Southern Maine Astronomers
12-03-2020
Monthly “Zoom” Meeting
1830: Social gathering prior to start of meeting allows discussion among those attending of divers topics including the increasing Star Link satellites and their impact on visual and imaging astronomy, video astronomy as a method of star parties with less risk of infection and better results, current near Earth object identified as the booster for Surveyor 2 and astrometric analysis enabled back tracking it to its launch or there about.
Attending: Rob Burgess, Russell Pinizzotto, Ara Jerahian, Robert Dodge, Joan Chamberlin, Paul Howell, James Shields, Forrest Sumner, Al DiSabatino, Roy Patrice, Greg Thorup, Dwight Lanpher, Rowan Goebel-Bain, Ron Thompson, John Saucier, Bernhard Reim, Jon Wallace, R. Aileen Yingst, and George Bokinsky
1900: Rob Burgess called to meeting to order and introduced the guest speaker Dr. R. Ilene Yingst currently with the Planetary Science Institute in Tucson, AZ but working from her home in Maine and being a principal researcher on the Dawn Mission to the asteroids Vesta and Ceres beginning in 2007 with data being analysis ongoing to this time.
1910: Vesta by Dr. R. Aileen Yingst
Dr Yingst’s presentation “Big News From a Dwarf Planet: The Story of Vesta” began with the discovery of the minor planet Vesta on March 29, 1807 by the German Astronomer Heinrich Wilhelm Matthias Olbers and that Olbers gave the naming of the asteroid to Carl Friedrich Gauss whose mathematical calculations allowed the determination of its orbit. Vesta was named in honor of the Romas goddess of hearth and home.
Interesting fact about Vesta include is diameter of 280 km, making it slightly larger than Pallas but it is 25% more massive constituting ~9% of the asteroid belt. Vesta has a differentiated interior, and is the brightest asteroid seen from Earth with apparent magnitude 5.1 to 8.48, and absolute magnitude of ~3.2. Temperature on Vesta have been calculated to be 85° K at minimum and 270° K at maximum. Vesta is smaller than Ceres at 939 km, but slightly larger than Pallas at 512 km and Hygiene at 434 km. Together the four represent the largest asteroids. Vesta is different in features than the other three.
Vesta is dense fro an asteroid but it’s in the same neighborhood as far less dense objects. Observations suggested a rocky surface, with the possibility of past “geologic” activity leading to a metallic core of Iron and Nickel, an Olivine-rich mantel, and a crust of Plutonic rocks and basalt with diogenetic intrusion.Heat was necessary for differentiation over time.
Understanding the evolution of Vesta would give a broader model of evolution of other bodies Moon and Earth’s geology. This was described by a discussion of differentiation of Vesta based upon detection of diogenite, olivine and low Ca eucrite. A cut meteorite with these features enabled its origin to be traced to Vesta.
Vesta’s mission was to (1) capture the earliest moments in the evolution of the Solar System; (2) determine the nature of the building blocks from which the terrestrial planets formed; and (3) contrast the formation and evolution of two small planets that followed very different evolutionary paths.
The Dawn Spacecraft was described along with the nature of the NASA supported low cost missions originating outside of NASA. The Dawn Mission was the first investigation at close range of two large protoplanets ( 1 Ceres and 4 Vesta) that represent icy and rocky end members of the Asteroid population. Dawn’s cameras provided images of the Vestan surface with resolution 500X anything previously achieved. The instruments included the Dawn Framing Camera: clear and color filter camera, visible and IR camera, and the Gamma Ray and Neutron Detector (GRaND). The last to determine the abundances of major rock-forming elements including oxygen, magnesium, calcium, aluminum, silicon, titanium, and iron along with potassium, thorium, uranium, and water.
Dawn arrived at Vesta on July 16, 2011 and Departed for Ceres on September 5, 2012.
Dr Yingst presented a series of images of Vesta’s surface taken with the various cameras completing a mosaic of its surface with analysis of surface features including craters assessments of the ages of the craters, ejects patterns, effects of Vesta’s rotation, and surface analysis. The presentation ended with a look to the future with conclusion that “The scientists want to go back.”
2020: Perseus by Dr. Russell Pinizzotto.
Russ Pinizzotto continued his series of monthly constellations with Perseus beginning with an image of the night sky of Perseus and its surrounding neighbors Cassiopeia, Andromeda, Triangulum, Taurus, Auriga, and Camelopardalis. The tour included the major stars Mirfak, Algol, Menkib and included in addition to the easily seen objects with the unaided eye (skies permitting) to those that can be seen through binoculars including clusters, doubles and triple stars, and those requiring telescopes of various resolutions up to imaging systems of complexity.
Attention was given to 𝛽 Perseus Algol with Joel Stebbins publication in the Astrophysical Journal in 1910 of a dimming pattern the he observed through the University of Illinois 12” refractor from 0.18 to about 1.38 over about 10 hours with a later dip about 35 hours later from 0.12 to 0.2 magnitude. This was explained by eclipsing binary of Algol Aa2 and Algol Aa! With primary eclipse time of 2.867324 days.
Clusters included the alpha Per cluster, Messier 34 (NGC 1039) open cluster, Caldwell 14 (NGC 869 , 884) open clusters, double clusters of beauty. Caldwell 24 (NGC 1275) supergiant elliptical galaxy and NGC 1023 a barred lenticular galaxy were shown. Nebulae include NGC 1497 the California emission nebula, NGC 1333 a reflection nebula. Nova Per 1902 was described and later images by Chandra and amateur astronomers was shown to reveal more recent captures of the event.
2100: Final announcements were made by Rob Burgess.
George Bokinsky