215 research outputs found
The Hetu'u Global Network: Measuring the Distance to the Sun Using the June 5th/6th Transit of Venus
In the spirit of historic astronomical endeavors, we invited school groups
across the globe to collaborate in a solar distance measurement using the rare
June 5/6th transit of Venus. In total, we recruited 19 school groups spread
over 6 continents and 10 countries to participate in our Hetu'u Global Network.
Applying the methods of French astronomer Joseph-Nicolas Delisle, we used
individual second and third Venus-Sun contact times to calculate the distance
to the Sun. Ten of the sites in our network had amiable weather; 8 of which
measured second contact and 5 of which measured third contact leading to
consistent solar distance measurements of 152+/-30 million km and 163+/-30
million km respectively. The distance to the Sun at the time of the transit was
152.25 million km; therefore, our measurements are also consistent within
1sigma of the known value. The goal of our international school group network
was to inspire the next generation of scientists using the excitement and
accessibility of a rare astronomical event. In the process, we connected
hundreds of participating students representing a diverse, multi-cultural group
with differing political, economic, and racial backgrounds.Comment: 19 pages; 7 Figures; 1 Table; Accepted for publication in Astronomy
Education Review (AER) For more information see
http://www.das.uchile.cl/~drodrigu/easter/index_en.htm
Low-mass Tertiary Companions to Spectroscopic Binaries. I. Common Proper Motion Survey for Wide Companions Using 2MASS
We report the first results of a multi-epoch search for wide (separations greater than a few tens of AU), low-mass tertiary companions of a volume-limited sample of 118 known spectroscopic binaries within 30 pc of the Sun, using the Two Micron All Sky Survey Point Source Catalog and follow-up observations with the KPNO and CTIO 4 m telescopes. Note that this sample is not volume complete but volume limited, and, thus, there is incompleteness in our reported companion rates. We are sensitive to common proper motion companions with separations from roughly 200 AU to 10,000 AU (~10ˮ → ~ 10'). From 77 sources followed-up to date, we recover 11 previously known tertiaries, 3 previously known candidate tertiaries, of which 2 are spectroscopically confirmed and 1 rejected, and 3 new candidates, of which 2 are confirmed and 1 rejected. This yields an estimated wide tertiary fraction of 19.5^(+5.2)_(–3.7)%. This observed fraction is consistent with predictions set out in star formation simulations where the fraction of wide, low-mass companions to spectroscopic binaries is >10%
- …