Monday, May 26, 2008

Possible Nova in Ophiucus

Following the posting on the Central Bureau's unconfirmed-objects webpage about a possible nova in Ophiucus, today we performed some follow-up of this object remotely through a 0.25-m, f/3.4 reflector + CCD, near Mayhill (NM).

We can confirm the presence of a relatively bright counterpart at coordinates:

R.A. = 17h39m50s.95, Decl. = -23o 50'00".9 (equinox 2000.0; UCAC-2 catalogue reference stars).

Our multicolor photometry provides the following values: 2008, May. 26.31, B= +11.42, V= +10.45, R= +9.81 (estimated accuracy +/- 0.05 magnitudes in each color).

Our image of this transient is available at the following Url:

http://tinyurl.com/64bw3x

Comparison with a UK Schmidt Telescope red plate, obtained on 1991, August 11 show nothing in this position (limiting magnitude near 20).

by E. Guido and G. Sostero (Remanzacco Observatory, Italy)

Sunday, May 25, 2008

Comet 7P/Pons-Winnecke

Prompted by a comment published on the newsgroup [Comets-ml] about a possible outburst of comet 7P/Pons-Winnecke detected by G. Muler, on 2008, May 23, we performed some follow-up of this object. Stacking of 30 unfiltered exposures, 60 seconds each, obtained remotely from Mayhill (NM) on 2008, May 25.2 through a 0.25-m, f/3.4 reflector + CCD, show that 7P/Pons-Winnecke currently has a diffuse coma nearly 25 arcsec in diameter, with a sharp central condensation.

Total magnitude m1 was measured to be R= 15.9. Preliminary afrho calculation provides a rather flat trend, with an average value of 30 +/- 5 cm.

Our image is available here:

http://tinyurl.com/62eyan

by Ernesto Guido and Giovanni Sostero

Monday, May 19, 2008

Comet 46P/Wirtanen

Prompted by a comment published on the newsgroup [Comets-ml] about a possible outburst of comet 46P/Wirtanen reported by M. Kidger and his spanish collaborators, we performed some follow-up of this object.

Stacking of 10 unfiltered expsoures, 50 seconds each, obtained remotely from Mayhill (NM) on 2008, May 18.2 through a 0.25-m, f/3.4 reflector + CCD, show that 46P/Wirtanen currently has a very compact coma nearly 15 arcsec in diameter. The total magnitude m1 was measured to be R= 14.8. Preliminary afrho calculation provides a rather flat photometric profile with a value ranging from 90 to 130-cm for apertures diameters passing from, respectively, 10,000 to 30,000-Km at the comet distance.

Our image is available here:
http://tinyurl.com/3vu75s

by Ernesto Guido and Giovanni Sostero

Friday, May 16, 2008

Comet C/2008 J6 (HILL)

IAU Circular nr.8945, issued on 2008, May 15, announces the discovery by R. E. Hill of a new comet, named C/2008 J6 (HILL).

It was found in the morning sky within Pegasus, with the 0.68-m schmidt of the "Catalina Sky Survey" on 2008, May 14.46, and it has been described by the discoverer as having a diffuse coma with a clear central condensation and a fan-shaped tail 1 arcmin long in p.a. 210 degrees.

After posting on the Minor Planet Center's 'NEOCP' webpage, several observers reported about its cometary nature (J. C. Pelle, N. Teamo, S. Nakano, Y. Ikari, J. E. McGaha and the undersigneds).

We observed it remotely from Mayhill (NM) on 2008 May 15.4, through the 0.25-m, f/3.4 reflector + CCD of the "Global Rent A Scope" network: we found a sharp central condensation about 8" in diameter, surrounded by a faint, extended coma about 25" in diameter (total mag about 15.5, nuclear magnitude about 16.6) and a fan-shaped tail 30" long toward the southwest.

Our image is available here:
http://tinyurl.com/5xtvkj

Preliminary orbital elements from the Minor Planet Center (http://tinyurl.com/5d9twg) assume that this object moves along a parabolic orbit (i= 46 deg, q= 2.1 AU); perihelion has been reached at the end of April 2008. According the current ephemerids, in the next future this comet will decrease its brightness.

by Ernesto Guido and Giovanni Sostero

Sunday, May 11, 2008

The Virtual Impactor Minor Planet 2008 HJ

After its posting on the NEO Confirmation Page with the NEO-Confirmation Page with code BK08329, follow-up was secured by a number of observers, among which our osservatory (M.P.C. Code #473).

