Comet-like appearance of (596) Scheila

CBET nr.2583, issued on 2010, Dec. 12, announced the discovery of a spiral like structure around main belt asteroid (596) Scheila by Steve Larson in the course of Catalina Sky Survey (CSS) through the Catalina 0.68-m Schmidt telescope, on images obtained on 2010, Dec. 11.4. The cometary appearance has been confirmed by other observers.

In the Catalina images, the "coma" is bright (Vtotal~13.5), and extends some 2 arcmin north and 5 arcmin west from the central condensation.

We have been able to confirm this object remotely, using a 0.43-m f/6.8 reflector + CCD located in Nerpio (Spain): on December 12.01, co-adding of 7 unfiltered exposures, 60-seconds each, shows a wide spiral like tail. The longest part of this spiral tail is 1' in PA 280 while the small part is 30" in PA 22. You can see our image below:




According to the "Dictionary of Minor Planet Names" by Lutz D. Schmadel, (596) Scheila was discovered on 1906 Feb. 21 by A. Kopff at Heidelberg. Named in honor of an acquaintance of the discoverer, an English woman student in Heidelberg. (596) Scheila is a main-belt asteroid inclined roughly 14 degree on the ecliptic and it is now 3.1AU from the Sun and 0.8AU out of the ecliptic. With an absolute magnitude H8.9 the estimated diameter is 113Km.


Orbit Diagram of (596) Scheila:

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=596&orb=1

So this object is a potential new member of the recently recognized class of main-belt comets introduced by Jewitt & Hsieh in 2006 . These objects are remarkable for having both the orbital characteristics of asteroids and the physical characteristics of comets: they look like comets because they show comae and tails but they have orbits interior to Jupiter's and Tisserand parameters substantially larger than 3, like asteroids.

The Tisserand parameter of (596) is T_jup = 3.209

UPDATE - December 12, 11:30 UT

We have imaged again (596) Scheila at 08:20UT of December 12, 2010, this time remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. Below you can see the new image - stack of 8x120sec exposures:

by Ernesto Guido & Giovanni Sostero

Bright Sungrazing Comet on November 17-19, 2010

Only few days after the bright sungrazing comet of November 13/14, another new bright comet diving into the Sun has been discovered on Nov. 17 by Michal Kusiak using the images taken by SOHO spacecraft. This object too belong to the famous Kreutz-group, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach.

LASCO C2 Image - November 19, 2010

(Credit: SOHO)

C2 Movie (click on the thumbnail for a bigger version)

(Credit: SOHO)

We've had many bright Kreutz comets this year... A sign of a big one on its way?

Recently, different studies (Sekanina & Chodas 2007; Knight & Hearn 2008) have shown that the flow of Kreutz comets (correct of all systematic errors) increased. In the years since 1997 to 2002 for the Kreutz comet brighter that eighth magnitude has been calculated an average of about 83 new discoveries each year, while in the period 2003 - 2007 the average annual discovery rate risen to 125. This increase also applies to the findings of comets brighter than sixth magnitude where there was a increase in the flux of comets around 80%.

Sekanina and Chodas (2007) noted the increase in raw discoveries and suggested it may be “an early warning of another cluster of bright sungrazers approaching the Sun in coming decades.”

On November 18, 2010 the leading expert on Kreutz comets (reduced the observations of almost all of SOHO's ~1950 comets), Brian Marsden passed away after a prolonged illness. He will be remembered as contributing much to celestial mechanics and the dynamics and orbits of minor bodies of the solar system and as having an encyclopedic knowledge of the history of astronomy. Obituary on Sky & Telescope website and on mpec 2010-W10

by Ernesto Guido

Bright Sungrazing Comet on 13/14 November 2010

A new bright comet diving into the Sun has been discovered on Nov. 13th by Masanori Uchina using the images taken by SOHO spacecraft. This object belong to the famous Kreutz-group, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach.

Several sungrazing comets are discovered each year in SOHO images, many of them are very small and faint while sometimes some bigger and bright fragments arrive in the proximity of the Sun.

As expected, this sungrazing comet has not survived the close encounter with the sun.

