منابع مشابه
The Yale Embryo
In 1934 a fourteen-day-old embryo was discovered during a postmortem examination and became famous for being the youngest known human embryo specimen at the time. The embryo was coined ?the Yale Embryo,? named after the location where it was discovered, Yale University [4] in New Haven, Connecticut. During the early twentieth century, the rush to collect embryos as well as to find younger and y...
متن کاملMicrolens Parallaxes with SIRTF
The Space Infrared Telescope Facility (SIRTF) will drift away from the Earth at ∼ 0.1 AU yr. Microlensing events will therefore have different characteristics as seen from the satellite and the Earth. From the difference, it is possible in principle to measure ṽ, the transverse velocity of the lens projected onto the observer plane. Since ṽ has very different values for different populations (d...
متن کاملThe Frequency Distribution of Some Measured Parallaxes and of the Parallaxes Themselves.
It is well known that the frequency functions of a set of quantities and of their measures are different;' if the error of measurement is comparable in magnitude to the quantity determined, they may be decidedly dissimilar. In the case of good photographic parallaxes the reported probable errors average about eight one-thousandths of a second of arc, making a dispersion of twelve. Moreover, as ...
متن کامل20. Verification of Parallaxes
Hipparcos parallaxes will play a major role in the astrophysical applications of the Hipparcos results and in this respect their accuracy is more important than their precision, at least for all the investigations of statistical character. In this Chapter, the systematic errors of the Hipparcos astrometric parameters, including the parallaxes, are evaluated by examining the possible sources of ...
متن کاملFinding “absolute” parallaxes directly
We develop the formalism for estimating parallaxes, proper motions and positions from long-focus astrometric observations as well as additional extraneous reference material whenever this is available and relax the constraints on the star parameters (basically their sums and correlations with the coordinates on the frames), thus generating (albeit correlated) quasiobservations whose inclusion w...
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ژورنال
عنوان ژورنال: Science
سال: 1907
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.25.645.749