Hale Bopp: Comet of the Century!

Jets and shells: 1996


Garradd Sep-23
Gordon Garradd
Sept. 23, 1996

ESO 20-3-96
Patricio Diaz Pazos.
La Silla
March 20, 1996


ESO
Nov. 2, 1996

jets
ESO
Aug. 27, 1996

ESO Aug-18
ESO
Aug. 18, 1996

False color images show up to seven jets emanating from the nucleus. The strongest can be traced to a distance of no less than 30,000 kilometres.

The first image was taken by Gordon Garradd with a HI-SIS22 camera and a Newton telescope (25cm at f4.1). Exposure time: 5 minutes. Field of view: 9 arcminutes. North is down.

The rest were taken at la Silla (Chile). The first of them (black & white) was taken with the NTT 3,5 m telescope, and only the nucleus can be seen. The last two were taken with the ESO Danish 1.54 m telescope. (original caption). The image taken on November 2, 1996, was obtained through a red filter and processed with a Laplace filter to enhance dust jets. The field is a little less than 3 arcminutes across. If one compares this image with those taken in August, 1996, it is evident that relative intensity varies. However, the position angles remain almost constant. Particulary nice examples are the jets at PA= 13, 185, 267, 267 i 300 degrees.

Spectral observations in the infrared region gave an estimated temperature of about -70º C for the dust emitted. This dust contains crystalline olivine. During November 1996, the silicates rich comet's central condensation reached 255 K degrees (-18 C degrees), or about 85 degrees over the equilibrium temperature for an inactive body at the same distance to the Sun.

The OH-production was about 30 times higher than that of comet Halley at the same heliocentric distance.

(From Comet Hale-Bopp Updates published on the ESO Web, by Richard M. West).


Hubble Images of Comet Hale-Bopp


Hal Weaver

The image shows the temporal evolution of Comet Hale-Bopp over the course of about 1 year, as observed by the Hubble Space Telescope. In the far-left frame we caught the comet about 60 hours after a huge outburst of dust. The middle frame shows the comet during a more quiescent phase in which hardly any structure is seen in the coma. The image at the far-right shows at least five jets sprouting from the nucleus. The nucleus of the comet is located at the center of each frame, but most of the light observed is due to scattered sunlight from fine dust grains that are emitted from the nucleus and which produce the cometary "coma".

Each frame above is 10 arcsec across. For the far-left frame this corresponds to 47,000 km at the comet, for the middle frame this corresponds to 49,000 km at the comet, and for the far-right frame this correponds to 21,000 km at the comet. (The comet was much closer to the Earth during the September 1996 observations.)


Images

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