Recovery of comet P/2002 LZ11 (LINEAR) = P/2009 H1 (LINEAR)

IAU Circular No. 9039, issued on 2009 Apr 19, announces our recovery of P/2002 LZ_11 (LINEAR), now designated P/2009 H1 (LINEAR); it was last observed in January 2004 (MPC code #372, Geisei).

After several frustating and unsuccessful tryings due to moonlight interference and stellar crowding (the searched comet was in Sgr) we initially picked-up P/2002 LZ11 on 2009, Apr. 17.45 through a remotely controlled telescope of the GRAS network (details on image):

http://tinyurl.com/c4wn6x

In our stacking the comet was located about 4 arcmin to the East-Northeast of the ephemerids position: co-adding of 25 unfiltered exposures, 120 seconds each, through a 0.25-m, f/3.4 reflector + CCD, revealed the presence of an extremely compact coma, about 12-arcsec in diameter, and a short tail nearly 25-arcsec long toward West.

We tried further follow-up on April 18 from the same site and from the Skylive-Grove Creek Obs. (MPC #E16), however our efforts were hampered due to the star crowding and to the unsuitable observing conditions (a magn. 19 comet seen through amateurs instrumentation, needs a pretty good sky).

Hopefully we were more lucky using the 0.37-m, f/14 reflector + CCD of the Iowa Robotic Observatory near Sonoita, AZ ((MPC# 857) over the same night: co-adding of 20 unfiltered exposures, 120 seconds each, showed the presence of a tiny coma about 8-arcsec in diameter, with a faint extension toward West (two bright field stars were interfering with the detection of the small tail we had recorded well the day before). Our image is available here:

http://tinyurl.com/c7b2uf

According to the orbital elements published so far by the Minor Planet Center website (http://tinyurl.com/cqnamw), perihelion will occur on March 2010, with the comet at 2.4 AU from the Sun. This Jupiter-family comet moves along an elliptic orbit in about 7 years, having a semi-major axis of 3.7 AU, eccentricity of 0.35 and an inclination of 11.5 deg.

Ernesto Guido, Giovanni Sostero, Paul Camilleri and Enrico Prosperi 

Recovery of comet P/2003 H4 (LINEAR) = P/2009 F7 (LINEAR)

IAU Circular No. 9038, issued on 2009 Apr 15, announces the recovery P/2003 H4 (LINEAR) = P/2009 F7 (LINEAR) by the LINEAR team and the undersigneds; it was last observed in August 2003.

The Lincoln Near Earth Asteroid Research facility: 

http://tinyurl.com/d5w83g

picked-up P/2003 H4 on 2009, March 31 during a single-night observing session. We indipendently found the return of this object on 2009 April 15.60 through one remotely controlled telescope of the "Skylive" network, located at Grove Creek (near Trunkey, Australia). 

In our images (stacking of 30 unfiltered images, 60-seconds each, with a 0.35-m f/7 reflector + CCD), the comet showed a diffuse coma about 15-arcsec in diameter, with a central condensation, having m2 about 19.6.

The recovered comet was about 8 arcmin East, South-East to the ephemerids positions, located in Hydra.

Here you can found our recovery image of April 15, 2009:

http://tinyurl.com/dn568m 

Afterwards we performed some further follow-up from different observing sites and instruments, that confirmed the aspect of this object. 

Like the Iowa Robotic Observatory (MPC# 857) 20x60 stack of images, obtained on 16 April 2009:

http://tinyurl.com/c8nm39

or the GRAS stacking, obtained on the same night under good seeign conditions (details on image):

http://tinyurl.com/dlol8m

According to the orbital elements published so far by the Minor Planet Center website (http://tinyurl.com/c8k56q), perihelion will occur on June 2009, with the comet at 1.7 AU from the Sun. This Jupiter-family comet moves along an elliptic orbit in 6.1 years, having a semi-major axis of 3.3 AU, eccentricity of 0.49 and an inclination of 18 deg.

We would like to thank the Grove Creek-Skylive staff for their kind support during this recovery.

by Giovanni Sostero, Enrico Prosperi, Ernesto Guido & Paul Camilleri 

New Comet 2009 F6

IAUC Circular No. 9034, issued on 2009, April 6, announces the discovery by R. D. Matson of a new comet from analysis of ultraviolet SWAN-SOHO images obtained on 2009, Mar. 29, 31, Apr. 1, 3, and 4.

