Monday, May 23, 2011

New Comet: C/2011 J3 (LINEAR)

IAUC nr.9209, issued on 2011, May 20, announced the discovery of a new comet (discovery magnitude 19.7) by the LINEAR survey through their 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, May 14.3 The new comet has been designated C/2011 J3 (LINEAR).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEOCP, on 2011 May 18.4 remotely from the Tzec Maun Observatory.

Stacking of 34 unfiltered exposures, 60-sec each, obtained remotely on 2011, May 18.4 from the Tzec Maun Observatory (near Mayhill, NM) through a 0.4-m, f/9 reflector + CCD, shows that this object is a comet: very diffuse coma nearly 12 arcsec in diameter, with an extremely uncertain central condensation, that hampers a precise astrometric measurement.


Our confirming image (click for a bigger version):



MPEC 2011-K11 assignes the following preliminary orbital elements to comet C/2011 F1: T = 2011 Jan. 21.20; e= 0.88; Peri. = 24.81; q = 1.40 AU; Incl. = 114.81


According to COCD webpage, this is the 204th comet discovery for LINEAR Survey.

by Giovanni Sostero & Ernesto Guido

Thursday, May 12, 2011

New Comet: C/2011 J2 (LINEAR)

CBET nr.2714, issued on 2011, May 07, announced the discovery of a new comet (discovery magnitude 19.7) by the LINEAR survey through their 1.0-m f/2.15 reflector + CCD, on images obtained on 2011, May 04.2 The new comet has been designated C/2011 J2 (LINEAR).

After posting on the Minor Planet Center's 'NEOCP' webpage, this object has been found by several CCD astrometrists to show cometary appearance. We performed some follow-up measurements of this object while it was still listed in the NEO-CP, on 2011 May 05.5 and on May 06.5 remotely from the Tzec Maun Observatory.

After stacking nine unfiltered exposures, 300-sec each, obtained remotely on 2011, May 5.5 from the Tzec Maun Observatory (near Moorook, Australia) through a 0.15-m, f/7.3 refractor + CCD, we suspected the cometary nature of this object, since it appeared "soft". On a second, confirmatory, observing session (stacking of twenty-three unfiltered exposures, 300-sec each, obtained through the same instrumentation on 2011, May 06.5) we might confirmed our suspect of a tiny coma, since the FWHM of this object was measured about 40% wider than that of nearby field stars of similar brightness.


Our confirming image (click for a bigger version):




MPEC 2011-J31 assignes the following preliminary parabolic orbital elements to comet C/2011 F1: T = 2013 Dec. 23.18; Peri. = 85.62; q = 3.42 AU; Incl. = 122.69


According to COCD webpage, this is the 203th comet discovery for LINEAR Survey.

by Giovanni Sostero & Ernesto Guido

Wednesday, May 11, 2011

Bright Sungrazing Comet on May 10-11, 2011

A new bright comet diving into the Sun has been discovered on May. 09 by amateur astronomer Sergey Shurpakov using the images taken by SOHO spacecraft. This object belong to the famous Kreutz-group, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach.


C3 Image - May 10, 2011 (click to see a bigger version)



(Credit : SOHO)


Yesterday's now-evaporated bright Kreutz comet didn't die alone! This small companion was visible by its side on this C2 image:




C2 Movie - May 11 ,2011 (click to see a bigger version)



(Credit : SOHO)

This Kreutz probably peaked near mag 2. (It was just starting to saturate in the LASCO cameras)

You can read more details about 2010 bright SOHO comets here:

http://remanzacco.blogspot.com/2010/11/bright-sungrazing-comet-on-november-17.html
http://remanzacco.blogspot.com/2010/11/bright-sungrazing-comet-on-1314.html
http://remanzacco.blogspot.com/2010/10/new-bright-sungrazing-comet.html
http://remanzacco.blogspot.com/2010/04/new-bright-sungrazing-comet.html
http://remanzacco.blogspot.com/2010/01/bright-sungrazing-comet.html
http://remanzacco.blogspot.com/2010/01/new-sungrazing-comet.html
http://remanzacco.blogspot.com/2010/03/new-sungrazing-comet.html


by Ernesto Guido

Tuesday, May 10, 2011

New Comet: C/2011 H1 (Lemmon)

IAUC nr.9206, issued on 2011, May 05, announced the discovery of an apparently asteroidal object (discovery magnitude 19.7) by Alex R. Gibbs on CCD images taken on April 26.3 with the Mt. Lemmon 1.5-m reflector. Gibbs suspected that this object might show slight cometary appearance.

We performed some follow-up measurements of this object while it was still listed in the NEO-CP. Stacking of 8 unfiltered exposures, 300-sec each, obtained remotely on 2011, April 27.5 from the Tzec Maun Observatory (near Moorook, Australia) through a 0.15-m, f/7.3 refractor + CCD, shows that this object is slightly diffused: its FWHM is nearly twice compared to that of nearby field stars of similar brightness.

Initially the object was given the minor-planet designation 2011 GK_71 on MPEC 2011-H41 based on a series of one-night astrometry (Apr. 14) from Spacewatch (that shows little or no cometary appearance). Other observations obtained with the Steward Observatory Bok 2.3-m f/3 reflector (+ 90Prime CCD camera) during Apr. 29.256- 29.301 in 1".3 seeing, shows the object appears nearly stellar, but with a coma diameter of 5" and a tail 9" long in p.a. 111 deg.

The new comet has been designated C/2011 H1 (Lemmon).


Our confirming image (click for a bigger version):





MPEC 2011-J24 assignes the following preliminary parabolic orbital elements to comet C/2011 H1: T = 2006 Jan. 31.13; Peri. = 100.93; q = 6.91 AU; Incl. = 73.98; Node = 35.58


According to COCD webpage, this is the 36th comet for the Mt. Lemmon Survey.

UPDATE - May 22, 2011

According to IAUC 9209, the name associated with C/2011 H1 on IAUC 9206 is being abandoned, due to the belated identification of this comet:

COMET C/2002 VQ_94 = C/2011 H1 (LINEAR)

by Giovanni Sostero & Ernesto Guido

Monday, May 9, 2011