In 2019, the Research and Education Collaborative Occultation Network (RECON) obtained multiple-chord occultation measurements of two Centaur objects: 2014 YY49 on 2019 January 28 and 2013 NL24 on ...2019 September 4. RECON is a citizen-science telescope network designed to observe high-uncertainty occultations by outer solar system objects. Adopting circular models for the object profiles, we derive a radius km and a geometric albedo for 2014 YY49 and a radius km and a geometric albedo for 2013 NL24. To the precision of these measurements, no atmosphere or rings are detected for either object. The two objects measured here are among the smallest distant objects measured with the stellar occultation technique. In addition to these geometric constraints, the occultation measurements provide astrometric constraints for these two Centaurs at a higher precision than has been feasible by direct imaging. To supplement the occultation results, we also present an analysis of color photometry from the Pan-STARRS surveys to constrain the rotational light curve amplitudes and spectral colors of these two Centaurs. We recommend that future work focus on photometry to more deliberately constrain the objects' colors and light curve amplitudes and on follow-on occultation efforts informed by this astrometry.
Abstract
A stellar occultation by the extreme large-perihelion trans-Neptunian object (541132) Leleākūhonua (also known by the provisional designation of 2015 TG
387
) was predicted by the Lucky Star ...project and observed with the Research and Education Collaborative Occultation Network on 2018 October 20 UT. A single detection and a nearby nondetection provide constraints for the size and albedo. When a circular profile is assumed, the radius is
km, corresponding to a geometric albedo
, for an adopted absolute magnitude of
H
V
= 5.6, typical of other objects in dynamically similar orbits. The occultation also provides a high-precision astrometric constraint.
A stellar occultation by the extreme large-perihelion trans-Neptunian object (541132) Lele k honua (also known by the provisional designation of 2015 TG387) was predicted by the Lucky Star project ...and observed with the Research and Education Collaborative Occultation Network on 2018 October 20 UT. A single detection and a nearby nondetection provide constraints for the size and albedo. When a circular profile is assumed, the radius is km, corresponding to a geometric albedo , for an adopted absolute magnitude of HV = 5.6, typical of other objects in dynamically similar orbits. The occultation also provides a high-precision astrometric constraint.
Assessing Motion Graphs Palmquist, Bruce C.
The Science teacher (National Science Teachers Association),
11/2001, Letnik:
68, Številka:
8
Journal Article
Recenzirano
Issues are presented concerning the difficulties which are often experienced by science students when they are required to obtain information from motion graphs. The teaching of motion graph ...information assessment is discussed.
Abstract
In 2019, the Research and Education Collaborative Occultation Network (RECON) obtained multiple-chord occultation measurements of two Centaur objects: 2014 YY
49
on 2019 January 28 and 2013 ...NL
24
on 2019 September 4. RECON is a citizen-science telescope network designed to observe high-uncertainty occultations by outer solar system objects. Adopting circular models for the object profiles, we derive a radius
km and a geometric albedo
for 2014 YY
49
and a radius
km and a geometric albedo
for 2013 NL
24
. To the precision of these measurements, no atmosphere or rings are detected for either object. The two objects measured here are among the smallest distant objects measured with the stellar occultation technique. In addition to these geometric constraints, the occultation measurements provide astrometric constraints for these two Centaurs at a higher precision than has been feasible by direct imaging. To supplement the occultation results, we also present an analysis of color photometry from the Pan-STARRS surveys to constrain the rotational light curve amplitudes and spectral colors of these two Centaurs. We recommend that future work focus on photometry to more deliberately constrain the objects’ colors and light curve amplitudes and on follow-on occultation efforts informed by this astrometry.
Beschrieben wird ein Testverfahren, bei dem jeweils drei Studenten mündlich geprüft werden. Jedem dieser Studenten wird eine Frage gestellt und die Antwort bewertet. Anschließend geben alle Studenten ...noch Kommentare zu dieser Frage, was wiederum mit einer Punktzahl bewertet wird. Die Endnote jedes einzelnen Studenten setzt sich aus der individuellen und der gemeinschaftlichen Leistung zusammen.
Hunt et al describe an activity that they call Juan's dilemma, an extension of the familiar lemon-battery activity. The activity integrates oxidation and reduction chemistry with circuit theory in a ...fun, real-world exercise. The activity is designed for a ninth-grade physical science class, and the students have found it to be intriguing and challenging.
JUAN'S DILEMMA: A new twist on the old lemon battery Hunt, Vanessa; Sorey, Timothy; Balandova, Evguenia ...
The Science teacher (National Science Teachers Association),
10/2010, Letnik:
77, Številka:
7
Journal Article
Recenzirano
When life hands you lemons, make a battery! In this article, the authors describe an activity they refer to as "Juan's Dilemma," an extension of the familiar lemon-battery activity (Goodisman 2001). ...Juan's Dilemma integrates oxidation and reduction chemistry with circuit theory in a fun, real-world exercise. The authors designed this activity for a ninth-grade physical science class, and their students have found it to be intriguing and challenging. (Contains 6 figures and 3 online resources.)
PDF
