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Unexpected Brightening of Comet 17P/Holmes

Unexpected Brightening of Comet 17P/Holmes

25 October 2007

Comet 17P/Holmes now makes for an unexpected sight in the night sky. In the night of 23 to 24 October the comet has brightened by an enormous factor of several hundred thousand, from a magnitude of about 17 to a magnitude of about 2.8!

Position of comet 17P/Holmes in Perseus, late October 2007

This means the comet can now be readily observed with the naked eye. Although it is bright, comet 17P/Holmes does not have a distinctive tail, rather it appears as a yellowish star with a fuzzy envelope in the constellation of Perseus.

As yet, it is not clear what caused the enormous brightening of comet 17P/Holmes, but possible causes are sudden outgassing or the release of particles from the comet's nucleus.

The comet's position on the sky for the next two weeks is detailed below. For a more extensive ephemeris of the comet's position see the "related links" in the right-hand side navigation.

Orbit

Discovered by Edwin Holmes in November 1892, comet 17P/Holmes is a periodic comet with an orbital period of 6.88 years. Its eccentric orbit takes the comet from 2.05 AU out to 5.02 AU from the Sun.

17P/Holmes orbital elements
Epoch 2007 Oct. 27.0 TT = JDT 2454400.5

Perihelion distance (AU) q

2.053218

Mean daily motion (°/day) n

0.1431946

Semimajor axis (AU) a

3.618414

Eccentricity e

0.432564

Period (y) P

6.88

Inclination (°) i

19.1126

Argument of Perihelion (°)

24.2712

Argument of Ascending Node (°)

326.8646

Source: Minor Planet Center

Five and a half months ago, in early May 2007, comet 17P/Holmes passed through its latest perihelion at 2.053 AU from the Sun, at which time it was 2.77 AU from the Earth. Since then its distance from the Sun has been increasing but the Earth has been catching up with the comet as the Earth orbits closer to the Sun.

Over the coming two weeks, Earth will continue to close-in on the comet. Early November the distance between the comet and Earth will be at its smallest: 1.62 AU.

Date Coordinates (J2000.0) Distance (AU)
R.A. (h m) Dec. (°) to Earth to Sun
25.10.2007 03 52.96 +50 08.2 1.635 2.440
26.10.2007 03 52.08 +50 12.6 1.632 2.444
27.10.2007 03 51.17 +50 16.6 1.630 2.447
28.10.2007 03 50.22 +50 20.4 1.628 2.451
29.10.2007 03 49.24 +50 23.8 1.627 2.455
30.10.2007 03 48.24 +50 26.8 1.625 2.459
31.10.2007 03 47.20 +50 29.6 1.624 2.463
01.11.2007 03 46.14 +50 31.9 1.623 2.467
02.11.2007 03 45.06 +50 33.9 1.622 2.471
03.11.2007 03 43.95 +50 35.6 1.621 2.475
04.11.2007 03 42.82 +50 36.8 1.621 2.478
05.11.2007 03 41.67 +50 37.8 1.620 2.482
06.11.2007 03 40.50 +50 38.3 1.620 2.486
07.11.2007 03 39.32 +50 38.5 1.620 2.490

Comet 17P/Holmes - coordinates and distances.
Source: Minor Planet Center

Last Update: 1 September 2019
28-Nov-2021 21:19 UT

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