Eric G. Hintz
Matthew W. Collier
Michael D. Joner
1998
<p>We report 15 new times of maximum light for the δ Scuti star IP Virginis (formerly known as SA 106‐1024). An analysis of all times of maximum light indicates that IP Vir has been decreasing in period at a constant rate of −<span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00001.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00001.gif" alt="" /></span> days day<sup>−1</sup>. Evidence is also presented that IP Vir is a double‐mode variable with a period ratio of <span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00002.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00002.gif" alt="" /></span> . This period ratio predicts a [Fe/H] value of −0.3. From photometric (<i>uvby</i>β) observations, we find a foreground reddening of <span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00003.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00003.gif" alt="" /></span> .008 mag and a metallicity of [Fe/H] = +0.05. It is shown that [Fe/H] = −0.3 is most likely the correct value. Intrinsic <span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00004.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00004.gif" alt="" /></span> ‐ and <i>c</i><sub>1</sub>‐values, plotted in a model atmosphere grid, indicate a mean effective temperature, <span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00005.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00005.gif" alt="" /></span> K, and a mean surface gravity, <span class="jstor-math NLM_tex-math" data-img-url="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00006.gif"><img class="mathImg" src="http://www.jstor.org/literatum/publisher/jstor/journals/content/publastrsocipaci/1998/pasp.1998.110.issue-746/316156/production/images/eqs/eq-00006.gif" alt="" /></span> . All of these physical parameters support Landolt's initial conclusion that IP Vir is an ordinary δ Sct star.</p>
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10.1086/316156
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Astronomical Socety of the Pacific
Photometric studies of δ Scuti stars. I. IP Virginis
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