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

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

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:

(Credit: SOHO; @SungrazerComets):

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

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

Padova - May 08, 2011 - Meeting Sezione Comete UAI & CARA Project

Photos from the Meeting of "Sezione Comete UAI" and "CARA Project" held in Padova, Italy on May 08, 2011:

http://bit.ly/iw1rTo

Specola di Padova

T PYXIDIS OUTBURST

CBET No. 2700 issued on April 15, 2011 reports that the recurrent nova T Pyxidis has been discovered in outburst. It was detected by by Mike Linnolt at visual magnitude 13.0 on 2011 April 14.2931 and the outburst has been visually confirmed by several observers.

This is the first outburst of T Pyx since December 7, 1966 (discovered then by Albert Jones), nearly 45 years ago, when it reached visual magnitude 6.5 from fainter than 15th magnitude; it was brighter than magnitude 8 for two months. Previous outbursts occurred in 1890, 1902, 1920, and 1944. There are only ten known galactic recurrent novae.

Below you can see the five maxima of the recurrent nova T Pyx from 1890 to 1967.

(Credit: AAVSO)

AAVSO Light-Curve for the period 1966 to present.

(Credit: AAVSO)

T Pyxidis is 6,000 light-years away in the dim southern constellation Pyxis, the Mariner's Compass. In September 1997, astronomers released an image of T Pyxidis taken using the Hubble Space Telescope. The Hubble's image shows that the shells of gas around the star that were blown off during several eruptions, are actually more than 2,000 gaseous blobs packed into an area that is 1 light-year across.

(Credits: Mike Shara, Bob Williams, and David Zurek (Space Telescope Science Institute); Roberto Gilmozzi (European Southern Observatory); Dina Prialnik (Tel Aviv University); and NASA)

T Pyx is located at the following coordinates:

RA 09h 04m 41.5s DEC -32 22' 47.4" (2000)


On April 15.41 we have been able to image T Pyx remotely through Gras network from Officer, Australia (MPC Code - E03) using a RCOS 12.5" - FL 1950 @ f/6.3. The object has reached the unfiltered magnitude ~8.5. Click on the image for a bigger version.

Below you can find an animation showing a comparison between our image and the archive DSS plate (R Filter - 1992) - Click on the thumbnail for a bigger version:

Below you can see a a spectrum of T Pyx in its rising phase reported by Arai-san at Koyama Astron. Obs. (Kyoto Sangyo U.) :

Follow-up observations are strongly encouraged!!

by Ernesto Guido & Giovanni Sostero

2011 GP59 - Close Approach

The Mpec circular 2011-G60 issued on April 09, 2011 announced the discovery of a new Aten asteroid officially designated 2011 GP59. This asteroid (~ magnitude 17.5) was discovered by La Sagra Survey through their 0.45-m f/2.8 reflector + CCD, on images obtained on April 08.9, 2011. After posting on the Minor Planet Center's 'NEOCP' webpage, other CCD astrometrists have been able to follow-up the new object to define its orbit.

According to the preliminay orbit, 2011 GP59 is an Aten type asteroid. This class of asteroids are defined by having semi-major axes of less than one astronomical unit (the distance from the Earth to the Sun). 2011 GP59 will have a close approach with Earth on April 15, 2011 at 1909 UTC at rougly 0.003567AU or 1.39 LD (Lunar Distance) reaching the magnitude ~13. Its absolute magnitude H=24.30 correspond to an approximate diameter of 50 meters.

2011 GP59 shows evident magnitude fluctuations. Below you can see a light-curve made by Brian Skiff (Lowell Observatory): 6-hours of observations using the Lowell 0.55-m Schmidt with 45-second exposures showing an amplitude in excess of 2 full magnitudes over a period of roughly 7.5 minutes.

(Credit: Brian Skiff - Lowell Observatory)

We have been able to follow 2011 GP59 on April 12.35 remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. Below you can see an animation showing the fast movement (the object was moving at 10.5 "/min) of 2011 GP59 on the sky on April 12, 2011. Each frame is a stack of 2x20-second exposure. The asteroid is moving from the top left corner to the bottom right corner. In the animation you can easily see the rapid brightness fluctuations of this object.

Click on the thumbnail below to see the animation:

UPDATE - April 14, 2011 - 13:30UT

We imaged 2011 GP59 on April 14.36, 2011 remotely from the GRAS Observatory (near Mayhill, NM) through a 0.51-m, f/6.9 reflector + CCD.

It's a single unfiltered exposure of 600 seconds, showing 2011 GP59 as trail with brightness fluctuations clearly evident (click on the image for a bigger version) :



by Ernesto Guido & Giovanni Sostero