Afterwards, M.P.E.C. 2008-H26 (http://tinyurl.com/4yg3d3), issued on 2008 April 25 , 20:51 U.T. , has announced the discovery of 2008 HJ: this is the tempoarary designation of the object, by the M.P.C. observatory code #704 Lincoln Laboratory ETS.

After few days, the asteroid has been catalogued as a "virtual impactor", because it has a very little probability that its orbit could be a threat for our planet; however currently it is flagged with a level "0" in the Torino scale. This situation could change, so these kind of minor planets are kept under strict monitoring by two istitutions , that are collecting the updated astrometric measurements about 2008 HJ : the Neo Object Program and Neo Dys Risk Page.

As suggested by the Minor Planet Center, it is mandatory to perform futher follow-up of this asteroid in next months, in order to improve the knowledge of its orbit with new measures. This is important to reduce the uncertains on orbital parameters and to confirm that 2008 HJ really belongs to the 0 class of Torino scale, that rappresents a very low level of hazard.

This image of 2008 HJ has been obtained by Remanzacco Observatory team in the same day of its discovery:

http://tinyurl.com/44y8bk

by Virgilio Gonano and Ernesto Guido

Thursday, May 8, 2008

Comet C/2008 J2 (BESHORE)

IAU Circular nr.8941, issued on 2008, May 7, announces the discovery by E. Beshore of a new comet named C/2008 J2 (BESHORE).

It was discovered with the 1.5-m reflector of the "Mount Lemmon Sky Survey" on 2008, May 6.44, and it has been described by the discoverer as having a bright condensed coma, diameter of 20 arcsec. Preliminary orbital elements from the Minor Planet Center show that this object moves along a parabolic orbit (i= 16.6 deg, q= 1.1 AU); perihelion is expected to occour on 2008 October 7th. According the current ephemerids, the new comet "Beshore" will reach approximately magnitude 8.5 at perihelion.

Soon after its posting in the M.P.C. NEO_Confirmation Page (around noon, April 6th) with the ID code "8JBD660", we wanted to get a close look at this relatively bright object, picked up just hours earlier. Unfortunately the weather conditions in our traditional observing site (Remanzacco Observatory, MPC code 473) were poor. So we decided to gave it a try from a new observatory (now under completion) that is operated by our astro club:

http://tinyurl.com/64takb (very large file!!!)

This new observing site is located about 20 Km East of Remanzacco, in the slopes of a nice mountain, named Mount Matajur. Since the Mount Matajur Observatory is 1340-m high, we hoped to skip at least some part of the haze that was affecting the plains were the Remanzacco observatory is located.

It was a wise decision, since while there, the sky suddently cleared up, so we were finally able to inaugurate our NEO/comets follow-up observing program from the recently "appointed" astrometric site MPC #B68!

When we located this relatively slow moving interloper in Ophiucus through a 0.2-m f/3 reflector + CCD, we initially considered it a star-like object (or at least, this was our very first impression looking at the single raw images that appeared on the PC monitor). However, when we carefully inspected the final stacking of 20 unfiltered exposures (60 seconds each) obtained on 2008, May 6.95, we immediately realized that this was not the case, since we noticed an extremely compact coma of almost uniform brightness about 20 arcsec in diameter, slightly elongated toward south-west:

http://tinyurl.com/68dzl6

The total magnitude m1 was measured to be R~14

Afterwards, we decided to continue the study of this comet candidate (still listed in the NEO-Confirmation Page as object "8JBD660") with the instruments of the "Rent A Scope" network. So, on 2008, May 7.3 we connected with a 0.25-m f/3.4 reflector + CCD located near Mayhill (NM), where we initially collected 10 unfiltered exposures, 60-seconds each, that we stacked. Analyzing the result, we were able to confirme the existence of a coma nearly 25 arcsec in diameter elongated toward PA 240 deg, with a very flat photometric profile:

http://tinyurl.com/6kbfh3

Filtered photometry performed soon afterwards (on 2008, May 7.37) through the same scope and a Cousins Red filter provided a total m1 magnitude of R~ 13.9, while a preliminary afrho calculation (proxy of the dust abundance within the coma) gave a value of nearly 450 +/- 80 cm; considering its current distance from the Sun, this seems to point toward an active comet.

by Giovanni Sostero and Ernesto Guido

Monday, May 5, 2008

Recovery of Periodic Comet 15P/Finlay

Periodic comet 15P/Finlay has been picked-up by the undersigneds on 2008, April 27.79 by means of a 0.25m, f/6 reflector + CCD (remotely, near Moorook, AU) and confirmed on 2008, April 28.70 through the same instrumentation.

