2024 Occultations by Special Main-Belt Asteroids - Updated 2024 June 28
Thousands of occultations by GAIAMOON and other asteroids added for the rest of 2024
These occultations are described and illustrated in this .pdf document, updated with maps and a table emphasizing the newly-added special objects. Read that document to learn about the new GAIAMOONS project, formulated after finding astrometric signatures of probable binary asteroids following the occultation discovery and confirmation, and the Gaia additional characterization of the duplicity of (4337) Arecibo in 2021. Many new special asteroids are added from the GAIAMOONS project, but there are also several other new objects added, including 3 binary asteroids found from occultation observations during the first two months of this year. The .pdf document includes several hot links to external Web pages, but links to internal files, especially the .xml input files used by the Occult program, are given below. The map and table, and some other information given in the .pdf file, were published on page 249 of the Observers Handbook for 2024, which has been available since last December. _ _ _ _ _ The important occultation of EI Tauri by (253) Mathilde, half of which was imaged by NASA's NEAR spacecraft in 1997, is described here with prediction information for the event. The occultation was observed as summarized below; the sky-plane plot and final report of the event are not yet available: Dist. from center, km 26.0 km north: Vadim Nikitin in Kentucky, no observation 13.4 km north: near Wilmington, NC, 1.44s occ'n recorded with 11in. scope by Univ. of VA students Andrey Moore, Eleanor Press, and Nicholas Velasquez 0 km: Roger Venable northern attended station in s. NC, 1.7a occ'n 11.7 km south: Ted Barnes at T.A. Obs. near Oak Ridge, Tenn., positive 26.5 km south: Roger Venable, southern remote station in s. NC, miss Their locations are shown approximately on this Occult Watcher map. _ _ _ _ _ OCCULTATIONS BY (10424) GAILLARD, A NEW PROBABLE BINARY ASTEROID On January 14th, Jean-Francois Gout recorded this double occultation of a 13.0-mag. star by this asteroid from Mississippi. In his account, he suggests that the asteroid might be binary and gives links to details of his observation and analysis. He also made rotational light-curve observations that helped confirm the binary hypothesis. Gout found a good occultation of an 11.0-mag. star on Mar. 26 at 1.4h UT visible from a path passing from Dallas to just north of Miami (as far as we know, that event was not observed due to poor weather). More observations of occultations by Gaillard will be useful to determine the nature of the object. In my last update in April, I found 135 occultations of stars brighter than mag. 16 that will occur during the rest of 2024, but most of those will occur over areas with few occultation observers. An Occult input file was given for them, but is not included now since they are in the new (green) non-GAIAMOONS Occult input files given below. _ _ _ _ _ OCCULTATIONS BY (90) ANTIOPE This is a binary asteroid with equal large (~90km) components 171 km apart. Special procedures are needed to show paths of occultations by the separate components, which is crucial for these events; often only a miss by both components will occur at the central line of an uncorrected prediction. Antiope will occult 8.8-mag. HIP 34749 on Aug. 19, only visible from part of northeastern Florida, but at Jacksonville, the occultation will occur at 8:30 UT but only 8 deg. above the eastern horizon, in azimuth 68 deg.; an unusually clear sky will be needed to observe that event from locations along the Atlantic coast. On Dec. 27 around 7h UT, Antiope will occult an 11.2-mag. star with the path from s. Brazil to s. Peru. There will be 33 occultations of stars of mag. 14.0 or brighter visible around the world in 2024 by Antiope, but many of those are over oceans or other astronomically unpopulated places. _ _ _ _ _ As noted in the .pdf document, (52246) Donaldjohanson is a Lucy-mission main-belt asteroid flyby target on its way to the Jupiter Trojans, so observations of occultations by it will be valuable. No bright occultations by it will occur in North America in 2024, so none are shown on the map and in the table of the .pdf document. However, there will be occultations of 13th-mag. stars by the object on Sept. 2 (WY,ND,nwMN, and swON), Sept. 5 (n. FL), and Oct. 5 (NS-sUT), but their durations