 1933, pp. 221-242 doi: 10.1002 / asna.19332491302 .
  3. ^ DH Levy: David Levy's Guide to Observing and Discovering Comets . Cambridge University Press, Cambridge 2003, ISBN 0-521-52051-7 , p. 44.
  4. ↑ JC Brandt: Observations and Dynamics of Plasma Tails. In: LL Wilkening, MS Matthews (Ed.): Comets. The University of Arizona Press, Tucson 1982, ISBN 0-8165-0769-4 , p. 512.
  5. ↑ H. Rosenberg: Comment on the spectrum of the comet 1907 d. In: Astronomical News. Vol. 175, 1907, pp. 401/402, bibcode : 1907AN .... 175..401R .
  6. ↑ MK Vainu Bappu, KR Sivaraman: Some characteristics of the solar wind inferred from the study of sodium emission from cometary nuclei. In: Solar Physics. Vol. 10, Issue 2, 1969, pp. 496-501 (with reference to Lowell Obs. Bull. No. 52, 1911), bibcode : 1969SoPh ... 10..496B .
  7. ^ J. Evershed: The spectrum of comet 1907 d (Daniel). In: Monthly Notices of Royal Astronomical Society. Vol. 68, No. 1, 1907, pp. 16-18 PDF; 98 kB .
  8. ^ D. Leverington: Babylon to Voyager and Beyond: A History of Planetary Astronomy . Cambridge University Press, Cambridge 2003, ISBN 978-0-521-80840-8 , pp. 341-342.
  9. ↑ C / 1907 L2 (Daniel) in the Small-Body Database of the Jet Propulsion Laboratory (English).Template: JPL Small-Body Database Browser / Maintenance / Alt
  10. ^ BG Marsden, Z. Sekanina, E. Everhart: New Osculating Orbits for 110 Comets and Analysis of Original Orbits for 200 Comets. In: The Astronomical Journal. Vol. 83, no. 1, 1978, pp. 64-71 doi: 10.1086 / 112177 .
  11. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .