New Comet: C/2012 K5 (LINEAR)

Cbet nr. 3127, issued on 2012, May 28, announces the discovery of a new comet (discovery magnitude 18.5) by the LINEAR survey on CCD images taken with the 1.0-m f/2.15 reflector on May 25.3. The new comet has been designated C/2012 K5 (LINEAR).

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 8 R-filtered exposures, 120-sec each, obtained remotely, from the ITelescope network (near Mayhill, NM) on 2012, May 27.4, with a 0.43-m f/6.8 astrograph + CCD,shows that this object is a comet coma 10" in diameter and a tail nearly 20" long in PA 210 deg.

Our confirmation image (click on the image for a bigger version):

M.P.E.C. 2012-K69 assigns the following preliminary parabolic orbital elements to comet C/2012 K5: T 2012 Nov. 29.04; e= 1.0; Peri. = 138.80; q = 1.15 AU; Incl.= 92.84

by Ernesto Guido, Giovanni Sostero & Nick Howes

2012 KT42 - Close Approach

Tomorrow, May 29, 2012 at about 07:07 UT, the asteroid designated 2012 KT42 will pass only ~14,000 km (8,700 miles) or about ~0.05 lunar distance (or 0.0001379 AU) above the Earth's surface. The asteroid was discovered by A. R. Gibbs in the course of Mt. Lemmon Survey with a 1.5-m reflector + CCD on May 28, 2012 at magnitude ~18.1.

Discovery images of asteroid 2012 KT42. Credit: Catalina Sky Survey/Mt. Lemmon Observatory

According to its absolute magnitude (H=28.8) this asteroid has an estimated size of roughly 3-10 meters, so it is a small object. We have been able to follow-up this object soon after his discovery while it was still on the neocp, from the Siding Spring-Faulkes Telescope South on 2012, May 28.4, through a 2.0-m f/10.0 Ritchey-Chretien + CCD.

At the moment of our images from FTS, "2012 KT42" was moving at about ~3.63 "/min and its magnitude was ~17.5. At the moment of its close approach around 07UT of tomorrow, 2012 KT42 will be bright as magnitude ~12.0 and moving at ~11021"/min.

Below you can see an image (stack of 5x5-second exposures) showing the asteroid. Click on the thumbnail to see a bigger version:

Below you can see an animation showing the motion of 2012 KT42. Each frame is a 5-second exposure through the FTS 2.0-m telescope. Click on the thumbnail to see a bigger version:

While there is no cause for concern, this is one of the closest approaches recorded. The table below shows the top 20 closest approaches by NEOs (Near-Earth Objects) sorted by nominal distance. The table has been computed on the NASA/Neo-JPL website. 2012 KT42 is the sixth closer approach to date. (2011 CQ1 is the closest non-impacting object in the asteroid catalog to date. The event that took 2008 TC3 into the earth's atmosphere is not included). Click on the thumbnail to see a bigger version:

On mpml mailing list, Andrew Lowe pointed out that on May 29 at about 10:10 UT,  2012 KT42 the minimum geocentric elongation from the center of the sun will be 0.1 degrees, so given the parallax there will be a transit across the sun. But with a diameter of about 5m, the object could be only about 0.07" across against the solar disk. Aldo Vitagliano provided this map of the transit (computed by his software Solex). Click on the thumbnail to see a bigger version:

According to calculation made by P. Tricarico, 2012 KT42 has experienced a partial eclipse while approaching Earth on May 28, 2012 between 14:05 UTC and 21:45 UTC, before the flyby. See animation below (click on it for a bigger version). Probably the first case ever of an approaching asteroid experiencing an eclipse and a transit during the same flyby with Earth. More info about this on Tricarico's website.

UPDATE - July 09, 2012

 "2012 KT42" was tracked by the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii as it whizzed inside the orbital distance of Earth geosynchronous satellites. Near-infrared spectral color measurements obtained simultaneously with the facility spectrograph (SpeX) while tracking the asteroid reveal a color signature interpreted as a carbon-rich composition (perhaps analogous to carbonaceous chondrite meteorites) from which a moderately dark reflectivity (albedo) is inferred. By knowing both the reflectivity and visible brightness of the object, the deduced size is about 7 meters.

