Possible Nova in Sagittarius

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

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

R.A. = 18h05m58s.90, Decl. = -27o 13'56".3 (equinox 2000.0; UCAC-2 catalogue reference stars):

by Ernesto Guido and Giovanni Sostero

Possible Nova in Cygnus

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

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

R.A. = 19h43m01s.98, Decl. = +32o 19'13".5 (equinox 2000.0; UCAC-2 catalogue reference stars):

Our multicolor photometry provides the following values: 2008, Apr. 11.36, B= +8.06, V= +7.54, R= +7.04; 2008, Apr. 11.46, B= +8.20, V= +7.77, R= +7.15 (accuracy +/- 0.05 magnitudes in each color).

by Giovanni Sostero & Ernesto Guido

New Comet C/2008 G1 (GIBBS)

IAUC nr. 8932, issued on 2008, April 9, announces the discovery of a new comet by A. R. Gibbs: C/2008 G1 (GIBBS); it was found through the 1.5-m reflector + CCD of the Mt. Lemmon Survey on 2008, April 7.36 while it was slowly moving in Serpens.

After its posting on the NEO-Confirmation Page as target "8GA7420", we performed some follow-up of this object from Remanzacco Observatory (MPC #473) and, remotely, through the Mayhill (NM) station of the "Rent A Scope" network. The best image was that obtained from Remanzacco (see below):

In our stackings from both sites, "8GA7420" showed its cometary nature, with a small coma, some 8 to 10 arcsec in diameter, and a short tail, 15 to 20 arcsec long toward South-SouthWest. The total magnitude m1 has been calculated as R~19.1, while the nuclear magnitude m2 was R~19.5. Preliminary orbital parameters published by the Minor Planet Center show that this comet moves along a parabolic orbit (e=1, i=72 deg, q= 3.7 AU). It will reach perihelion on February 2009. This comet will be mostly a northern object, and it's not supposed to get any brighter than magnitude 18.

by Ernesto Guido & Giovanni Sostero

Asteroid 2008 GS3

2008 GS3 is Aten-type Near Earth Asteroid that has been discovered by the Lincoln Laboratory ETS Sky Survey (MPC #704) on 2008, April 7.30; we performed its follow-up from the Remanzacco Observatory on 2008, April 7.9, while it was labeled as "BJ81650" in the NEO-CP webpage. At the beginning, it didn't show up in stackings, very likely because of the uncertainty of its ephemerids (the stacking we did was performed according the "best guess" preliminary speed and PA available at the moment).

On 2008 April 9.5, the object was still listed in the NEO-CP, but its ephemerids were considerably improved due to the follow-up astrometry produced by several observers. Then we re-stacked our original frames of the 7-8 April night with the new speed and PA, and we find it!

According to the preliminary orbital elements available at Minor Planet Center database, 2008 GS3 is a rock with an estimated diameter of nearly 100 meters, orbiting the Sun every 9.5 months. At perihelion it reaches at almost 80 Million Km from our star, between the orbits of Mercury and Venus, while at aphelion it approaches the Earth's orbit. When we imaged it, the asteroid was at 25 Million Km from our planet, moving at nearly 7.3 arcsec/min in Virgo, with a magnitude of nearly R~19.

Giovanni Sostero & Ernesto Guido

Comet 7P/Pons-Winnecke

Comet 7P/Pons-Winnecke is currently approaching the Sun, during its journey to the inner Solar System. On 2008, March 25.9 we imaged it from the Remanzacco Observatory (Italy): after weeks of bad weather, a storm finally cleared up the sky, so we were able to perform some follow-up of this faint comet, while it was slowing moving in Ursa Major.