are less than 0.15s, rather like NEA occultations, so large portable scopes will be needed to reliably detect these events. Worldwide, there are 14 occultations by Donaldjohanson of stars of mag. 12.0 and brighter, and six of stars brighter than mag. 11.0. On Sept. 30 before 4h UT, Donaldjohanson will occult a 9.3-mag. star from a narrow path crossing Senegal to Chad. _ _ _ _ _ CORRECTIONS TO THE OBSERVERS HANDBOOK 2024 The USA edition of the 2024 RASC Observers Handbook left out the column labels for all of the tables of occultations by asteroids on pages 245 to 251, an error that crept in just before the print run and after (correct) galley proofs had been sent to me for review. Corrected .pdf pages are posted on the website of the RASC Handbook. Another problem, spotted by Joan, is an updated link for Occult Watcher, on p. 246, 7th line counting up from “Occultations by Near-Earth Asteroids” the link given there can not be used to access the current version of the software. After I submitted the old link, Steve Preston created a better page for Occult Watcher that gives much information about it, as well as the link for the current version. This update is noted on the RASC 2024 Handbook updates page. Not yet on the RASC correction page are the following: On p. 248, 2nd line of “Occultations by Special Main-Belt Asteroids”, there are no spaces between any of the words on that line. I’m not sure how this happened, it is OK (with appropriate spaces) in the Word file I submitted, but this error is in all of the proof .pdf’s that were sent to me in late August and early Sept. I should have seen it in those, but missed it, as apparently did all the other reviewers; Joan found this last night. In Table 3 on p. 249, the Deimos occultation listed on Sept. 23 will actually be on Oct. 7, and the Anitra occultation given as Oct. 7 will actually be on Nov. 7. _ _ _ _ _ Much useful information is also given on a special page I set up for the Asteroids, Comets, and Meteors (ACM) conference held in Flagstaff, AZ last month. It includes a link to my presentation given there about NEA and other special occultations, to a much longer version of that presentation given on July 9 by Zoom to the ChesMont Astronomical Society, to several abstracts and ePosters relating to occultations from the ACM Web site, and to much general occultation information suitable for those interested in getting started with observing occultations. _ _ _ _ _ OCCULT INPUT .XML FILES FOR 2024 When you open these files with your Web browser, you should get a display that looks like this. The larger files may take a couple of minutes to show this appearance, showing a messed-up display before then. Once the proper view appears, right-click anywhere on the display, then "Save as" to a directory on your computer; the best directory is the \Asteroid\ subdirectory in your Occult\ directory. Earlier Files, posted in January: For 123 special main-belt asteroid events to mag. 14 in N. America Worldwide special main-belt events to mag. 14, 1907 occultations, but does include (319) Leona, so use this file to find Leona occultations in your region. When you open this file with Occult, you can filter by asteroid number, so just type "319" and check the box to its left under "Asteroid number" in the orange box, second from the right side of "Selection Filters" and you'll list only the occultations by Leona. For North America during the rest of 2024, the only Leona path will cross only Key West, FL and some of the Bahamian islands on Apr. 1, with the star mag. 13.4, and the star has a huge (8.9) RUWE. Worldwide, there are 43 Leona occultations during 2024; the best are occultations of 10th-mag. stars visible from northern S. America on March 13 and April 6. New Files, for GAIAMOON (red in the .pdf) objects and other new (green) objects: 46 occultations by GAIAMOON & other new objects to mag. 13 for North America. 1153 occultations by non-GAIAMOON new objects to mag. 16 for the rest of 2024 worldwide. 12,948 occultations by GAIAMOON & other new objects to mag. 16 for the rest of 2024 worldwide. The bright main-belt occultations page contains additional explanatory information not repeated here; it also has links to other pages, such as one for occultations by Near-Earth asteroids, and for occultations by Trojan asteroids. ______ David and Joan Dunham, 2024 January 29, updated April 17 and 24, and June 28. e-mail: dunham@starpower.net cell phone: 301-526-5590