We undertaken a first try to locate this object from the private observatory of one of us on (about) Apr. 6.1; however we were unsuccessfull, due to some hardware problems with the telescope.

Afterwards we were able to confirm the existence of this comet remotely, through the GRAS network, using a scope located in Mayhill (NM): on 2009, April 6.5, co-adding of 10 unfiltered exposures, 60 seconds each, obtained by means of a 0.25-m, f/3.4 reflector + CCD, shown a diffuse coma about 2.5 arcmin in diameter, with a sharp central condensation about 20 arcsec in diameter. The magnitude of the central condensation was measured to be at about 14 (unfiltered CCD), while the total magnitude m1 has ben established to be about 11 (unfiltered CCD).

Stacking a total of 20 minutes exposure time, through equalization of the histogram, we can trace a coma diameter of nearly 5 arcmin; image enhancing techniques (azimuthal median subtraction and 1/r theoretical coma subtraction) show the presence of a short extension toward North-East, emanating from the central condensation (hint of a tail, or elongation of the coma?).

Our image is available here:

http://tinyurl.com/co95my

At the time of this writing, no orbital elements of this comet has been published by the Minor Planet Center. A preliminary calculation, performed by the undersigneds running through FindOrb the observation currently available at the the NEO-CP webpage, gives the following (approximate) orbital solution:

q= 1,3 AU, e= 1, Incl.= 85.5 deg, Peri.= 129.5 deg, Node= 279 deg.



UPDATE (07 April 2009, 14:00 UT)

IAUC Circular 9035 has been released and the new comet is now officially designated C/2009 F6 (YI-SWAN).

According to this IAUC, Dae-am Yi (Yeongwol-kun, Gangwon-do, Korea) has contacted H. Yamaoka, on March 28, informing him about his discovery of a possible comet through a Canon 5D camera + 90-mm telephoto lens. The available astrometry indicate that this is the same object of comet 2009 F6. So, the double denomination.

An Mpec with a preliminary parabolic orbital elements and an ephemeris has been issued too:

http://www.cfa.harvard.edu/mpec/K09/K09G21.html


UPDATE (07 April 2009, 21:00 UT)

Our image of comet C/2009 F6 (YI-SWAN) rendez-vous with open cluster NGC 7789:

http://tinyurl.com/d7h7aj

by Ernesto Guido, Giovanni Sostero & Paul Camilleri

Recovery of P/2001 MD7 (LINEAR) = P/2009 F3 (LINEAR)

IAU Circular No. 9031, issued on 2009 Mar 20, announces the recovery of comet P/2001 MD_7 = COMET P/2009 F3 (LINEAR) by the undersigneds; it was last observed in April 2002.

We picked up this object on 2009 Mar 17, 18 and 20 through a couple of remotely controlled telescopes, located in New Mexico and Australia. The comet appeared as a pale glow, magnitude about 18, nearly 15 arcsec in diameter.

The recovered comet was very close to the ephemerids positions, however its detection has been a little problematic, because it was rather low in the morning sky just before twilight, located in a rich star field in Sgr. We took several nights of observations to locate it, fighting with clouds and moonlight interference.

Here you can see our image of March 22, 2009:

http://tinyurl.com/czgnts

According the orbital elements published by the Minor Planet Center, perihelion will occur in September 2009, with the comet at 1.25 AU from the Sun; at that time P/2009 F3 (LINEAR) will reach about magnitude 12. This object moves along an elliptic orbit in 7.9 years, having a semi-major axis of 3.97 AU, eccentricity of 0.68 and an inclination nearly 13.5 deg.

We thanks the Mayhill-GRAS and Grove Creek-Skylive staff for the kind support they provided us for this tricky recovery.

by Ernesto Guido, Giovanni Sostero & Paul Camilleri

New comet C/2009 E1 (ITAGAKI)

M.P.E.C. 2009-E68  issued on 2009 March 15, announced the discovery by K. Itagaki of a new comet:

http://www.cfa.harvard.edu/mpec/K09/K09E68.html 

We performed some follow-up of this object while it was posted in the NEO-CP.