C2 Image - November 14 ,2010

(Credit : SOHO)

C2 Movie (click to see a bigger version)

(Credit : SOHO & Spaceweather)

You can read more details about other recently 2010 bright SOHO comets here:

http://remanzacco.blogspot.com/2010/10/new-bright-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/04/new-bright-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/01/bright-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/01/new-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/03/new-sungrazing-comet.html

by Ernesto Guido

Evolution of the morphology of comet C/2010 V1

The recently discovered comet C/2010 V1 (Ikeya-Murakami) has been probably discovered thanks to an outburst. In fact IAUC 9183 reports that Kaoru Ikeya swept the comet's position also on Nov. 1, but did not see the comet down to mag 9-10, despite better conditions than on the 2nd. Moreover the evolution of its coma morphology is rapidly changing from night to night.

Here you can see our last image of this comet (stack of 10X30seconds exposures) obtained on 2010 Nov. 08.5, remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD.

Below an animation showing the evolution of the morphology of comet C/2010 V1 (Ikeya-Murakami) starting from our first image dated Nov. 04 to the last image dated Nov. 08, 2010 (in the animation the image of Nov. 7 is not present due to cloudy sky):

by Ernesto Guido & Giovanni Sostero

Comet 103P/Hartley by EPOXI

As most of you already know, NASA's Deep Impact spacecraft (renamed EPOXI) successfully flew 700 kilometers away from comet 103P/Hartley on Thursday November 04, 2010. This comet is the fifth comet nucleus visited by a spacecraft (the other four are: Halley, Tempel 1, Borrelly and Wild 2).

"Early observations of the comet show that, for the first time, we may be able to connect activity to individual features on the nucleus," said EPOXI Principal Investigator Michael A'Hearn of the University of Maryland, College Park.

Below you can find the flyby images released until now.

Montage showing the comet approached by the spacecraft. The sun is to the right.

(Credit: NASA/JPL-Caltech/UMD )

Close-up view of comet 103P/Hartley taken by NASA's EPOXI

(Credit: NASA/JPL-Caltech/UMD )

Image showing jets and where they originate from the surface of comet

(Credit: NASA/JPL-Caltech/UMD )

Below an image montage showing all the five comet nucleus visited by a spacecraft. Comet 103P/Hartley is by far the smallest and has the most activity in relation to its surface area.

(Credit: NASA/JPL-Caltech/UMD )

The analysis of the data acquired is underway and more revelations about comet 103P/Hartley are expected.

Congrats to the all the EPOXI team for this spectacular flyby!!

by Ernesto Guido

Comet C/2010 V1 (Ikeya-Murakami)

The new bright morning comet announced yesterday has been officially designated C/2010 V1 (Ikeya-Murakami). The mpec 2010-V46 with the first and preliminary orbit has been issued and it shows the perihelion already on Oct. 18, 2010, at about 1.7 AU.

Today we performed again some follow-up of this bright object to obtain more astrometric measures that are important to compute a reliable orbit. Below you can see the image (stack of 10X20seconds exposures) obtained on 2010 Nov. 05.5, remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. It's still evident the strong central condensation and the elongation toward PA 295.

According to COCD webpage this is the 7th visual comet discovery for Ikeya (co-discoverer also of the famous 1965's sungrazer Comet Ikeya-Seki) and the 2nd for Murakami.

by Ernesto Guido & Giovanni Sostero

New Bright Comet: "2010 V1"

IAUC nr.9175, issued on 2010, Nov. 03, announces the visual discovery of a new bright comet by two Japanese amateur astronomers, Kaoru Ikeya and Shigeki Murakami. The new comet has been designated "2010 V1". The orbit is still not available, it will be ready when more astrometric observations will be available.

This is the second visual comet discovery of 2010, after the discovery in March of comet C/2010 F4 by Don Machholz.

We performed some follow-up measurements of this object few hours ago, on 2010 Nov. 04.5, remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. Our stackings shows a coma diameter of nearly 2 arcminutes, elongated toward PA 295 and a strong central condensation.

This comet is currently at a solar elongation of only 32 degree with a ccd magnitude around 12 and a visual magnitude around 8.

Congratulations to Ikeya and Murakami for this discovery!!

by Ernesto Guido & Giovanni Sostero

Comet 103P/Hartley

Tomorrow November 04, at 13:50 UTC the Deep Impact spacecraft (renamed EPOXI for this extended mission) will have a close encounter with the comet 103P/Hartley. At closest approach (roughly 700 kilometers), the spacecraft imager named MRI (Medium Resolution Imager) will achieve about 7 meters per pixel, and the nucleus should appear about 170 pixels across. When EPOXI will reaches the comet, it will be nearly 1.1 astronomical units away from the Sun and only 0.15 astronomical units from Earth.

