Prato, 3 October 2021 – A little one meteorite, weighing approximately between 30 and 100 grams, it fell in the night between 1 and 2 October between the provinces of Prato and Pistoia. The fireball was ‘sighted’ by eight cameras of the Prisma space network located in Tuscany and central Italy.
“After the preliminary analysis of the meteor, the experts of the Prisma network, coordinated by the National Institute of Astrophysics, determined that the meteor should have fallen into an area between the towns of Lucciano (Pistoia) and Oste (Prato) – explains in a note the director of the Parsec Foundation which includes the Museum of Planetary Sciences of Prato, Marco Morelli -. And that’s where we’ll look for it. The chances of finding such a small object in a short time are very low ».
Already from tomorrow field research will begin and on Tuesday there will be an operational meeting to organize the exploration on the ground through an app that will allow you to trace the areas already sieved. «I am sure that many amateurs will join the research, any help is precious – adds Morelli -. But anyone who finds a small stone with the characteristics of a meteorite, a stone covered with a dark patina and with rounded corners, must immediately notify us, perhaps by sending a photo. The commercial value of meteorites is very low compared to the scientific one ».
«Who found or thought they had found one – the experts explain in this regard – he must not touch it with his hands, but photograph it and contact the Museum of Planetary Sciences in Prato ». In January 2020 another meteorite reported by the Prisma network was found in the countryside of Carpi (Modena).
It’s not every day that we witness an outburst from a new meteor shower gracing the skies of the Earth. But that’s just what may be in store this week for fortunate observers deep in the southern hemisphere, with the advent of the Arid meteors.
The shower in question should radiate from the otherwise obscure southern hemisphere constellation of Ara the Altar (perhaps, they should be known as the ‘Ara-tids?’ The radiant position is Right Ascension 17h 7’, Declination -57.5 degrees south.
Arid meteor activity, in CAMS’ All-Sky view. Credit: SETI/NASA Ames/CAMS
The source of the shower is short period Comet 15P/Finlay. On a 6.5 year orbit, Comet 15P reached perihelion on July 13th this past summer, and its debris trail intersects the Earth’s orbit in early October.
The worldwide CAMS meteor network. Credit: SETI/NASA Ames/CAMS.
Early observations of the Arids late last month were promising. Specifically, SETI Institute and NASA Ames Research Center astronomer Peter Jenniskens, and T. Cooper and D. Lauretta of the Astronomical Society of South Africa and the University of Arizona respectively found an uptick of 13 meteors seen in NASA Ames’ worldwide Cameras for All-Sky Meteor Surveillance (CAMS). These cameras were based in New Zealand and Chile, and caught the meteors hailing from the constellation Ara on the clear sky nights of 28-30 September. This is from debris ejected from Comet 15/P Finlay during its perihelion passage in 1995.
Two more, stronger outbursts are projected for the evening of October 6-7th (Wednesday night into Thursday morning). Luckily, the Moon reaches New phase on October 6th, putting it out of view. The first peak courtesy of the 2002 trail is expected to arrive on Oct 7th at 00:35 Universal Time (UT), with the second set for 3:55 UT. This favors the southern tip of South America, though observers across the southern hemisphere should be vigilant for any increase in meteor activity, especially from the direction of the constellation Ara near the region of the south celestial pole. Hey, the southern hemisphere needs more meteor showers…
Meteor trails evolve over time. Two good examples are the Andromedids which produced splendid outbursts in the late 19th century before fading into obscurity (the first meteor photo was of an Andromedid), and the December Geminids which are overtaking the Perseids in the early 21st century as the year’s most dependable annual meteor shower. This evolution is due to the interplay and tug of the interior solar system worlds (mainly Jupiter) on streams of debris laid down by comets during perihelion passages.
A typical CAMS all-sky meteor camera setup. Credit: SETI/NASA Ames/CAMS.
October is always an interesting month for meteors in general. In addition to a possible Arid outburst, the Taurid fireballs are active in early October, thanks to periodic comet 2P/Encke, holder of the shortest orbital period of any known comet at just 3.3 years. We’ve also got the peak for the elusive Draconids courtesy of Comet 21/P Giacobini-Zinner coming up on October 8th… though 2021 isn’t predicted to be an outburst year like 2011 and 2012. Finally, we have the Orionids on October 21st courtesy of 1P/Halley, though the Full Hunter’s Moon will interfere with the show.
The Arid radiant near local midnight, as seen from near Santiago, Chile. Credit: Stellarium.
Keep an eye out for the Arids if you happen to be in the southern hemisphere this week… you may just catch the birth of a new meteor shower in the making.
Lead image: An early Arid meteor from late September. Credit: SETI/NASA Ames/CAMS.
Main-belt comets are asteroids that present characteristics of comets. That is, they are icy and, when warmed by the sun, they release some of their material into space. The material then flows behind in comet-like tails. Hsieh explained:This behavior strongly indicates that its activity is due to the sublimation [process of changing from a solid to a gas] of icy material. As such, it’s considered a main-belt comet, and is one of just about 20 objects that have currently been confirmed or are suspected to be main-belt comets, including some that have only been observed to be active once so far.
[Object] 248370 can be thought of as both an asteroid and a comet, or more specifically, a main-belt asteroid that has just recently been recognized to also be a comet. It fits the physical definitions of a comet, in that it is likely icy and is ejecting dust into space, even though it also has the orbit of an asteroid. This duality and blurring of the boundary between what were previously thought to be two completely separate types of objects – asteroids and comets – is a key part of what makes these objects so interesting.
Hsieh continued:This extremely narrow tail tells us that dust particles are barely floating off of the nucleus at extremely slow speeds and that the flow of gas escaping from the comet that normally lifts dust off into space from a comet is extremely weak. Such slow speeds would normally make it difficult for dust to escape from the gravity of the nucleus itself, so this suggests that something else might be helping the dust to escape. For example, the nucleus might be spinning fast enough that it’s helping to fling dust off into space that has been partially lifted by escaping gas. Further observations will be needed to confirm the rotation speed of the nucleus though.
Cometary activity is generally thought to be caused by sublimation – the transformation from ice to gas – of icy material in a solar system object, which means that most comets are found to come from the cold outer solar system, beyond the orbit of Neptune, and spend most of their time there, with their highly elongated orbits only bringing them close to the sun and the Earth for short periods at a time. During those times when they are close enough to the sun, they heat up and release gas and dust as a result of ice sublimation, producing the fuzzy appearance and often spectacular tails associated with comets.