Periods of 25 Variable Stars in the Small Magellanic Cloud

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Harvard Circular 173 relates measured stellar periods to brightness.

When interpreting its table and graph, examine sample selection and the distance assumption.

The 1912 publication is a bounded starting point for examining how a numerical relationship is presented. The 25 stars in its title define a study sample, not a universal inventory of all variable stars. Connect the contribution described in the biography to this work’s table, graph and explanation. A digit visible in a scanned page is not automatically a newly verified machine-readable measurement. Record row and column location, mark uncertain readings and check the original units. That preserves the route from a historical record to any modern plot you produce from it.

When comparing period and brightness, inspect whether an axis shows period or its logarithm. The direction of the brightness scale also matters: a larger magnitude is not a brighter star. Assuming approximately common distance within one cloud helps explain a relative comparison but does not remove every uncertainty. If fitting a relationship, record the method, sample size and excluded points. Recreating the appearance of a historical graph and independently testing the accuracy of its original measurements are different projects. State which level your work has reached instead of allowing the polish of a new diagram to imply additional verification.

The original full-view link is preserved, although access may not always work identically. Harvard’s institutional person record supplies a supporting route into the publication’s context. This page does not claim specialist rechecking of every table cell. An advanced study could compare the publication, an accessible plate record and a modern variable-star dataset as separate sources. Keep dates and calibration differences explicit. A useful question asks not only whether the relation can be plotted again but under which observing conditions it can be used reliably. Include failed and uncertain cases rather than retaining only examples that fit an expected line.

Other names / spellings: 1912HarCi.173….1L · Cepheid · Sefeid