Comet 103P/Hartley was discovered by Malcolm Hartley in 1986 at the Schmidt Telescope Unit in Siding Spring, Australia. It belongs to the Jupiter family of comets (orbital period of 6.47 years) and it has a nucleus of about 2 km. So far only 4 comet nucleii have been explored by a spacecraft (Halley, Tempel 1, Borrelly and Wild 2), but comet 103P is unlike the others.

Discovery image (1986)

(U. K. Schmidt Telescope Unit, Siding Spring Observatory)

According to principal investigator Mike A'Hearn: "Comet Hartley 2 is smaller yet much more active than others comets. Although its core is only 2 km wide—about, a third the size of Tempel 1, it is spewing five times more gas and dust." The EPOXI team observed a strange activity on the comet in September: the abundance of CN in the comet's atmosphere jumped by a factor of five over an eight day period but there was no corresponding increase in dust. This was unexpected and never been seen in a comet before. In fact usually a gas surge is accompanied by a dust increment too.

(Credit: EPOXI)

To help the EPOXI team in their rendez-vous with the comet, the astronomical community (amateurs & professionals) are imaging the comet.

WISE spacecraft imaged the dust trail of 103P/Hartley on May 10, 2010. The dust trail (not to be confused with with the dust tail) is a "path of particles that the comet leaves during each of its trips through the inner solar-system". The extent of the trail seen in this view, behind the comet, is 1.8 million kilometers.

(Credit: WISE)

The comet was imaged on September 25, by the Hubble Space Telescope (HST). At the time of the Hubble observation, the comet was 1.153 astronomical units (172 million km) from the Sun and 0.218 astronomical units (32.6 million km) from Earth.

(Credit: NASA, ESA, and H. Weaver)

At the end of October 2010 (from 24 to 31 Oct.), the Arecibo planetary radar system was used to make images of comet 103P/Hartley. The radar delay-Doppler images obtained show the nucleus to be a highly elongated, bilobate object with a long-axis dimension of at least 2.2 km. The images give a preliminary rotation period estimate of 18.1 +/- 0.3 hours, although a less likely period of 13.2 hours cannot be ruled out.

(Credit: Arecibo - NAIC)

Below you can see a graph showing the preliminary results of the Italian Sezione-Comete /CARA regarding the trend of the Afrho parameter of 103P/Hartley in this apparation. For comparison in the graph there are also observations from the 1997/1998 apparition:

(Credit: CARA)

This is a list of all the observers who contributed to this graph with their observations: Paolo Bacci, Walter Borghini, Erik Bryssink, Dario Castellano, Gianni Galli, Ernesto Guido, Bernhard Hausler, Nick Howes, Rolando Ligustri, Herman Mikuz, Giannantonio Milani, Martino Nicolini, Carmen Perrella, Jure Skvarc, Giovanni Sostero, Roberto Trabatti.

Below you can see an image of 103P/Hartley imaged by N. Howes with the 2.0 meter Faulkes Telescope North (FTN) and processed by M. Nicolini using the Median Coma Model (MCM) developed by himself. The MCM filter creates an artificial coma, based on the photometry of the original image, and subtract the original image itself in order to highlight the internal zones of different brightness that are very close to the inner core and that would normally be hidden from the diffuse glow of the comet:

In the anti-solar direction (from bottom center right), we see the brightest part of the coma that extends to form the tail. But the most interesting thing is in the direction of sunlight (from the center to the top left) where there is obviously some sort of "jet" With a PA (Position Angle) of about 50 degrees.

On Oct. 26, the spacecraft's two cameras, a High-Resolution Imager (HRI), and a Medium-Resolution-Imager (MRI), caught two jets firing off the comet's surface over a 16-hour period.

While waiting for the exciting flyby of tomorrow here a recent image of 103P/Hartley imaged on October 11, 2010 by E. Guido & G. Sostero:

by Ernesto Guido

Follow-up of 164P/Christensen

On 2010, Oct 28.47, we were able to secure some additional follow-up about the faint returning comet 164P/Cristensen. The images were obtained through the Faulkes Telescope South (Siding Spring, Australia), a 2.0-m f/10.0 Ritchey-Chretien + CCD.

