Post by Chicago Astronomer - Astro Joe on Nov 13, 2004 8:42:01 GMT -6
Asteroid Number 334 - Chicago
We have several things named after our fair city...
Chicago Style Hotdogs,
Chicago Style Pizza,
Chicago attitudes...
And now, I discover that we have an Asteroid named after us as well. Chicago belongs to a group of Asteroids called the "Hilda" asteroids. These are stable asteroids with no sign of chaotic behavior. Our asteroid is located within the great asteroid belt that lays between Mars and Jupiter...
(Personally...I think there was a planet there before, but it shattered for some reason. The asteroid belt are the remains of such body... but that will have to be explored in the "Unexplained" Board in this forum.)
Below is all the information that you ever cared to know about our Asteroid...
On 23 Aug 1892, Max Wolf discovers Asteroid #334 Chicago.
Here's some bio on him:
Maximilian Franz Joseph Cornelius Wolf (June 21 1863 – October 3 1932) was a German astronomer. He was a pioneer of astrophotography.
Working in Heidelberg, he discovered more than 200 asteroids, beginning with 323 Brucia in 1891. He pioneered the use of astrophotographic techniques to automate the discovery of asteroids, as opposed to older visual methods, as a result of which asteroid discovery rates sharply increased. In time-exposure photographs, asteroids appear as short streaks due to their planetary motion with respect to fixed stars.
Among his many discoveries was 588 Achilles (the first Trojan asteroid) in 1906, as well as two other Trojans: 659 Nestor and 884 Priamus . He also discovered 887 Alinda in 1918, which is now recognized as an Earth-crossing Amor asteroid (or sometimes classified as the namesake of its own Alinda family).
The Minor Planet Center credits his discoveries as "M. F. Wolf"; there is a more recent "M. Wolf" who is Marek Wolf.
He also discovered or co-discovered some comets, including 14P/Wolf and 43P/Wolf-Harrington .
He also discovered Wolf 359, a red dwarf that is one of the nearest stars to our solar system. Note that Wolf-Rayet stars were co-discovered by French astronomer Charles Wolf and not by him.
He won the Gold Medal of the Royal Astronomical Society in 1914. He won the Bruce Medal in 1930. Interestingly, the Bruce Medal and asteroid Brucia are both named after the same person, Catherine Wolfe Bruce.
A crater on the Moon is named after him, and so is the asteroid 827 Wolfiana .
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And in 2002, Asteroid Chicago Occulted a star in Gemini.
Here is an observational account from The Royal Calgary/Canadian Astronomer Association:
Shadow of the moon in Australia andsouthern Africa, shadow of 334Chicago right here at home! Andrew Lowe and I were able to contribute timings of the occultation of a star inGemini, by asteroid 334 Chicago at about 3 a.m. on December 24th.
An asteroid occultation is when an asteroid passes directly in front of a star.To an observer at the right spot on theground, the star “blinks out” for a fewseconds. Like a solar eclipse, the trackwhere the occultation is visible isnarrow. Because the star is at a hugedistance, the shadow on the earth’ssurface is an exact silhouette of theasteroid. The duration of the “blinkout”, and the observer’s location, canbe transformed into a chord across across section of the asteroid.
These simple observations are the easiest wayto determine the true size and shape ofasteroids!As usually happens, I was reminded ofthis predicted occultation by David Dunham of IOTA (Int’l OccultationTiming Association) just a day beforethe event. This was followed shortlythereafter by an email from Andrewasking if I planned to observe it?Indeed I did, and so did he! To make it sporting, I elected to use my 70 mm refractor, though I did confirm earlier in the evening that I’d be able to observe a star of that magnitude in the moon-bright sky.Since my home was predicted to be atthe southern edge of the eclipse/occultation track, I chose to observe from home. Andrew lives further souththan I do, so he asked David Dunham to assign him a position (to avoid du-plications). He observed near Olds andended up near the centre-line of theevent. Andrew thanks our club andJohn Breen for the use of a 6” f/8equatorially-mounted scope for theobservation.
Both Andrew and I had frights in thelast moments: could we find the star!?The star was bright (mag 8.4) but in abit of a featureless area south of Gemini,so it was a little hard to find (3 a.m.,remember!). I had found the star 20minutes before the event, but “lost it”,and only got back on target with aminute to spare. We both used audiotape, recording our shouts of “in” and“out”, along with a time signal: himWWV, and me, the NRC telephonetime signal immediately before andafter the occultation. When we played back our tapes, and determined thelength of the “blink”, Andrew determined he had a 12.3 second blink,and I had 10.5 seconds. This reflectsthat his line of sight was closer to beingacross the “equator” of the asteroid,and I was at “mid-latitudes”.
Our ingress times matched within abouta second, his being later, which wasconsistent with the movement of theshadow along its track.We were very pleased to learnover the following days that six otherobservers (in Maryland andPennsylvania) had timed this event, andthat Doug Hube (Edmonton) was alsoobserving, though he turned out tobe north of the track and reported amiss.Andrew has transformed all thetimings and observers’ locations intochords across the silhouette of the asteroid, and fit a circle to all the observations with absolute timings (i.e.,those observations submitted asabsolute times of ingress and egress,rather than just a duration of theoccultation). The data are fitremarkably well by a simple circle withradius 85 km – and ergo, that isthe radius of asteroid 334 Chicago,though of course, much moredata would probably show itis not exactly circular in cross-section.
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And yet more...
334 Chicago
This is the only asteroid among the Hilda asteroids observed that was found to be of C class. Our spectra (Fig. 4) have spectral slopes of 3.4, 3.4 and 1.9 %/ Å and all three values are consistent with both ECAS photometry and the spectra obtained by Vilas & Smith (1985). The obtained taxonomy (C class) agrees with Tholen (1989). Absorption edges arising from inter-valence charge transfer (IVCT) from the cation is seen in the blue part ( of the spectra. There is also indication of a broad and very shallow absorption feature centered around 7000 Å , and this is probably due to charge transfer in phyllosilicates. However, both these features are significantly less intense than those seen in spectra of CM2 carbonaceous chondrites (Vilas et al).
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And that is plenty of data on a rock named after our city.
Where's Asteroid Raquel Welch?
