<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0185-1101</journal-id>
<journal-title><![CDATA[Revista mexicana de astronomía y astrofísica]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. astron. astrofis]]></abbrev-journal-title>
<issn>0185-1101</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Astronomía]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0185-11012017000100133</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Observations and light curve solutions of the eclipsing W UMA binaries CSS J071813.2+505000, NSVS 2459652, NSVS 7178717 and NSVS 7377875]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Kjurkchieva]]></surname>
<given-names><![CDATA[Diana P.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Popov]]></surname>
<given-names><![CDATA[Velimir A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
<xref ref-type="aff" rid="Aaf"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Vasileva]]></surname>
<given-names><![CDATA[Doroteya L.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Petrov]]></surname>
<given-names><![CDATA[Nikola I.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Shumen University  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Bulgaria</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,IRIDA Observatory  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Bulgaria</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Bulgarian Academy of Sciences Institute of Astronomy and NAO ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Bulgaria</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2017</year>
</pub-date>
<volume>53</volume>
<numero>1</numero>
<fpage>133</fpage>
<lpage>140</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012017000100133&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012017000100133&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012017000100133&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Photometric observations in Sloan g&#8217; and i&#8217; bands of four eclipsing W UMa binaries are presented. They allowed the improvement of system ephemerides. The light curve solutions led to the following results: (i) CSS J071813.2+505000 is barely an overcontact system, NSVS 2459652 and NSVS 7377875 are over-contact binaries with an intermediate fillout factor, while NSVS 7178717 has a deep-contact configuration; (ii) NSVS 7178717 undergoes total eclipses while the other three targets exhibit partial eclipses; (iii) The components of each target are almost the same in temperature: those of CSS J071813.2+505000 are early G stars while those of the other three targets are of K spectral type; (iv) The targets with late components reveal spot activity; (v) NSVS 2459652 and NSVS 7377875 are W UMa binaries of H subtype; (vi) The relation mass ratio - luminosity ratio of our targets confirms the results from previous statistical analysis of W UMa systems.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Presentamos observaciones en las bandas g&#8217;e i&#8217; del Sloan de cuatro binarias eclipsantes tipo W UMa, que permitieron mejorar las efemérides de los sistemas. Con las soluciones para las curvas de luz obtuvimos los siguientes resultados: (i) CSS J071813.2+505000 es un sistema escasamente en sobre-contacto, NSVS 2459652 y NSVS 7377875 son binarias en sobre-contacto con un factor de llenado intermedio, y NSVS 7178717 esta &#769; en una configuración de contacto profundo. (ii) NSVS 7178717 presenta eclipses totales, mientras que las otras tres binarias tienen eclipses parciales. (iii) Las componentes de cada binaria tienen casi la misma temperatura: las de CSS J071813.2+505000 son estrellas G tempranas, mientras que las de los otros tres sistemas son estrellas K. (iv) Las binarias con componentes tardías presentan actividad de manchas. (v) NSVS 2459652 y NSVS 7377875 son binarias tipo W UMa, subtipo H. (vi) La relación cociente de masas-cociente de luminosidad de nuestros sistemas confirma los resultados de análisis estadísticos previos de sistemas tipo W UMa.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[binaries: eclipsing - stars: fundamental parameters - stars:]]></kwd>
<kwd lng="en"><![CDATA[individual (CSS J071813.2+505000]]></kwd>
<kwd lng="en"><![CDATA[NSVS 2459652]]></kwd>
<kwd lng="en"><![CDATA[NSVS 7178717]]></kwd>
<kwd lng="en"><![CDATA[NSVS 7377875)]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Berry]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Burnell]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[The Handbook of Astronomical Image Processing with AIP4WIN2 software]]></source>
<year>2006</year>
<publisher-name><![CDATA[Willmannn-Bell.Inc.]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Binnendijk]]></surname>
<given-names><![CDATA[L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Vistas in Astronomy]]></source>