Our astrometry:
0015P C2008 04 27.79053 22 58 27.09 -12 37 33.0 17.2 N EJ027D90
0015P C2008 04 27.79941 22 58 29.31 -12 37 19.0 17.5 N EJ027D90
0015P C2008 04 28.78638 23 02 33.02 -12 10 37.3 17.4 N EJ027D90
0015P C2008 04 28.79848 23 02 36.10 -12 10 18.9 17.5 N EJ027D90

According to the Minor Planet Center's website "Dates of last observation of comets" it was last observed on:
2002 03 30.42 14.0 T 340

W. H. Finlay (Royal Observatory, Cape of Good Hope, South Africa) discovered this comet with a 7-inch equatorial on 1886 September 26.83 (G. Kronk)

It's interesting to notice that, due to the proximity to Earth of its orbit (15P/Finlay is a Jupiter-family comet in a low inclination orbit just outside Earth's orbit), comet Finlay has been studied by several authors as a potential candidate for meteoroid delivering.

D.A.J. Seargent discussed a potential relation of the famous Murchison meteorite fall with 15P/Finlay:

http://tinyurl.com/3vmjt8

"Lubor Kresak identified comet 15P/Finlay as a likely source of meteor storms in the period 2004-2064. Neslusan and coworkers searched for photographed orbits in the IAU database, expecting activity around september 24, but no orbit could be linked to this comet. Martin Beech found that in the years 2001 and 2008 some meteoroids can make it toward the Earth's orbit, but Earth is not a the right time at that spot to cause a meteor outburst. (P.Jenniskens, 2006, chap. 19)

In a paper published in 1993, Z. Sekanina investigated about the orbital anomaly of 15P/Finlay (and few other periodic comets) as a result of the temporary activation of new discrete sources in cometary nuclei:

http://tinyurl.com/5k4zo9

The recovery image is available here:

http://tinyurl.com/6c47pq

by Ernesto Guido and Giovanni Sostero

References

G. Kronk, http://www.cometography.com/pcomets/015p.html
P. Jenniskens (2006), Meteor Showers and their Parent Comets
L. Kresak (1992), Meteor Storms. Meteoroids and Their Parent Bodies

Saturday, May 3, 2008

Comet C/2008 J1 (BOATTINI)

IAU Circular nr.8940, issued on 2008, May 3, announces the discovery by Andrea Boattini of a new comet (his second) named C/2008 J1 (BOATTINI).

It was picked-up with the 0.68-m schmidt of the "Catalina Sky Survey" on 2008, May 2.46, and it has been described by the discoverer as having a coma diameter of nearly 50 arcsec, and a fan-shaped tail 2 arcmin long toward PA 235 deg.After posting on the Minor Planet Center's 'NEOCP' webpage, a number of observers performed follow-up of this object.The undersigneds observed it through the 0.45-m, f/4.4 reflector + CCD of the Remanzacco Observatory (Italy) on 2008, May 3.0: we noticed a small compact coma, almost 15 arcsec in diameter, having a total magnitude of 14.7 (m2 nearly 15.5); an apparent tail spans almost 35 arcsec toward PA 280 deg.

Our image is available here:
http://tinyurl.com/5r2aco

Preliminary orbital elements from the Minor Planet Center (http://tinyurl.com/4d7pcj ) show that this object moves along a parabolic orbit (i= 46 deg, q= 1.5 AU); perihelion has been reached in the middle of March 2008. According the current ephemerids, the new comet "Boattini" will decrease its brightness as it will recede from both, Sun and Earth.

Congratulations to Andrea Boattini!

UPDATE (04 May 2008)

This is the discovery image of C/2008 J1 (Boattini) courtesy of Andrea Boattini:

http://tinyurl.com/52hehp

(30 seconds exposure by 0.68-m Schmidt + CCD)

by Virgilio Gonano, Giovanni Sostero and Ernesto Guido