At the time of our observation the comet was about 70 deg above the horizon, in a moonless sky. Under good seeing conditions (FWHM of nearby field stars about 1 arcsec) we stacked several R filtered exposures, 60-sec each, and found the comet moving at the expected postion: 164P/Christensen was a starlike object, at about magnitude R~ 20.

Its measured astrometry was in good agreement with our previous recovery data batch of 2010, Oct 7 and 11 (see our previous post here).

We kindly acknowledge the Faulkes Telescope Project for the telescope time we used.

by N. Howes, G. Sostero and E. Guido

Bright Close Approach: 2003 UV11

The asteroid designated 2003 UV11 was discovered on October 21, 2003 by B. Skiff during the LONEOS survey with a 0.59-m Schmidt. According to its absolute magnitude (H=19.3) this object has an estimated diameter of roughly 400-500 meters, so it is a relatively large near-Earth asteroid. 2003 UV11 will have a close approach with Earth on 2010 October 30 when it will be within 0.013 AU (~5 lunar distances). The asteroid will reach a magnitude around 12 over the next few days (28/30 October 2010), becoming an easy target for small-medium sized telescopes + ccd.

We have been able to follow-up 2003 UV11 on October 28 at 07:00UT (01:00am local time) through the GRAS network, using a scope located in Mayhill (NM). Below you can see our animation composed of 15 unfiltered exposures, 10-seconds each obtained by means of a 0.25-m, f/3.4 reflector + CCD:

Please click on the thumbnail for the bigger version (~15MB size):

While this is a composite image obtained by adding 15x10sec exposures images:

When we shoot our image this rock was at 0.030 AU from Earth and speeding at about 30"/min, shining at about magnitude 12.3. At the moment of its close approach on October 30, this object will be moving roughly at 160"/min.

2003 UV11 will be observed with the Arecibo and Goldstone radars on Oct. 30, 2010, when it will be a very strong radar target.

By Ernesto Guido & Giovanni Sostero

New Bright Sungrazing Comet

A new bright comet (designated SOHO-1932) diving into the Sun has been discovered on Oct. 19th by Bo Zhou using the images taken by SOHO spacecraft. This object belong to the famous Kreutz-group comet, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach.

Several sungrazing comets are discovered each year in SOHO images, many of them are very small and faint while sometimes some bigger and bright fragments arrive in the proximity of the Sun.

SOHO-1932

(Credit : SOHO)

SOHO-1932 in C2 (long, thin tail is well over a million-km long in this image)

(Credit : SOHO)

Animation of SOHO-1932 (click on the thumbnail for a bigger version)

(Credit : SOHO & Spaceweather)

You can read more details about other recently 2010 bright SOHO comets here:

http://remanzacco.blogspot.com/2010/04/new-bright-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/01/bright-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/01/new-sungrazing-comet.html

http://remanzacco.blogspot.com/2010/03/new-sungrazing-comet.html

by Ernesto Guido

New Comet: P/2010 U2 (HILL)

IAUC nr.9174, issued on 2010, Oct. 18, announced the discovery of a new periodic comet by R. E. Hill through the Catalina 0.68-m Schmidt telescope, on images obtained on 2010, Oct. 17.3. The new comet has been designated P/2010 U2 (HILL).

We performed some follow-up measurements of this object while it was still listed in the NEO-CP, on 2010 Oct. 17.5 and 18.3, remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD.

Analysis of two different series of 10 unfiltered stacked images, 120-seconds each, showed that this object appeared non-stellar. Through our images, we were unable to discriminate a definitive coma, however we measured on both nights its FWHM nearly 40% wider compared to that of nearby field stars of similar brightness, indicating a slightly diffuse nature at the threshold limit of our instrumental set-up and seeing conditions.

In our stackings of both nights, there was also a hint of elongation in a south-west to north-east direction (or the other way around, not easy to tell), while the field stars had an ordinary symmetrical profile. This might indicate the presence of a little tail or elongated coma, below our resolving power for that night (and, indeed, the discoverer reported a thin tail about 15"-20" long in p.a. 240 deg).

