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Comet on April 16, 1996

March 16 ST6 CCD Image taken with Pine Mountain Observatory 32-inch telescope. Note the stars shining through the diffuse Coma.

Comets are basically frozen balls of ice and dust of approximate diameter 10 km. As they get near the sun and are heated, the cometary material is vaporized and thus releasing the entrapped dust and gas. Often times there are rapid changes in the appearance of the comet nucleus and coma as streams of dust and gas come off the nucleus. This can result in an asymmetric appearance as shown in the this most recent image taken at the NTT at ESO . Gas streaming off the comet nucleus forms the ion tail of the comet which points directly away from the sun due to interaction with the solar wind. This can be seen here in this recent image taken at La Silla with the 1-m telescope.

A cometary spectrum, shown below, generally reveals highly ionized emission lines of various C, CH and CN molecules which previously were stored in frozen form. Indeed, bombardment of the early earth by this material may have delivered many of the volatiles important to initiate chemical reactions in the early earth that synthesized amino acids. Hence, comets may really be your best friend and may have been the source of most of the earth's water.

Other Hyakutake Home Pages

Astronomical Headlines of the IAU Central Bureau for Astronomical Telegrams

Jet Propulsion Laboratory (JPL)

Instituto de Astrofisica de Canarias

Laboratorio Nacional de Astrofisica (Brazil)

University of Melbourne (Australia)

Crni Vrh Observatory (Slovenia)

University of Hawaii (D. Jewitt - submm work)

Vereinigung der Sternfreunde (VdS). In English and German.

Sky & Telescope (with charts showing the comet's motion in the sky in March and April 1996).

Astronomy Magazine (with charts).

This comet will pass within 10 million miles of the earth at its closest which will cause some to claim this a near-miss or even some predictions that it will hit the earth. Well, we will know in a week. The orbit is highly inclined with respect to plane of the solar system as shown below:

The manifestation of this high inclination is the rapid movement in the sky of the comet from south to North. On March 25 the comet will be at its point of closest approach. Although cometary brightnesses are notoriously difficult to accurately predict, this one is being well-studied and is evolving fairly rapidly. It is estimated to reach an integrated magntiude of +1 by March 25. This is as bright as the brightest appearing stars in the sky. However, the comet is not point like but is well-resolved and hence this brightness is spread out over some area. As such, the comet is best viewed from a dark location. The full extent of the Coma (the region of ionized gas around the nucleus) will likely be 1--2 degrees. The dust tail, illuminated via reflected sunlight, will be 15--25 degrees but rather diffuse.

The path of the comet through the sky is shown here. On March 24 the comet will be relatively close to the bright red star Arcturus. It should not be difficult to see.

The empheremis or positional data is shown here: Note the very rapid movement of the comet, almost 10 degrees per day. This makes telescopic observations really, really difficult!

 Date (UT)  Hr   R.A. J2000  Dec.   
 
