* Astronomy

Blobrana · L

Comet 17P/Holmes

Blobrana · L

RE: Comet 17P/Holmes

Blobrana · L

In an attempt to understand these odd occurrences, astronomers pointed NASA's Spitzer Space Telescope at the comet in November 2007 and March 2008. By using Spitzer's infrared spectrograph instrument, Reach was able to gain valuable insights into the composition of Holmes' solid interior. Like a prism spreading visible-light into a rainbow, the spectrograph breaks up infrared light from the comet into its component parts, revealing the fingerprints of various chemicals.

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Blobrana · L

When comet Holmes unexpectedly erupted in 2007, professional and amateur astronomers around the world turned their telescopes toward the spectacular event. Their quest was to find out why the comet had suddenly exploded.
Observations taken of the comet after the explosion by NASA's Spitzer Space Telescope deepen the mystery, showing oddly behaving streamers in the shell of dust surrounding the nucleus of the comet. The data also offer a rare look at the material liberated from within the nucleus, and confirm previous findings from NASA's Stardust and Deep Impact missions.

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Blobrana · L

In October, fix your stares on the sky to watch the sporadic comet '17P/HOLMES'. Throughout October and November, it will be visible in the Northern Hemisphere. The comet is visible in India and is rightly regarded as 'morning comet'. The comet could be seen in Mysore at about 1:00 am to 4:50 am.

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Ephemeris


Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   mag    mag
2008 10 11    09 03.22   +26 28.6    4.149    3.882    67.7    13.8        20.8
2008 10 16    09 06.77   +26 15.1    4.096    3.900    71.7    14.0        20.8
2008 10 21    09 09.99   +26 03.0    4.040    3.917    75.9    14.3        20.8
2008 10 26    09 12.87   +25 52.3    3.982    3.935    80.1    14.4        20.8
2008 10 31    09 15.38   +25 43.2    3.923    3.953    84.5    14.5        20.8
2008 11 05    09 17.50   +25 35.8    3.863    3.970    88.9    14.5        20.7
2008 11 10    09 19.21   +25 30.1    3.803    3.987    93.5    14.4        20.7
2008 11 15    09 20.49   +25 26.2    3.743    4.005    98.1    14.2        20.7
2008 11 20    09 21.34   +25 24.0    3.684    4.022   102.9    13.9        20.6
2008 11 25    09 21.72   +25 23.8    3.626    4.039   107.8    13.5        20.6
2008 11 30    09 21.62   +25 25.2    3.570    4.056   112.8    13.0        20.6

Blobrana · L

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   m1 
2008 05 04    05 29.00   +35 43.9    3.939    3.251    41.4    11.8  20.7  
2008 05 09    05 37.16   +35 33.2    4.004    3.272    38.3    11.0  20.7  
2008 05 14    05 45.31   +35 22.0    4.066    3.293    35.3    10.2  20.8  
2008 05 19    05 53.45   +35 10.3    4.125    3.314    32.3     9.4  20.9  
2008 05 24    06 01.56   +34 57.8    4.180    3.335    29.4     8.6  21.0  
2008 05 29    06 09.63   +34 44.7    4.232    3.356    26.5     7.7  21.0

Blobrana · L

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   m1 
2008 03 05    03 55.92   +37 48.1    2.992    2.993    80.6    19.1  19.5
2008 03 10    04 02.97   +37 34.6    3.078    3.015    77.1    18.7  19.6
2008 03 15    04 10.21   +37 22.4    3.164    3.037    73.6    18.3  19.7
2008 03 20    04 17.63   +37 11.1    3.248    3.058    70.2    17.8  19.8
2008 03 25    04 25.19   +37 00.6    3.332    3.080    66.9    17.3  19.9
2008 03 30    04 32.89   +36 50.7    3.415    3.101    63.5    16.8  20.0

Blobrana · L

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase   m1 
2008 02 04    03 19.47   +39 48.4    2.480    2.863   102.7    19.6  18.8  
2008 02 09    03 24.68   +39 22.4    2.563    2.885    98.9    19.7  18.9  
2008 02 14    03 30.29   +38 59.1    2.648    2.907    95.1    19.8  19.1  
2008 02 19    03 36.26   +38 38.3    2.733    2.928    91.4    19.7  19.2  
2008 02 24    03 42.54   +38 19.7    2.819    2.950    87.7    19.6  19.3  
2008 02 29    03 49.11   +38 03.0    2.905    2.972    84.1    19.4  19.4

Blobrana · L

Comet 17P/Holmes

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Blobrana · L

Title: The comet 17P/Holmes 2007 outburst: the early motion of the outburst material
Authors: M. Montalto (1), A. Riffeser (2), U. Hopp (1 and 2), S. Wilke (2), G. Carraro (3) ((1) MPE, Munchen, Germany, (2) Universitats-Sternwarte Munchen, Germany, (3) ESO Santiago)

Context. On October 24, 2007 the periodic comet 17P/Holmes underwent an astonishing outburst that increased its apparent total brightness from magnitude V ~17 up to V ~2.5 in roughly two days. We report on Wendelstein 0.8 m telescope (WST) photometric observations of the early evolution stages of the outburst.
Aims. We studied the evolution of the structure morphology, its kinematic, and estimated the ejected dust mass.
Methods. We analysed 126 images in the BVRI photometric bands spread between 26/10/2007 and 20/11/2007. The bright comet core appeared well separated from that one of a quickly expanding dust cloud in all the data, and the bulk of the latter was contained in the field of view of our instrument. The ejected dust mass was derived on the base of differential photometry on background stars occulted by the moving cloud.
Results. The two cores were moving apart from each other at a relative projected constant velocity of (9.87 ± 0.07) arcsec/day (0.135 ±0.001 km/sec). In the inner regions of the dust cloud we observed a linear increase in size at a mean constant velocity of (14.6±0.3) arcsec/day (0.200±0.004 km/sec). Evidence of a radial velocity gradient in the expanding cloud was also found. Our estimate for the expanding coma's mass was of the order of 10^{-2}-1 comet's mass implying a significant disintegration event.
Conclusions. We interpreted our observations in the context of an explosive scenario which was more probably originated by some internal instability processes, rather than an impact with an asteroidal body. Due to the peculiar characteristics of this event, further observations and investigations are necessary in order to enlight the nature of the physical processes that determined it.

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