Our confirming image (click below for a bigger version):

This object was previously reported in a "one stand" night of observations by the "La Sagra" sky Survey, with observations dating back to 2010, oct. 1.1

Preliminary orbital elements published by the Minor Planet Center, assign to P/2010 U2 an elliptical orbit, with: T = 2010 Nov. 9.746 TT, e = 0.40365, q = 2.55669 AU, Peri. = 44.270 deg, Node = 357.247 deg, i = 16.910 deg, equinox 2000.0, P = 8.9 years

by E. Guido, G. Sostero, L. Donato & V. Gonano

Recovery of Comet 164P/Christensen

MPEC 2010-T98, issued 2010 October 13, reports our recovery of comet 164P/Christensen. We found the comet on October 07 and October 11, 2010 at about magnitude 20.4. We imaged it remotely from D96 code (Moorook) using a 0.15-m f/7.3 refractor + CCD.

On 2010, Oct.11 the seeing conditions at Moorook (Australia) were exceptional, so we had the chance to identify the comet at the very limit of our capabilities, as a faint dot of light (magnitude about 20.4). Then, knowing where to look for, we searched in our archive images, and found it again in our stackings of 2010, Oct. 7; then we had the astrometry over two nights, that was fitting pretty well the expected orbit of 164P.

However comet 164P/Christensen is much fainter (more than 3 magnitudes) compared to the predictions.

Our recovery image (details on image):

Comet 164P/Christensen was last observed (before our recovery) on June 18, 2005 by G96 (Mt. Lemmon Survey).

by G. Sostero, E. Guido, L. Donato & V. Gonano

Small Asteroid FlyBy: 2010 TD54

The small asteroid 2010 TD54 passed at about 45,500 kilometers above the Earth on October 12, 2010. The asteroid was discovered on October 09, 2010 by one of the telescope of the Catalina Sky Survey.

According to NASA JPL website, this small object is estimated to be about 5 to 10 meters wide. 2010 TD54 has zero probability of impacting Earth. Anyway objects of these size are expected to burn up high in the atmosphere and cause no damage to Earth's surface.

We have been able to follow-up 2010 TD54 few hours before its closest approach, on October 12 at 07:00UT (01:00am local time) through the GRAS network, using a scope located in Mayhill (NM). Below you can see our animation composed of 3 unfiltered exposures, 120-seconds each obtained by means of a 0.25-m, f/3.4 reflector + CCD:

Click below for a bigger version:

Below you can see a single 120-second exposure showing the asteroid as a trail among the field stars:

When we shoot our image this rock was speeding at about 220"/min, shining at about magnitude 15.6

By Ernesto Guido & Giovanni Sostero

New Comet: P/2010 T1 (McNAUGHT)

IAU circular No. 9172, issued on October 05, 2010, announces the discovery by R. H. McNaught of a diffuse comet on CCD images obtained with the 0.5-m Uppsala Schmidt telescope. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18.5 magnitude object, designated P/2010 T1 (McNAUGHT).

We have been able to confirm this object remotely, using a 0.15-m f/7.3 refractor at the Tzec Maun Observatory (near Moorook, Australia): on October 5.6, co-adding of 16 unfiltered exposures, 300-seconds each, shows a coma nearly 7-arcsec in diameter with a central condensation, and a broad fan-shaped tail about 12-arcsec long toward PA 310.

Our confirming image (click below for a bigger version):

The preliminary orbit for comet P/2010 T1 (McNAUGHT) shows perihelion on November 24, 2010, at about 3.2 AU. The period is about 10.2 years.

This is the 57th comet discovered by McNaught.

by G. Sostero, E. Guido, L. Donato & V. Gonano

New Comet: C/2010 S1 (LINEAR)

IAU circular No. 9170, issued on September 24, 2010, announces the discovery by the LINEAR survey of an apparently asteroidal object found to show cometary appearance by other CCD astrometrists. The discovery observation was obtained by LINEAR on Sept. 21.3 UT with a 1.0-m f/2.15 reflector + CCD. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18 magnitude object, designated C/2010 S1 (LINEAR).

We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.: on Sept. 24.3, co-adding of 18 unfiltered exposures, 120-seconds each, show that this object appears soft compared to nearby field stars of similar brightness with a slight elongation in the east-west direction.

Our confirming image (click on the image for a bigger version):

The preliminary orbit for comet C/2010 S1 (LINEAR) shows perihelion on May 09, 2013, at about 4.4 AU.

