Wednesday, June 27, 2012

Possible Nova in Sgr - J17522579-2126215

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Sgr (TOCP Designation: J17522579-2126215) we performed some follow-up of this object remotely through the 0.10-m f/5 reflector + CCD of ITelescope network (MPC Code - H06). 

On our images taken on June 27.3, 2012 we can confirm the presence of an optical counterpart with R-filtered CCD magnitude 8.9 at coordinates:

R.A. = 17 52 25.79, Decl.= -21 26 21.6

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

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

An animation showing a comparison between our confirmation image and the archive POSS2/UKSTU plate (R Filter - 1996). Click on the thumbnail below:

UPDATE - July 08, 2012

According to Cbet 3156, this variable has been designated NOVA SAGITTARII 2012 No. 3. This nova was discovered by K. Itagaki (Yamagata, Japan) on an unfiltered CCD image taken on June 26.5494 UT with a 0.21-m reflector (mag 10.3). Spectra obtained by different observers (K. Imamura; H. Maehara; C. Buil; U. Munari) suggests that this nova is of theHe/N type, with hydrogen Balmer and He I in strong emission.

Spectrum by K. Imamura (OUS)

by Ernesto Guido, Giovanni Sostero & Nick Howes

Wednesday, June 13, 2012

Bright Near-Earth Asteroid 2012 LZ1

M.P.E.C. 2012-L30  issued on 2012, June 12 announces the discovery of a new Near-Earth object (discovery magnitude 15.1) by R. H. McNaught in the course of the Siding Spring Survey on CCD images taken with the 0.5-m Uppsala Schmidt. This new asteroid has been designated 2012 LZ1.

2012 LZ1 is a large Near-Earth Object (NEO) approximately 300-700 metres in size (H=19.7) and it has been classified as a PHA (Potentially Hazardous Asteroid). PHA are asteroids larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time. 

2012 LZ1 will be at its closest approach with Earth at ~14 lunar-distances (0.036 AU) on June 14, 23:10 UT.

We have been able to follow-up this object from the Haleakala-Faulkes Telescope North on 2012, June 13.5, through a 2.0-m f/10.0 Ritchey-Chretien + CCD.

At the moment of our images from FTN, "2012 LZ1" was moving at about ~33.64 "/min and its magnitude was ~14.2. At the moment of its close approach it will be bright as magnitude ~13.9 and moving at ~38.80 "/min. Anyway, for the following days, it will be bright enough to be imaged by most amateur telescopes. In fact it will drop below magnitude 17 on June 23.

Below you can see a 10-second exposure of  2012 LZ1 obtained with the FTN. The asteroid is slighlty trailed in the image due to its fast speed. Click on it for a bigger version.

Below you can see an animation showing the motion of 2012 LZ1. Each frame is a 10-second exposure through the FTN 2.0-m telescope. Click on the thumbnail to see a bigger version:

UPDATE - July 09, 2012

Using the planetary radar system at Arecibo Observatory, astronomers have determined that asteroid 2012 LZ1 is twice as large as originally estimated based on its brightness, and large enough to have serious global consequences if it were to hit the Earth. However, a new orbit solution also derived from the radar measurements shows that this object does not have any chance of hitting the Earth for at least the next 750 years. Scientists at Arecibo observed the asteroid on June 19, 2012, to measure its orbit more precisely and to determine its size, rotation rate, and shape, and found it to be about 1 kilometer (0.6 miles) in its largest dimension. The new size determination suggests that 2012 LZ1 must be quite dark, reflecting only 2-4% of the light that hits it.

by Nick Howes, Ernesto Guido & Giovanni Sostero

Friday, June 1, 2012

Recovery of comet P/1994 X1

Cbet Circular No. 3132, issued on 2012, May 31, announces the recovery of comet P/1994 X1 = 2012 K7 (McNaught-Russell) by our team; this comet was discovered on 1994, December 12 with the UK Schmidt Telescope at Siding Spring observatory and it was last observed on 1995, April 17.

On 2012, May 29 we started an observing session to recover the periodic comet P/1994 X1. We found an object of magnitude ~19.5 located ~35 arcsec south-west  of the nominal position, along the line of variations (LOV). Stacking of 7 R-filtered exposures, 60-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2012, May 29.6, through a 2.0-m f/10.0  Ritchey-Chretien + CCD, under good seeing conditions, shows that comet P/1994 X1 appears slightly diffuse, with a tiny coma about 3" in diameter, having a total m1 magnitude measured through a Bessel-R filter of about 19.5.

Second night follow-up observations, has been obtained on 2012, May 30.4, under the code H06. Stacking of 8 unfiltered exposures, 180-sec each, obtained on  2012, May 30.4 remotely from the ITelescope network near Mayhill, NM, through a 0.43-m f/6.8 astrograph + CCD + f/4.5 focal reducer, shows that this comet has a nearly stellar appearance.

Below you can find our recovery image of 2012, May 29.6 (click on the image for a bigger version)

Below you can find the recovery image of 2012, May 30.4 (click on the image for a bigger version)

While below you can see a small animation showing the movement of this faint comet on May 30.4 (click on the thumbnail to see the animation):

The indicated correction to the prediction on MPC 79019 is Delta(T) = +0.024 day. The linked orbital elements and an ephemeris by G. V. Williams appear on MPEC 2012-K75.

by Giovanni Sostero, Nick Howes, Erik Bryssinck & Ernesto Guido