Since the candidate was too low to be imaged from the Remanzacco Observatory (MPC #473), on 2009, Mar. 15.1 we connected to the GRAS network, and imaged it remotely from Mayhill (NM), details on image:

http://tinyurl.com/banwdh  

The initial stacking produced a trailed image of the central condensation, because the expected proper motion was slightly off. After some trials, we found the suitable speed and PA able to produce a sharp image of the comet.

Stacking our frames (co-adding of 30 unfiltered exposure, 30 seconds each) we noticed an obvious comet, with a central condensation having about magnitude 14.6 (unfiltered R), a bright inner coma, having a diameter of about 1.4 arcmin, and faint external halo nearly 4 arcmin in diameter, slightly elongated toward South-West. The total magnitude m1 we measured was about about 11.0 (unfiltered R).

From the preliminary orbital elements published by the MPC:

http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2009E1.html 

we understand that this comet moves along a parabolic, retrograde, orbit (i= 126 deg, q= 0.6 AU). Perihelion will be reached in the beginning of next April 2009, with m1 about 10. Unfortunalety comet ITAGAKI will stay at small elongation from the Sun, so it will be a difficult object to be observed.

K. Itagaki found it from his private observatory of Takanezawa-Tochigidi with a 0,2-m f/3, reflector + CCD camera at (about) 09h UT on 2009, March, 14.

Congratulations to Itagaky-san for his nice gift: there are still some opportunities for dedicated amateur comet catchers, in spite of the professional surveys!

by Ernesto Guido, Giovanni Sostero e Paul Camilleri 

(AFAM, Osservatorio di Remanzacco)

Foreshortening effects on C/2007 N3 (LULIN)

Comet C/2007 N3 (LULIN) was a nice show in late February this year, when it passed relatively close (nearly 0.42 AU, on Feb. 24th). At about its perigee, another phenomena occurred: its phase angle reached a minimum value, then it quickly started to grow-up again. Nearly simultaneosly we witnessed an abrupt change in the appearance of the comet, due to the consequent foreshortening effect: the ion tail, in a matter of hours, switched from North-West to South-East.

Possibly another, less cospicuous, change in comet's LULIN aspect may be under course: according to our follow-up, some effects of the foreshortening change seems to be readily visible also in a series of images we secured from various sites & through with different scopes, in the past few weeks.

As you may notice from the following panels, the prominent feature (kind of "fan" structure) originating from the central condensation toward South-West (i.e. at about PA 220 deg), plus a secondary one, toward North-East (i.e. at about PA40 deg) that was reported by several observers, visible till March 2nd, now seems to be over:

March 11th: http://tinyurl.com/acq7wr

March 2nd: http://tinyurl.com/d8bnfc

Februaty 27th: http://tinyurl.com/cpslxs

February 19th: http://tinyurl.com/bgt6yd

More data need to be secured to definitely clarify the situation, however at a first glance we have the impression that this might be a foreshortening effects as well. Apparently, the changing geometry really plays a strong role, when interpreting the inner coma details sometimes reported on comets (alleged fans, jets, etc.).

by Giovanni Sostero, Ernesto Guido, Paul Camilleri & Virgilio Gonano

Curious coma-tail of C/2007 Q3 (Siding-Spring)

Recently we imaged C/2007 Q3 (Siding Spring), remotely with a "Skylive" scope from Grove Creek (Australia):

http://tinyurl.com/amgcvn

details on picture.

Through image processing, the comet show a funny effect: at low contrast, an asymmetric coma is seen, about 45 arcsec in diameter, with an obvious elongation toward (about) East (PA 90 deg). In high contrast, a broad tail, nearly 80 arcsec long, became obvious; but it points toward South-West, at about PA 230 deg (i.e., in nearly opposite direction)!

Further image processing, capable to extract possible inner coma features (azimuthal median subtraction, 1/r theoretical coma subtraction) confirms the presence of an asymmetric coma, with a possible feature exing toward East, North-East, developing in a counterclockwise direction.

Preliminary photometric analysis of our frames, show a total m1 magnitude of about 13, while the sharp central condensation shine at m2 about magnitude 15 (unfiltered CCD).

Comet C/2007 NQ3 (Siding-Spring) moves along a parabolic orbit, whose perihelion will be reached in October 2009, at 2.2. AU from the Sun.

Updated orbital elements and ephemerids are available in the Minor Planet Center's Website:

http://tinyurl.com/bgbme8

by Giovanni Sostero, Ernesto Guido & Paul Camilleri