According to COCD website, this is the 199th comet discovery for LINEAR.

by Ernesto Guido & Giovanni Sostero

New Comet: P/2010 R2 (LA SAGRA)

IAU circular No. 9169, issued on September 20, 2010, announces the discovery by La Sagra Sky Survey (LSSS) of a new comet on Sept. 14.9 UT with a 0.45-m f/2.8 reflector. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18.4 magnitude object, designated P/2010 R2 (LA SAGRA).

We have been able to confirm this object remotely, using a 0.15-m f/7.3 refractor at the Tzec Maun Observatory (near Moorook, Australia): on Sept. 17.6, co-adding of 12 unfiltered exposures, 300-seconds each, show a condensed coma nearly 10-arcsec in diameter.

Our confirming image (click on the image for a bigger version):

According to the IAUC No. 9169 & the latest orbital elements on MPEC 2010-S28, this object appears to be another "main-belt comet", similar to 133P = (7968) Elst-Pizarro.

This is the 4th discovery for the amateur survey La Sagra. Congratulation to the LSSS team members. The full discovery story has been posted on LSSS website.


by G. Sostero, E. Guido & L. Donato

Recovery of Comet 123P/West-Hartley

MPEC 2010-R111, issued 2010 Sept. 14, reports our recovery of comet 123P/West-Hartley. We found the comet on September 12, 2010 at magnitude 19.8. We imaged it from Malina River Observatory, Povoletto (B90) using a 0.25-m f/10 reflector + CCD.

We performed the second night of follow-up on September 13, 2010. In our stackings the comet appears shows a narrow tail about 15-arcsec long toward PA 267

Our recovery image (details on image):

Please click on the image for a bigger version.

Comet 123P/West-Hartley was last observed (before our recovery) on July 20, 2004 by Siding Spring Survey (E12).

by G. Sostero, E. Guido, L. Donato & V. Gonano

Asteroids Flyby: 2010 RF12 & 2010 RX30

Two small asteroids (2010 RF12 & 2010 RX30) will pass within the Moon's distance of Earth today, September 08, 2010. Both objects were discovered by the professional "Catalina Sky Survey" on September 05, 2010 with the 1.5-m telescope at Mount Lemmon in Arizona.

According to Nasa JPL website, 2010 RX30 has a value of H=27.1 and is estimated to be 10 to 20 meters in size and will pass within 0.6 lunar distances of Earth (about 248,000 km) at 9:51 Greenwich standard time. While 2010 RF12 With an absolute magnitude of H=28.1 is estimated to be 6 to 14 meters in size will pass within 0.2 lunar distances (79,000 km) a few hours later at 21:12 Greenwich standard time.

Although both objects are coming inside the orbit of the Moon, there is no danger of impact!! (anyway objects of these dimensions would mostly burn up in the Earth’s atmosphere in case of an impact)

We have been able to follow-up 2010 RF12 few hours ago, on September 08 at at 06:45am UT (00:45am local time) through the GRAS network, using a scope located in Mayhill (NM). Below you can see our animation composed of 4 unfiltered exposures, 30-seconds each obtained by means of a 0.25-m, f/3.4 reflector + CCD:

Click on the thumbnail for a bigger version

While below you can see a single 120-second exposure showing the asteroid as a trail among the field stars:

When we shoot our image this rock was speeding at about 31 deg/day, shining at about magnitude 15.

By Ernesto Guido & Giovanni Sostero

Another Impact Flash on Jupiter

On August 20, 2010 a new optical flash has been observed on Jupiter. This is the third time in only 13 months that such events have been observed on the surface of this giant planet. Previous events occurred on July 19, 2009 and June 03, 2010. All these signs of impact have been recorded by amateur astronomers.

Masayuki Tachikawa, amateur astronomer from Japan, first reported his detection of the flash on August 20, 2010 at 18:22 UT with a Philips ToUcam Pro II attached to his 6-inch (150-mm) Takahashi TAO-150 f/7.3 refractor. Below you can see the detection image and the video showing the flash.

Credit: Masayuki Tachikawa

Credit: Masayuki Tachikawa

After the announcement by Tachikawa, another amateur astronomer from Japan, Aoki Kazuo, looking back at his Jupiter data taken independently, found what is the confirmation of the flash. In this case the two observers were separated by roughly 800 km, so Earth and its surrounding can be rule out as cause of the flash. These flashes are likely from meteors or small asteroid impact (~ less than 10 meters).

