New Comet: C/2013 B2 (CATALINA)

Cbet nr. 3390, issued on 2013, January 23, announces the discovery of a new comet (discovery magnitude 18.9) on images taken by J. A. Johnson with the Catalina Sky Survey's 0.68-m Schmidt telescope + CCD on January 16.2. The new comet has been designated C/2013 B2 (CATALINA). The apparently asteroidal object posted on the Minor Planet Center's NEOCP webpage, has been found to show cometary appearance by CCD astrometrists elsewhere.

We performed follow-up measurements of this object, while it was still on the neocp. Stacking of 22 R-filtered exposures, 50-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2013, Jan. 23.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that this object appears slightly diffuse compared to the nearby field stars of similar brightness and elongated toward PA 220.

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

M.P.E.C. 2013-B84 assigns the following preliminary parabolic orbital elements to comet C/2013 B2: T 2013 June 30.59; e= 1.0; Peri. = 156.14; q = 3.75;  Incl.= 43.56.

Images of  C/2013 B2 (CATALINA) taken in collaboration with the Faulkes Project and :

Shoeburyness High School - Philip Benson
South Hampstead High School - Chris Everall

by Nick Howes, Ernesto Guido & Alison Tripp

New Comet: P/2013 A2 (SCOTTI)

Cbet nr. 3376, issued on 2013, January 08, announces the discovery of a new comet (discovery magnitude 19.5) by J. Scotti with the 691 Steward Observatory, Kitt Peak, on images obtained with the 0.9-m f/3 reflector + CCD on January 06.2. The new comet has been designated P/2013 A2 (SCOTTI).

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 6 R-filtered exposures, 60-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2013, Jan. 08.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that this object appears "soft" compared to the nearby field stars of similar brightness and elongated toward PA 290. Our observations combined with those of Peter Phelps of Hazelmere School in the UK, using Faulkes South later in the day helped confirm the nature of the object.

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

M.P.E.C. 2013-A45 assigns the following preliminary elliptical orbital elements to comet P/2013 A2: T 2013 May  16.14; e= 0.57; Peri. = 182.74; q = 1.98 AU;  Incl.= 3.89.

Our confirmation image of comet P/2013 A2 (SCOTTI) was featured on BBC StarGazing Live on January 10, 2013. 

by Nick Howes & Ernesto Guido

Comets C/2012 K5 (LINEAR) & C/2012 F6 (Lemmon)

C/2012 K5 (LINEAR) & C/2012 F6 (Lemmon) are the brightest comets currently visible in the sky (together with comet C/2011 L4 PanSTARRS which is unobservable in Northern Hemisphere until 2013 March while is observable very low in the sky in the Southern Hemisphere until mid February).

C/2012 K5 (LINEAR) was discovered by the LINEAR survey on CCD images taken with the 1.0-m f/2.15 reflector on May 25.3. For more info about the discovery of this comet see our previous post here. Latest visual estimates indicate a total visual brightness of about m1 ~ 8.5. This comet is very close to the Earth now (~0.369 AU, while it is at ~1.3 AU from the Sun). The visibility condition is good in the Northern Hemisphere. But after mid January, the comet moves away from the earth and fade out rapidly. It will become observable in good condition also in the Southern Hemisphere after January.

Below you can see a graph generated using the software Orbitas and showing the C/2012 K5 predicted magnitude (in red) versus the maximum height (for Northern Hemisphere). Click on the image for a bigger version.

C/2012 K5 (LINEAR)  - Faulkes Telescope South - January 07, 2013 (North is up, East to the left)

C/2012 K5 (LINEAR)  MCM (Median Coma Model) 

The MCM filter creates an artificial coma, based on the photometry of the original image, and subtract the original image itself in order to highlight the internal zones of different brightness that are very close to the inner core and that would normally be hidden from the diffuse glow of the comet.

C/2012 K5 (LINEAR)  RWM (Radial Weighted Model) 

RWM - 1/r theoretical coma subtraction.

Below you can see an animation of comet C/2012 K5 obtained using the same frames of the images above. Click on the thumbnail for a bigger version:

C/2012 F6 (Lemmon) was discovered by the Mount Lemmon Survey on CCD images taken with the 1.5-m reflector on March 23, 2012. Latest visual estimates indicate a total visual brightness of about m1 ~ 8.0. This comet is getting brighter much faster than expected. Perihelion is on March 24 at 0.73AU in 2013 March. If this trend continues it may brighten up to magnitude ~3. In the Northern Hemisphere, it is only observable until early January and then after middle May 2013 while in the Southern Hemisphere, it keeps observable while brightening gradually after this in good condition.

Below you can see a graph generated using the software Orbitas and showing the C/2012 F6 predicted magnitude (in red) versus the maximum height (for Northern Hemisphere). Click on the image for a bigger version. (Please consider that as explained above, the comet is surprisingly bright and over 4 magnitudes brighter than the ephemeris)

 C/2012 F6 (Lemmon) - Faulkes Telescope South - January 07, 2013 (North is up, East to the left)

C/2012 F6 (Lemmon) -  MCM (Median Coma Model)  

C/2012 F6 (Lemmon) - RWM (Radial Weighted Model)

Below you can see an animation of comet C/2012 F6 obtained using the same frames of the images above. Click on the thumbnail for a bigger version:

Images of  C/2012 K5 & C/2012 F6 taken in collaboration with the Faulkes Project and :

Longley Park Sixth Form College  - Ismail Musa
Glenlola Collegiate   -  Jacquie Milligan
Bury College   -  Dr. Lyshia Quinn

by Ernesto Guido, Nick Howes & Martino Nicolini

New Comet: C/2012 Y3 (MCNAUGHT)

Cbet nr. 3367, issued on 2013, January 01, announces the discovery of a new comet (discovery magnitude 15.2) by the E12 Siding Spring Survey on images obtained with the 0.5-m Uppsala Schmidt + CCD on December 30.6. The new comet has been designated C/2012 Y3 (MCNAUGHT).

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 19 unfiltered exposures, 30-sec each,obtained remotely,from Q62 (iTelescope Observatory, Siding Spring) on 2013, Jan. 01.46, through a 0.32-m f/9.0 Ritchey-Chretien + CCD shows that this object is a comet: coma about 10" in diameter with a fan-shaped tail elongated in PA 85.

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

M.P.E.C. 2013-A03 assigns the following preliminary parabolic orbital elements to comet C/2012 Y3: T 2012 Aug. 26.59; e= 1.0; Peri. = 236.15; q = 1.78 AU; Incl.= 73.90.

by Ernesto Guido & Nick Howes