<year>1970</year>
<volume>12</volume>
<page-range>217</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Csizmadia]]></surname>
<given-names><![CDATA[Sz.]]></given-names>
</name>
<name>
<surname><![CDATA[Klagyivik]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
</person-group>
<source><![CDATA[A&amp;A]]></source>
<year>2004</year>
<volume>426</volume>
<page-range>1001</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Flannery]]></surname>
<given-names><![CDATA[B.P.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1976</year>
<volume>205</volume>
<page-range>217</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gettel]]></surname>
<given-names><![CDATA[S.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Geske]]></surname>
<given-names><![CDATA[M.T.]]></given-names>
</name>
<name>
<surname><![CDATA[McKay]]></surname>
<given-names><![CDATA[T.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[AJ]]></source>
<year>2006</year>
<volume>131</volume>
<page-range>621</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gilliland]]></surname>
<given-names><![CDATA[R.L.]]></given-names>
</name>
<name>
<surname><![CDATA[Brown]]></surname>
<given-names><![CDATA[T.M.]]></given-names>
</name>
</person-group>
<source><![CDATA[PASP]]></source>
<year>1988</year>
<volume>100</volume>
<page-range>754</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Henden]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[The Journal of the American Association of Variable Star Observers]]></source>
<year>2016</year>
<volume>44</volume>
<page-range>84</page-range></nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Honeycutt]]></surname>
<given-names><![CDATA[R. Kent]]></given-names>
</name>
</person-group>
<source><![CDATA[PASP]]></source>
<year>1992</year>
<volume>104</volume>
<page-range>435</page-range></nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kallrath]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Milone]]></surname>
<given-names><![CDATA[E.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Terrell]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Young]]></surname>
<given-names><![CDATA[A.T.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1998</year>
<volume>508</volume>
<page-range>308</page-range></nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kipping]]></surname>
<given-names><![CDATA[D.M.]]></given-names>
</name>
</person-group>
<source><![CDATA[MNRAS]]></source>
<year>2010</year>
<volume>408</volume>
<page-range>1758</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kjurkchieva]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Popov]]></surname>
<given-names><![CDATA[V.]]></given-names>
</name>
<name>
<surname><![CDATA[Vasileva]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[Petrov]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<source><![CDATA[Serbian Astronomical Journal]]></source>
<year>2016</year>
<volume>192</volume>
<page-range>21</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Klagyivik]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Csizmadia]]></surname>
<given-names><![CDATA[Sz]]></given-names>
</name>
</person-group>
<source><![CDATA[Publications of the Astronomy Department of the Eotvos]]></source>
<year>2004</year>
<volume>14</volume>
<page-range>303</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lucy]]></surname>
<given-names><![CDATA[L.B.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1968</year>
<volume>151</volume>
<page-range>877</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lucy]]></surname>
<given-names><![CDATA[L.B.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1976</year>
<volume>205</volume>
<page-range>208</page-range></nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Martin]]></surname>
<given-names><![CDATA[H.C.]]></given-names>
</name>
<name>
<surname><![CDATA[Spruit]]></surname>
<given-names><![CDATA[H.C.]]></given-names>
</name>
<name>
<surname><![CDATA[Tata]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<source><![CDATA[A&amp;A]]></source>
<year>2011</year>
<volume>535</volume>
<page-range>A50</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Milone]]></surname>
<given-names><![CDATA[E.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Stagg]]></surname>
<given-names><![CDATA[C.R.]]></given-names>
</name>
<name>
<surname><![CDATA[Kurucz]]></surname>
<given-names><![CDATA[R.L.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJS]]></source>
<year>1992</year>
<volume>79</volume>
<page-range>123</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Prsa]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Zwitter]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>2005</year>
<volume>628</volume>
