Apollo asteroid 2008 HW1

M.P.E.C. 2008-H35, issued on 2008 Apr. 28, 18:44 UT, announces the discovery of 2008 HW1, an Apollo asteroid in a very comet-like orbit (Tj nearly 2.4; Jupiter family comets have Tisserand parameter TJ between 2 and 3). It was picked-up by the staff of Lincoln Laboratory ETS through a 1.0-m f/2.15 reflector + CCD, on 2008 April 25.35091. After its posting on the NEO Confirmation Page, further follow-up was secured by a number of observers. 

According the preliminary orbital elements published by the Minor Planet Center, 2008_HW1 moves along a very elongated orbit (e~0.96), that takes a little more than 4 years to be completed; at aphelion it approaches the orbit of Jupiter (Q~ 5 AU), while at perihelion (that will be reached in middle of next June) is passes only 0.1 AU - or nearly 15 Million Km - from the Sun. This is a rock whose diameter is supposed to range from nearly 600-m to 2-Km (depending on its surface reflectivity).

We performed some follow-up on 2008, April 28.0, from the Remanzacco Observatory (MPC #473):

In spite of its very comet-like orbit, in our stackings (total exposure time of 30 minutes) this object appears perfectly stellar, with no hints of any detectable coma or tail within our seeing limit.

by L. Donato, M. Gonano, V. Gonano, E. Guido, V. Santini and G. Sostero

Comet P/2008 G2 (SHOEMAKER)

IAUC nr. 8939, issued on 2008, April 24, announces the recovery of P/1995 J3 = 1994k = 1994 XXVIII (Shoemaker), providing it the new designation P/2008 G2 (SHOEMAKER). It was picked up by T. Spahr, analyzing the astrometry of Apr. 10, reported by the Catalina Sky Survey (observer: R.A. Kowalsky, no comments about any potential cometary appearance) to the Minor Planet Center; linkage to further archive data of Apr.1 was provided by B. G. Marsden. The object was reported as having a magnitude of about 18.6.

We performed some follow-up of this comet on 2008, Apr. 24.9 from the Remanzacco Observatory (details on image; click on it for a bigger version):

From our stacking we have evidence of a tiny coma, nearly 10 arcsec in diameter, possibly elongated toward North-West. The measured total magnitude is about 18.5 (R unfiltered).

Perihelion of P/2008 G2 (Shoemaker) will occur in April 2009. At that time the comet will have m1 nearly 17. The maximum brightness is expected to be just half a magnitude better, in August 2009, when the comet will mostly be a southern object.

by Giovanni Sostero & Ernesto Guido (AFAM-CARA, Italy)

New Comet C/2008 H1 (LINEAR)

CBET No. 1343, issued on April 20th, announces the discovery by the Lincoln Near Earth Asteroid Research team of a 18.th magnitude comet in Ursa Minor officially designated C/2008 H1 (LINEAR).

It was picked-up on 2008, Apr. 18.34722 with a 1.0-m, f/2.15 reflector + CCD located in New Mexico (USA). After its posting on the Minor Planet Center's 'NEOCP' webpage, several observers performing its astrometric follow-up, reported about its cometary nature: in particular, E. Reina (April 19.0, Masquefa Observatory, Spain) commented about a magn. 16.6 coma almost 25 arcsec in diameter, and a 43 arcsec tail toward P.A. 233 deg. J. M. Aymami (April 19.8, Observatorio Carmelita, Spain) mentioned a suspected coma elongated toward P.A. 209 deg, while R. Apitzsch (April 19.8, Wildberg, Germany) noticed a tail toward southwest.

On April 19.5 we performed our own confirmation images, remotely through a 0.25m, f/3.4 reflector + CCD from the Rent A Scope network (Mayhill station, NM). The sky was clear, however the full Moon increased quite a lot the sky backgound noise; moreover, due to some technical problems, we couldn't stack more than 20 single unfiltered exposures, hampering our detections of very faint details. Anyway, also on our image, below the trail of a faint field's star, it's possible to appreciate the presence of this new comet, with the typical diffuse shape of this kind of objects.

With some image processing, from our image it's possible to notice a central condensation, surrounded by a ~30 arcsec diameter very faint coma, elongated toward South-West (details on image):

A photometric analysis perfomed via Roberto Trabatti's Winafrho software (CARA's dedicated data reduction package), provides m2~ 18 (Ru) for the central condensation, and m1 ~16.5 (Ru) for the total coma brightness. The Afrho parameter (proxy of dust abundance within the coma) upper limit for this comet is then estimated to be nearly 90 +/- 30cm; considering that C/2008 H1 currently is at almost 2.8 A.U from the Sun past perihelium, this result seems to point toward a comet of modest activity.

Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-H09 show that this object moves along a very elongated and tilted orbit (e= 1, i= 76 deg); perihelion occured on 2008, March 11, with q~ 2.8 AU. According to the ephemerids, for the next few months this object will remain mainly a northern hemisphere target, and it will decrease its brightness from V~ 16.8 to nearly V~ 18.

by Ernesto Guido & Giovanni Sostero

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