(3200) Phaethon

Phaethon is an Apollo type asteroid with many peculiarities. It has been discovered in 1983 by Green and Davies while searching images of IRAS satellite. So it is the first asteroid to be discovered by a spacecraft. Moreover the orbit is unusually short (P 1.59 yr) with a small perihelion distance of q= 0.141 AU.

In 1983, Fred Whipple identified Phaethon like the parent of Geminid meteor stream. But it has never displayed unambiguous cometary activity. Some people hold on to the opinion that Phaethon is a comet (or extinct comet), while other thinks that it is more an asteroid or the likely product of a breakup.

In a recent article has been suggested that planet-crossing object 2005 UD is dynamically similar to Phaethon and so that:

"3200 Phaethon, 2005 UD, and the Geminids are pieces of a main-belt comet precursor that disrupted, perhaps due to unsustainable internal gas"

Where main-belt comets are a new class of objects introduced by Jewitt& Hsieh in 2006. To say it with the words of Jewitt & Hsieh:

"Phaethon's true nature must still be considered an open question"

Below you can see our recent image (November 04) of this object (or click here )

by Ernesto Guido and Giovanni Sostero

References

- Meteor Showers and their Parent Comets by P. Jenniskens

- Search for activity in 3200 Phaethon by Hsieh & Jewitt (2005)

- Physical Observations of 2005 UD: a mini-Phaethon by Jewitt & Hsieh (2006)

2008 TC3 Trail imaged over Northern Sudan!!!

Today's APOD shows the impact train of 2008 TC3, captured in a video frame:

http://antwrp.gsfc.nasa.gov/apod/ap081108.html

http://zuserver2.star.ucl.ac.uk/~apod  (APOD mirror)

For more information see also:

http://asima.seti.org/

http://asima.seti.org/images/Sudantrain1.jpg

http://asima.seti.org/images/Sudantrain2.jpg

For more information about 2008 TC3:

http://remanzacco.blogspot.com/2008/10/small-asteroid-2008-tc3-to-hit-earth.html

http://remanzacco.blogspot.com/2008/10/2008-tc3-animation.html

by Ernesto Guido

2008 TC3 Update - Impact Flash Imaged from Satellite

Impact Flash Imaged from Satellite

While ground pictures of the fireball are still missing (the event occurred in a remote area over northern Sudan), it looks like finally there is an image of the impact flash.

The explosion was imaged by the weather satellite Meteosat 8.

The image is available at SpaceWeather.com: http://tinyurl.com/3r2ool

According to J. Borovicka, Astronomical Institute, Czech Academy of Sciences, the bright spot on the images taken by the weather satellite Meteosat 8 has been noticed by Z. Charvat. This bright spot likely corresponds to the atmospheric entry of 2008 TC_3 over northern Sudan (see - IAU Circular No. 8994).

Impactor 2008 TC3 entering Earth' shadow

Roughly one hour before expected atmospheric impact over northern Sudan, 2008 TC3 entered Earth' shadow becoming invisible until the impact.

The entry in the Earth' shadow has been imaged by La Sagra Sky Survey, Spain. Their nice image is here:

http://www.minorplanets.org/OLS/2008_TC3/

This image also shows a periodic light variation along the trail that indicates a fast rotation. The same effect is evident in the image obtained by italian astronomer Walter Boschin at the 3.58m diameter Telescopio Nazionale Galileo (TNG):

by Ernesto Guido

2008 TC3 Animation

Animation showing the motion of small asteroid 2008 TC3 few hours before entering Earth atmosphere. 

Images obtained at Remanzacco Observatory by G. Sostero, E. Guido & P. Camilleri.

Same animation on Youtube:

http://tinyurl.com/4o5o2u

by Ernesto Guido

Small Asteroid 2008 TC3 to hit Earth Tonight

On the morning of 06 October 2008, astronomer R. Kowalsky of Mount Lemmon Survey detected a small object (absolute magnitude H=30.4) now designated 2008 TC3.

According to NeoDys and Jpl Neo experts, the impact with the Earth atmosfere is almost certain and it should be at 0246 UTC of 07 October 2008. Fortunately this object is only a small chunk of rock few meters in size and should not survive passage through the atmosphere. In case some fragments should reach the ground, the impact zone has been located in the northern Sudan.

No damage is expected.

The entry in the atmosphere should be visible over northern Africa and possibly even over southern Europe.

Almost certainly 2008 TC3 will be the first impacting object discovered before entry into the Earth's atmosphere.

Here you can see our follow-up images of 2008 TC3 taken few hours before its entry in Earth's atmosphere  (click on the image for a bigger version):

The discovery mpec:
http://www.cfa.harvard.edu/mpec/K08/K08T50.html

By G. Sostero, E. Guido and P. Camilleri

COMET P/2008 T1 (BOATTINI)

IAUC nr. 8988, published on 2008, Oct. 2, announces the discovery of another comet (his fifth) by Andrea Boattini, named P/2008 T1 (BOATTINI). This 18.th magnitude object has been found in Pisces, during the Catalina Sky Survey search, with a 1.5-m reflector. The discoverer reported a fairly condesed coma about 10-arcsec in diameter, and a fan-shaped tail nearly 1 arcmin long, in PA ranging 245-275 deg. After its posting on the Minor Planet Center's NEO-Confirmation Page, several observers confirmed its cometary nature, remarking the presence of the above mentioned broad fan tail toward West-Southwest. We confirmed it remotely from Mayhill (NM) through a 0.25-m, f/3.4 reflector + CCD around October 2.4. Eighty stacked 60-s unfiltered CCD exposures show a coma about 10" in diameter and a broad, fan-shaped tail about 40" toward p.a. 244 deg. Click on the image below for a bigger version.

Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-T30:

http://www.cfa.harvard.edu/mpec/K08/K08T30.html

provides a solution that points toward a "Jupiter family" object, with perihelion on February 2008 (e=0.29, q~ 3.02 AU, i~ 2.1 deg). Under these circumstances, it appears that this comet has experienced a close encounter with Jupiter around June 2002. In the next future, P/2008 T1 will gradually decrease its brightness, staying not far from the ecliptic for several months to came.

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

COMET C/2008 S3 (BOATTINI)

IAUC nr. 8986, published on 2008, Sept.30, announces the discovery of a comet by Andrea Boattini, named C/2008 S3 (BOATTINI). It has been found in Taurus, during the Catalina Sky Survey search, with a 1.5-m reflector. The discoverer reported a coma having a strong condensation and a coma about 10-arcsec in diameter, elongated toward PA 115-deg, with total magnitude about 18.5. After its posting on the Minor Planet Center's NEO-Confirmation Page, several observers confirmed its cometary nature.

We imaged it remptely from Mayhill (NM) through a 0.25-m, f/3.4 reflector + CCD around Sept. 30.4 (details on image; click on it for a bigger version):

Preliminary orbital elements published by the Minor Planet Center on M.P.E.C. 2008-S96 assume a parabolic retrograde orbit with perihelion on April 2011 (e=1, q~ 3.1 AU, i~ 158 deg). It's noteworthy the fact that the comet has been discovered to be active at about 8.3 AU from the Sun; this seems to indicate a rather "alive" object also at relatively high distances from our star.

Maxim brightness is supposed to be reached in the Summer of 2011, at about magnitude 12 (well placed in the sky for both hemispheres); obviously all the previous extrapolations are based on measurements conducted upon a very short arc of orbit, so they must be confirmed by further astrometric and photometric follow-up.

by Ernesto Guido, Giovanni Sostero and Paul Camilleri