<page-range>426</page-range></nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Prsa]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>2016</year>
</nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Qian]]></surname>
<given-names><![CDATA[S.-B.]]></given-names>
</name>
</person-group>
<source><![CDATA[MNRAS]]></source>
<year>2003</year>
<volume>342</volume>
<page-range>1260</page-range></nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Robertson]]></surname>
<given-names><![CDATA[J.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Eggleton]]></surname>
<given-names><![CDATA[P.P.]]></given-names>
</name>
</person-group>
<source><![CDATA[MNRAS]]></source>
<year>1977</year>
<volume>179</volume>
<page-range>359</page-range></nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rucinski]]></surname>
<given-names><![CDATA[S.M.]]></given-names>
</name>
</person-group>
<source><![CDATA[PASP]]></source>
<year>1994</year>
<volume>106</volume>
<page-range>462</page-range></nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rucinski]]></surname>
<given-names><![CDATA[S. M.]]></given-names>
</name>
<name>
<surname><![CDATA[Milone]]></surname>
<given-names><![CDATA[E.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Mermilliod]]></surname>
<given-names><![CDATA[J.-C.]]></given-names>
</name>
</person-group>
<source><![CDATA[The origins, evolution, and destinies of binary stars in clusters]]></source>
<year>1996</year>
<page-range>270</page-range><publisher-loc><![CDATA[Calgary ]]></publisher-loc>
<publisher-name><![CDATA[University of Calgary]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B23">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rucinski]]></surname>
<given-names><![CDATA[S.M.]]></given-names>
</name>
<name>
<surname><![CDATA[Duerbeck]]></surname>
<given-names><![CDATA[H.W.]]></given-names>
</name>
</person-group>
<source><![CDATA[PASP]]></source>
<year>1997</year>
<volume>109</volume>
<page-range>1340</page-range></nlm-citation>
</ref>
<ref id="B24">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stepien]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
</person-group>
<source><![CDATA[Acta Astronomica]]></source>
<year>2006</year>
<volume>56</volume>
<page-range>199</page-range></nlm-citation>
</ref>
<ref id="B25">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Tokunaga]]></surname>
<given-names><![CDATA[A.T.]]></given-names>
</name>
<name>
<surname><![CDATA[Cox]]></surname>
<given-names><![CDATA[Arthur N.]]></given-names>
</name>
</person-group>
<source><![CDATA[Allen&#8217;s astrophysical quantities]]></source>
<year>2000</year>
<publisher-loc><![CDATA[New York ]]></publisher-loc>
<publisher-name><![CDATA[AIP Press; Springer]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B26">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Van Hamme]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
</person-group>
<source><![CDATA[AJ]]></source>
<year>1993</year>
<volume>106</volume>
<page-range>2096</page-range></nlm-citation>
</ref>
<ref id="B27">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Van Hamme]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Munari]]></surname>
<given-names><![CDATA[U.]]></given-names>
</name>
</person-group>
<source><![CDATA[ASP Conf. Ser. 298, Gaia Spectroscopy: Science and Technology]]></source>
<year>2003</year>
<page-range>323</page-range><publisher-loc><![CDATA[San Francisco ]]></publisher-loc>
<publisher-name><![CDATA[ASP]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B28">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Devinney]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1971</year>
<volume>166</volume>
<page-range>605</page-range></nlm-citation>
</ref>
<ref id="B29">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Sofia]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1976</year>
<volume>203</volume>
<page-range>182</page-range></nlm-citation>
</ref>
<ref id="B30">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1979</year>
<volume>234</volume>
<page-range>1054</page-range></nlm-citation>
</ref>
<ref id="B31">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<source><![CDATA[ApJ]]></source>
<year>1990</year>
<volume>356</volume>
<page-range>613</page-range></nlm-citation>
</ref>
<ref id="B32">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Wilson]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<source><![CDATA[ASPC]]></source>
<year>1993</year>
<volume>38</volume>
<page-range>91</page-range></nlm-citation>
</ref>
<ref id="B33">
<nlm-citation citation-type="">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zacharias]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
</person-group>
<source><![CDATA[AJ]]></source>
<year>2013</year>
<volume>145</volume>
<page-range>44</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
