Astronomical Association San Costantino di Briatico, Calabria, Italy
Latest Elaboration of Stereo H1A (Nasa) Satellitecomet ISON images
Sum of all the fits original images
C/2012 S1 (ISON) is a sungrazing comet discovered on 21 September 2012 by Vitali Nevski (Виталий Невский, Vitebsk, Belarus) and Artyom Novichonok (Артём Новичонок, Kondopoga, Russia). The discovery was made using the 0.4-meter (16 in) reflector of the International Scientific Optical Network near Kislovodsk, Russia and the automated asteroid-discovery program CoLiTec. Precovery images by the Mount Lemmon Survey from 28 December 2011 and by Pan-STARRS from 28 January 2012 were quickly located. Follow-up observations were made on 22 September by a team from Remanzacco Observatory in Italy using the iTelescope network. The discovery was announced by the Minor Planet Center on 24 September. Observations by SWIFT suggest that the comet nucleus is around 5 kilometers (3.1 mi) in diameter. Recent observation made by HST put the dimension of the radius of the comet less than 2 km!
Epoch = 2013 Dec. 14.0 TT
T = 2013 Nov. 28.78555 TT Peri. = 345.56521
e = 1.0000013 Node = 295.65272 2000.0
q = 0.0124431 AU Incl. = 62.39824
From 163 observations 2011 Dec. 28-2012 Oct. 2, mean residual 0".4.
Central Bureau Electronic Telegrams, 3496, 1 (2013). Edited by Green, D. W. E.
Jian-Yang Li, Planetary Science Institute; H. A. Weaver, Applied Physics Laboratory, Johns Hopkins University; M. S. Kelley, T. L. Farnham, and M. F. A'Hearn, University of Maryland; M. M. Knight, Lowell Observatory; M. J. Mutchler, Space Telescope Science Institute; P. Lamy, Laboratoire d'Astrophysique de Marseille; and I. Toth, Hungarian Academy of Sciences, obtained broadband images of comet C/2012 S1 (cf. CBET 3238) on Apr. 10 (when at r = 4.15 AU and D = 4.24 AU) using the Hubble Space Telescope (HST) WFC3/UVIS cameras with the F606W and F438W filters. The observations were performed in three HST orbits, with the second orbit about 2.5 hr after the first, and the last about 13.5 hr from the second. Preliminary analysis using a coma-nucleus separation technique (cf. Lamy et al. 2009, A.Ap. 508, 1045) suggests a nuclear radius less than 2 km. The total brightness of the comet within a 0".24-diameter aperture remained unchanged within 0.03 mag over the 19-hr observing window. Broadband photometry yielded Af(rho) = 1376 cm at 589 nm, and 1281 cm at 433 nm, consistent with a red slope of 5 percent per 0.1 micron for the coma dust. A well-defined jet is visible after removing the 1/r brightness distribution. The jet is centered on position angle 290 deg, with a cone angle of 45 deg, a projected length of 1".6, and a slight curvature towards the north near the end. No temporal change in the morphology is observed over the three epochs, suggesting that the jet is circumpolar. Under this assumption, the jet's apparent position constrains the rotational pole to lie within 30 deg of R.A. = 330 deg, Decl. = 0 deg (equinox 2000.0). The images are posted at the following website URL: http://hubblesite.org/newscenter/archive/releases/2013/14/. Total-magnitude estimates (visual unless otherwise noted):2012 Oct. 14.77 UT, 17.3 (K. Yoshimoto, Yamaguchi, Japan, 0.16-m reflector + CCD); Dec. 19.82, 16.5 (Yoshimoto); 2013 Jan. 13.90, 14.8 (J. J. Gonzalez, Leon, Spain, 0.20-m reflector; visual); 21.85, 15.8 (S. Shurpakov, Baran', Belarus, 20-cm reflector + CCD); Feb. 2.90, 15.0 (U. Pilz, Leipzig, Germany, 32-cm reflector; visual); 11.57, 15.8 (Yoshimoto); 23.74, 15.8 (Shurpakov); Mar. 6.72, 15.5 (Shurpakov); 10.76, 16.1 (T. Scarmato, Calabria, Italy, 25-cm reflector + CCD + R_c filter); 23.79, 15.8 (Scarmato); Apr. 6.82, 16.2 (Scarmato); 9.48, 15.8 (Yoshimoto); 19.81, 16.2 (Scarmato).
CopyRighted CBAT (Central Bureau Electronic Telegram), 3496, 1 (2013). Edited by Green, D. W. E.
My first observation
Some consideration on this trends.
The recovery of the comet by Bruce is a good news and the magnitude measured is not that expected; first because the comet is at 2.5 A.U. from the Sun, so in the zone of the space where us we wait the sublimation of the ice with an increase of the activity and the brightness of the comet.
The comet seem instead to continue to bright slowly but this is true?
To me the question is more complex of that that appear. In my long time curve of light of the comet, I detected some “outburst” and in particular on images taken on images taken on FT Telescope on 2013 January 18 and 21, I have detected a strong increase of the Af(rho) value, the parameter that measure the Qdust production. Other minor “outburst” was been detected in March and April. (see graph at the left). The average value of the parameter, if the comet is in the normal “quite” state should be around 1300 cm in the period considered; the same beaviour was been observed for smaller aperture of the diameter of the coma of the comet; the question is: what happen in January? To answer this question I do some elaborations of Hubble Space Telescope of comet ISON taken on April and May 2013.
On 2013 April 10 and May 8 the Hubble Space Telescope images comet C/2012 S1 with some filter; the images are fantastic.
For the images taken on 2013 April 10 credited to Hubble Space Telescope Team and Prof. J. Yang-Li PI, and images taken on 2013 May 8, Hubble Space Telescope Team and Z. Levay PI.
Elaboration and Copyright T. Scarmato
Using a procedure to model the inner side of the coma of the comet, I was able to detected some interesting structure of the nucleus and the coma; looking at the left images we can to noticed two structure in two different positions; what at the center and close to the jet is the nucleus the other I don’t know! My suspicious is that is a fragment that is linked with the “strong event” happened in January; actually unfortunately I have not other images with the same resolution of HST, but I am working to verify that! I am waiting Spitzer images!
The strong event can to have caused a fragmentation and/or a loss of a big part of the surface of the comet and put the comet in a “anomalous quite state”.
News and update will be put in this page in the future.
Comet From The Space at the Perielion
Updated………………. 2013 November 15