Credit: Aoki Kazuo

Like the event of June 03, this fireball did not produce any visible scar on the surface of Jupiter. (while the July 2009 event was detected just for the scar it left on Jupiter surface, due to a bigger impactor).

Thanks to their skill and new video cameras available on the market, amateur astronomers are now able to record short exposure videos necessary to detect these short-live events. It's now time to establish a worldwide network of telescopes to monitor Jupiter 24/7 to determine the current impact rate.

by Ernesto Guido

Recovery of comet P/2003 S2 (NEAT) = P/2010 P5

IAUC circular No. 9162, issued on August 17, 2010 announces our recovery of comet P/2003 S2 (NEAT) = P/2010 P5.

We found the comet on our first attempt to locate it on August 15, 2010. It was moving roughly 6 arc-minutes away from the nominal position at magnitude 19 (roughly 1 magnitude dimmer than predicted). We imaged it remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.

We performed the second night of follow-up on August 17, 2010. Co-adding of 24 unfiltered exposures, 120 seconds each, showed the presence of a faint 15" tail in p.a. 356 deg.

Our recovery image of P/2003 S2 (NEAT)

According to the IAUC, the indicated correction to the prediction by B. G. Marsden on MPC62880 is Delta(T) = -0.33 day. The linked orbital elements by G. V. Williams and an ephemeris appear on MPEC 2010-Q08.

P/2003 S2 was last observed (before our recovery) on February 18, 2004.

By Ernesto Guido & Giovanni Sostero

Perseids 2010

The Perseid 2010 peak was expected on the night of August 12-13 between 18h and 07h UT with a ZHR (Zenithal Hourly Rate) of ~100 meteors per hour. (ZHR is a number that assumes a dark sky and the shower radiant at the zenith).

According to the first and preliminary results published on the IMO website, the observed ZHR maximum has been around 80-90 Perseids per hour in good agreement with the previsions of the dust stream models. The Perseid meteor shower is associated with the comet 109P/Swift-Tuttle. When the dust particles, spread out all along its orbit by this comet, strikes Earth's atmosphere, we see Perseids in the sky. The ZHR change accordingly to the Earth passing distance to the nearest comet dust trails and to its density. (the Perseid 2009 had a ZHR ~200)

Perseids 2010 - Activity Profile (courtesy IMO)

While the ZHR is decreasing, this meteor shower is not over yet and will last for the next few days.

Below you can find a meteor composite image (because the images were collected over several hours, the radiant of the shower is spread out) + animation. The images have been collected by our meteorcam located in Castellammare di Stabia (Italy) from 21h UT of August 12, 2010 to 03h UT of August 13, 2010. Most of this meteors are Perseids.

by Ernesto Guido

The Kamil Impact Crater in Egypt

An Italian-Egyptian team reported in July 22nd's edition of Sciencexpress, their detection in southern Egypt of an impact crater 45 meters in diameter and 16-meter-deep with a pristine rayed structure. Italian researcher V. De Michele, first found the crater in February 2009 during a Google Earth images survey. After that, an expedition was arranged to the area where this surprisingly "fresh" crater is located. In the area surrounding the crater the researchers found many tons of meteorites confirming the impact nature of this crater.

Newly discovered Kamil crater in Egypt

Largest recovered mass (ca. 80 kg!) at Kamil Crater

Including Kamil Crater, to date we know of only 176 impact craters on Earth's surface of which only 15 are less than 300 meters wide. This is due to erosion. The small craters lost their features and become unrecognizable. The Kamil crater is an exception because this is an extremely "fresh" impact crater and it escaped severe weathering (Italian-Egyptian researcher estimates the age at less than 5000 years). It is so well preserved that the radial streaks of ejecta thrown out during impact are still visible (usually these streaks are visible only on impact crater formed on body without an atmosphere and so with no weathering).

Due to its peculiarities this discovery is particularly important to better understand the impact science and to better assess the frequency of asteroid impacts on our Planet.

This is the official website of the Kamir Crater with more info and photos:

by Ernesto Guido

Remanzacco Observatory - Blog of Note

On July 20, 2010 our blog has been chosen by Blogger team as Blog of Note!!

We are happy for this award that arrive after 2 years and half (with 140 posts present at the moment, most with original material of our observations) from the creation of this blog devoted to Astronomy and in particular to Comets and Asteroids.

Thanks to Blogger and to everyone expressing their congratulations!!

Ernesto Guido