1996 Mar 21 00  14 52 14.69 +05 06 41.3  
1996 Mar 21 02  14 52 07.77 +05 38 40.4   
1996 Mar 21 04  14 52 00.63 +06 11 29.8  
1996 Mar 21 06  14 51 53.24 +06 45 11.0  
1996 Mar 21 08  14 51 45.61 +07 19 45.9  
1996 Mar 21 10  14 51 37.71 +07 55 15.9  
1996 Mar 21 12  14 51 29.55 +08 31 43.0  
1996 Mar 21 14  14 51 21.10 +09 09 08.9 
1996 Mar 21 16  14 51 12.35 +09 47 35.5  
1996 Mar 21 18  14 51 03.30 +10 27 04.5 
1996 Mar 21 20  14 50 53.92 +11 07 38.0  
1996 Mar 21 22  14 50 44.21 +11 49 17.9 
1996 Mar 22 00  14 50 34.14 +12 32 06.2  
1996 Mar 22 02  14 50 23.70 +13 16 04.8 
1996 Mar 22 04  14 50 12.86 +14 01 15.8  
1996 Mar 22 06  14 50 01.62 +14 47 41.2 
1996 Mar 22 08  14 49 49.95 +15 35 23.0  
1996 Mar 22 10  14 49 37.83 +16 24 23.3 
1996 Mar 22 12  14 49 25.23 +17 14 44.1  
1996 Mar 22 14  14 49 12.13 +18 06 27.4 
1996 Mar 22 16  14 48 58.51 +18 59 35.1  
1996 Mar 22 18  14 48 44.32 +19 54 09.1 
1996 Mar 22 20  14 48 29.54 +20 50 11.1  
1996 Mar 22 22  14 48 14.13 +21 47 43.1 
1996 Mar 23 00  14 47 58.06 +22 46 46.5  
1996 Mar 23 02  14 47 41.29 +23 47 22.8  
1996 Mar 23 04  14 47 23.77 +24 49 33.4  
1996 Mar 23 06  14 47 05.46 +25 53 19.5  
1996 Mar 23 08  14 46 46.30 +26 58 41.9  
1996 Mar 23 10  14 46 26.23 +28 05 41.4  
1996 Mar 23 12  14 46 05.21 +29 14 18.5  
1996 Mar 23 14  14 45 43.15 +30 24 33.3  
1996 Mar 23 16  14 45 19.98 +31 36 25.6  
1996 Mar 23 18  14 44 55.63 +32 49 54.9 
1996 Mar 23 20  14 44 30.00 +34 05 00.4  
1996 Mar 23 22  14 44 02.99 +35 21 40.7  
1996 Mar 24 00  14 43 34.50 +36 39 54.1  
1996 Mar 24 02  14 43 04.40 +37 59 38.3  
1996 Mar 24 04  14 42 32.56 +39 20 50.6  
1996 Mar 24 06  14 41 58.84 +40 43 27.9  
1996 Mar 24 08  14 41 23.05 +42 07 26.5 
1996 Mar 24 10  14 40 45.01 +43 32 41.9 
1996 Mar 24 12  14 40 04.51 +44 59 09.6 
1996 Mar 24 14  14 39 21.31 +46 26 44.3 
1996 Mar 24 16  14 38 35.13 +47 55 20.0 
1996 Mar 24 18  14 37 45.67 +49 24 50.5 
1996 Mar 24 20  14 36 52.56 +50 55 09.2 
1996 Mar 24 22  14 35 55.39 +52 26 08.8  
1996 Mar 25 00  14 34 53.70 +53 57 41.8  
1996 Mar 25 02  14 33 46.93 +55 29 40.3  
1996 Mar 25 04  14 32 34.44 +57 01 56.1 
1996 Mar 25 06  14 31 15.47 +58 34 21.0 
1996 Mar 25 08  14 29 49.12 +60 06 46.3 
1996 Mar 25 10  14 28 14.34 +61 39 03.4 
1996 Mar 25 12  14 26 29.84 +63 11 03.7 
1996 Mar 25 14  14 24 34.05 +64 42 38.2 
1996 Mar 25 16  14 22 25.10 +66 13 38.4 
1996 Mar 25 18  14 20 00.62 +67 43 55.6 
1996 Mar 25 20  14 17 17.69 +69 13 21.0 
1996 Mar 25 22  14 14 12.60 +70 41 46.1 
1996 Mar 26 00  14 10 40.59 +72 09 02.1 
1996 Mar 26 02  14 06 35.47 +73 35 00.0   
1996 Mar 26 04  14 01 49.04 +74 59 30.3  
1996 Mar 26 06  13 56 10.25 +76 22 22.5   
1996 Mar 26 08  13 49 23.86 +77 43 24.8   
1996 Mar 26 10  13 41 08.40 +79 02 22.6  
1996 Mar 26 12  13 30 52.83 +80 18 56.8   
1996 Mar 26 14  13 17 51.14 +81 32 40.9  
1996 Mar 26 16  13 00 53.49 +82 42 55.3  
1996 Mar 26 18  12 38 12.31 +83 48 36.9  
1996 Mar 26 20  12 07 04.52 +84 48 01.0  
1996 Mar 26 22  11 23 46.77 +85 38 11.1  
1996 Mar 27 00  10 24 56.84 +86 14 28.5  
1996 Mar 27 02  09 12 26.42 +86 31 15.2  
1996 Mar 27 04  07 57 54.11 +86 25 31.3 
1996 Mar 27 06  06 54 50.42 +86 00 16.4 
1996 Mar 27 08  06 07 37.09 +85 21 55.5  
1996 Mar 27 10  05 33 37.48 +84 36 03.1  
1996 Mar 27 12  05 08 59.18 +83 46 12.9  
1996 Mar 27 14  04 50 41.90 +82 54 29.0  
1996 Mar 27 16  04 36 44.95 +82 02 02.9  
1996 Mar 27 18  04 25 49.99 +81 09 36.7  
1996 Mar 27 20  04 17 05.67 +80 17 36.0  
1996 Mar 27 22  04 09 57.59 +79 26 16.7  
1996 Mar 28 00  04 04 02.11 +78 35 48.7  
1996 Mar 28 02  03 59 02.57 +77 46 18.4  
1996 Mar 28 04  03 54 46.95 +76 57 49.6  
1996 Mar 28 06  03 51 06.37 +76 10 24.7  
1996 Mar 28 08  03 47 54.19 +75 24 04.8  
1996 Mar 28 10  03 45 05.29 +74 38 50.2  
1996 Mar 28 12  03 42 35.73 +73 54 40.7  
1996 Mar 28 14  03 40 22.38 +73 11 35.9  
1996 Mar 28 16  03 38 22.76 +72 29 34.9  
1996 Mar 28 18  03 36 34.86 +71 48 36.5  
1996 Mar 28 20  03 34 57.04 +71 08 39.6 
1996 Mar 28 22  03 33 27.95 +70 29 42.9  
1996 Mar 29 00  03 32 06.47 +69 51 44.8 
1996 Mar 29 02  03 30 51.67 +69 14 44.1  
1996 Mar 29 04  03 29 42.75 +68 38 39.2  
1996 Mar 29 06  03 28 39.05 +68 03 28.7  
1996 Mar 29 08  03 27 39.99 +67 29 11.0  
1996 Mar 29 10  03 26 45.07 +66 55 44.6  
1996 Mar 29 12  03 25 53.87 +66 23 08.2  
1996 Mar 29 14  03 25 06.02 +65 51 20.2 
1996 Mar 29 16  03 24 21.20 +65 20 19.2  
1996 Mar 29 18  03 23 39.13 +64 50 03.9  
1996 Mar 29 20  03 22 59.55 +64 20 32.8  
1996 Mar 29 22  03 22 22.25 +63 51 44.7  

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