The presented movie shows the NASA telescope first acquiring, then “locking on target” and tracking with the asteroid as it whizzes across the sky  — hence stars appear only as passing streaks. The movie is compiled from 2-second exposures obtained by the MORIS camera played back at 15 frames per second. (Thus the movie plays at about 30 times actual speed.) An internal reflection within the camera can be seen faintly to the left. Frequent up/down jumps of the image are normal telescope motions as part of the spectral data collection process.

by Ernesto Guido, Nick Howes & Giovanni Sostero

Recovery of comet P/2005 N3 (LARSON)

Cbet Circular No. 3123, issued on 2012, May 25, announces the recovery of comet P/2005 N3 (LARSON) =  2012 K4 (Larson) by our team; this comet was discovered on 2005, July 5.38 by S. Larson on CCD images taken in the course of the Mt. Lemmon Survey and it was last observed on 2005, December 02.

On 2012, May 22.6 we started an observing session to recover the periodic comet P/2005 N3. We found an object of magnitude ~20.4 located ~4 arcmin north-east of the nominal position. On May 25.6 we have been able to obtain a second night of observations.

Stacking of, respectively, seven and thirteen R-filtered exposures, 60-seconds each obtained remotely from the Haleakala-Faulkes Telescope North on 2012, May 22.6 and 25.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that comet P/2005 N3 (LARSON) has a ill-defined central condensation of R magnitude about 20.3, surrounded by a weak coma 5" in diameter, and a faint and broad tail, nearly 8" long toward the south-west.

                                  

Below you can find our recovery image of 2012, May 25.6 (click on the image for a bigger version)

The indicated correction to the prediction on MPC 75290 is Delta(T) = -0.26 day.  The linked orbital elements and an ephemeris by G. V. Williams appear on MPEC 2012-K54.

by Giovanni Sostero, Nick Howes & Ernesto Guido

New Comet: P/2012 K3 (GIBBS)

Cbet nr. 3122, issued on 2012, May 23, announces the discovery of a new comet (discovery magnitude 18.3) by  A. R. Gibbs on CCD images taken with the Mount Lemmon 1.5-m reflector on May 21.3. The new comet has been designated P/2012 K3 (GIBBS).

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of eight R-filtered exposures, 60-sec each, obtained remotely, from the Siding Spring-Faulkes Telescope South on 2012, May 23.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that this object is a comet: coma 5" in diameter and a tail nearly 5" long in PA 250 deg.

Our confirmation image (click on the image for a bigger version):

M.P.E.C. 2012-K50 assigns the following preliminary elliptical orbitalelements to comet P/2012 K3: T 2012 Sept. 3.56; e= 0.37; Peri. = 158.59; q = 2.16 AU; Incl.= 12.76

by Giovanni Sostero, Nick Howes & Ernesto Guido

Another Possible Nova in Oph

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Oph (TOCP Designation: J17395600-2447420) we performed some follow-up of this object remotely through the 0.43-m f/6.8 astrograph + CCD of ITelescope network (MPC Code - H06).

On our images taken on May 20.3, 2012 we can confirm the presence of an optical counterpart with unfiltered CCD magnitude 9.5 at coordinates:

R.A. = 17 39 57.00,  Decl.= -24 47 07.3

(equinox 2000.0; CMC-14 catalogue reference stars).

Below you can see  animation showing a comparison between our confirmation image and the archive POSS2/UKSTU plate (R Filter - 1996). Click on the thumbnail for a bigger version:

Our confirmation image. Click on it for a bigger version:

UPDATE - May 28, 2012

According to Cbet 3124, this variable has been designated NOVA OPHIUCHI 2012 No. 2. This nova was discovered by John Seach, Chatsworth Island, NSW, Australia, on six images (limiting mag 11.0) taken on May 19.484 UT with a digital SLR camera (+ 50-mm f/1.0 lens). Spectra obtained by different observers (T. Bohlsen, W. Vollmann, K. Imamura, F. M. Walter, C. Buil) suggests that the object is a classical nova.