In our stacking (average of 20 unfiltered exposures, 120 seconds each, through a 0.45-m f/4.4 reflector + CCD) the comet appears starlike (no coma or tail are visible; same FWHM of the field stars):

We performed a preliminary photometric analysis, that returned a magnitude of R~ 19.5; at this low level of activity, the afrho parameter (proxy of the dust abundance within the coma) is dominated by sunlight scattered by the nucleus, so it doesn't have a straightforward interpretation (just for the record, its current value is close to a few cm).

7P/Pons-Winnecke belongs to the Jupiter family cometary class (q~ 1.2 AU, Q~ 5.6 AU, i~ 22 deg, period~ 6.4 years). During its current approach, it has been recovered at magn.21 on 2007, Dec. 17 by K. Sarneczky (University of Szeged), 0.60-m Schmidt + CCD. It will reach perihelion at the end of September 2008, and it's not supposed to get any brighter than magnitude 12.5 at its best (but at small solar elongation).

C. Snodgrass et Al. [A&A 444, 287-295 (2005)] estimated the nucleus radius at ~2.2 Km, and bracketed its rotation period between 6.8 and 9.5 hours.

This comet has been related to the June Bootids meteor stream, that was pretty active during some of the comet's passages in the first quarter of the past century. However the current activity of this meteor shower is rather modest, probably because the gravitation influence of Jupiter changed significantly the orbital path of the comet and its associated meteoroid debris.

Giovanni Sostero & Ernesto Guido

Comet C/2008 E3 (GARRADD)

IAU circular nr. 8927 published yesterday, announces the discovery of a new comet by Gordon Garradd, named C/2008 E3 (GARRADD). This object has been picked-up on 2008, March 5.8 on images obtained within the Siding Spring 0.5m Uppsala schmidt reflector + CCD.

We peformed some follow-up of this object by means of a remotely controlled scope of the "RAS" network (details on image; click on it for a bigger version):

In our stacking we can appreciate a coma nearly 10 arcsec in diameter, with a strong central condensation. Through strong enhancement of the visualization parameters, a faint and extended outer halo nearly 20arcsec in diameter, possibly elongated toward North-West, seems to be visible (however it must be said that in our frames this detail is very close to the background noise, and thus must be considered as uncertain).

It's also possible to see a faint and broad tail, extending nearly 20 arcsec toward North. We measured the central condensation as m2 almost 18.4, while the 10 arcsec coma has an m1 nearly 17.7 (both are unfiltered CCD magnitudes, approximated to R).

A preliminary afrho (proxy of dust abundance within the coma) measurement provides a value close to 450 +/- 100 cm; this seems to point toward a pretty active comet, considered that it's current distance from the Sun is r~ 5.5 AU.

The Minor Planet Center database points to a (preliminary) retrograde parabolic orbital solution with an inclination on the ecliptic plane of i~ 107 degrees; perihelion will be reached at the end of next October, at 5.2 AU from the Sun.

C/2008 E3 (GARRADD) will remain a southern hemisphere object, and it's not supposed to get significantly brighter than magnitude 17.

Ernesto Guido & Giovanni Sostero

Comet C/2008 E1 (CATALINA)

IAUC 8923, published yesterday, reports the discovery of a new comet: C/2008 E1 (CATALINA). It has been picked-up with the 0.68m Schmidt + CCD of the Catalina Sky Survey on 2008, Mar. 2.14.

According the report of several astrometrist that performed its follow-up, this object is rather faint (nearly magnitude 19) and is currently showing a small coma, 6 to 12 arcsec in diameter, elongated toward North-East.

We imaged it remotely from Mayhill, NM (details on image; click on it for a bigger version):

Preliminary orbital elements published on MPEC 2008-E41 points to a parabolic orbit, with e=1.0 and Incl.=34.3 deg; perihelion will be reached at the end of October 2008 (q=4.8 AU).

This comet is not supposed to get any brighter than V~17, so it shoud remain a rather unconspicuous object, in spite of the fact that it has a significative absolute magnitude, since we are currently observing it at Jupiter's distance.

Ernesto Guido & Giovanni Sostero