Spectrum by K. Imamura (OUS)

by Ernesto Guido, Giovanni Sostero & Nick Howes

Update on comet C/2011 L4 (PANSTARRS)

Comet C/2011 L4 (PANSTARRS) was found by Pan-STARRS 1 telescope on Haleakala, Maui, on the night of 2011, June 5-6. At the moment of discovery the comet was at a distance of nearly 7.9 AU from the Sun (discovery magnitude 19.4). According to his orbit, around perihelion in March 2013 the comet would be located only 0.30 AU from the Sun and might become a bright naked eye object ( ~ magnitude 1). For more info about the discovery of this comet, see our previous post on this blog of 2011, June 09.

We performed some follow-up measurements of comet C/2011 L4 remotely from the Siding Spring-Faulkes Telescope South on 2012, May 18.5 through a 2.0-m f/10.0 Ritchey-Chretien + CCD. The comet is now at 4.6 AU from the Sun (m2 ~ 15.6).  Below you can see our follow-up image (click on it for a bigger version):

It's interesting to notice a very compact coma, this means active dust production even at 4.6 AU away from the Sun (very good news). The image processing shows an asymmetric coma, probably due to a line-of-sight effect. According to our previous experiences, the "jet-like" structures evidenced by the rotational-gradient  filtering, shows very likely the striking asymmetry of the coma/tail, instead of a genuìne activity due to the outgassing of the nucleus (that we are unlikely to resolve, at this time). This idea is confirmed by the appearance of the comet through the two other algorithms we applied, the azimuthal median subtraction and the 1/r theoretical coma subtraction. 

Anyway, our R-filtered image (that are showing mainly the dusty coma) shows that comet Panstarrs is pretty active, even at such big distances from the Sun (this is a good sign for future expectations on a bright comet, next year).

by Giovanni Sostero, Ernesto Guido & Nick Howes

First images of Comet 67P close to its aphelion

It's not often that amateurs can provide an important support to professional astronomers involved in an international space mission. At a recent comet conference for the forthcoming Rosetta mission, which will orbit comet 67P/Churyumov–Gerasimenko in 2014, and place a lander on the surface, Faulkes Telescope Pro-Am Programme Manager Nick Howes had put forward a detailed plan for long term observations of the comet 67P, using the twin Faulkes 2m telescopes based in Hawaii and Siding Spring. The proposal challenge was picked up by Faulkes Telescope user Richard Miles, who managed to image the comet on April 19th using Faulkes South (E10 mpc code), and by our Team using Faulkes North (F65 mpc code).

Stacking of 18 R-filtered exposures, 120-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2012, Apr.25.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, under good seeing conditions, shows that comet 67P has a stellar appearance, with R magnitude about 22 (limiting magnitude in our field of R about 22.5). At the moment of our image the comet was at roughly 5.683 AU from the Sun. 

Our image of comet 67P/Churyumov-Gerasimenko at the aphelion (click for a bigger version)

Before these observations using the Faulkes Telescopes, the comet 67P was last observed on July 2010. While our previous last observation of this comet dates back to 2010, March 08 when it was at 3.60 AU from the Sun.

To date, our observation of 2012, Apr. 25.5 is the farthest known observation of comet 67P taken by a ground-based observatory. According to "Periodic Comet Extreme Observations" by Jim Scotti, the previous farthest observation of comet 67P was by B. Mueller (mpc code 695 Kitt Peak) that imaged it on 1991 May 16.23 when the comet was at 4.98 AU from the Sun (click on the image below for a bigger version).  

Below you can see the residuals for the Faulkes (E10 + F65) obs calculated by the "Institute de Mécanique Céleste de Calcul des Ephémérides" using all the observations of comet 67P available in the archive (click on the image below for a bigger version).

These follow-up observations are important in several ways: they are helpful to refine comet's 67P orbital parameters, in the perspective of its future encounter with the "Rosetta" spaceprobe. Moreover, the data recently collected through the Faulkes telescopes, might also shed some light on the current activity of the comet's nucleus, that is approaching its aphelion (farthest distance from the Sun, well beyond the orbit of Jupiter).

by Nick Howes, Giovanni Sostero, Alison Tripp and Ernesto Guido