<?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>S0185-11012013000100012</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[New orbits for Comets C/1960 M1 (Humason), C/1980 E1 (Bowell), and musings on extrasolar comets]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Branham]]></surname>
<given-names><![CDATA[Richard L.]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales  ]]></institution>
<addr-line><![CDATA[Mendoza ]]></addr-line>
<country>Argentina</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>04</month>
<year>2013</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>04</month>
<year>2013</year>
</pub-date>
<volume>49</volume>
<numero>1</numero>
<fpage>111</fpage>
<lpage>116</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012013000100012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012013000100012&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012013000100012&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Se calculan órbitas nuevas para los cometas Humason (C/1960 M1) y Bowell (C/1980 El1. La órbita de Humason se basa en 34 observaciones hechas durante 348 días y para Bowell en 203 observaciones hechas durante ocho años. Integraciones hacia atrás indican que ambos cometas tenían órbitas originalmente muy elípticas, que fueron cambiadas a hipérbolas por la adición de energía desde el Sistema Solar. Puesto que sus distancias del perihelio son mayores de 3 AU, la posibilidad de fuerzas no gravitatorias es remota. Para el cometa Secchi (C/1853 E1), sin embargo, la órbita es hiperbólica a una distancia de más de 100000 AU del Sol y sin evidencia alguna de fuerzas no gravitatorias. Si la órbita permanece hipérbolica a esa distancia, quizás su origen sea fuera de la nube de Oort.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[New orbits are calculated for Comets Humason (C/1960 M1) and Bowell (C/1980 E1). Humason's orbit is based on 34 observation made over 348 days and Bowell's on 203 observations made over nearly eight years. Both comets have hyperbolic orbits. Backwards integrations indicate that both comets had originally highly elliptical orbits which changed to hyperbolas by the injection oí energy from the Solar System. Given that both of their perihelions are more than 3 AU from the Sun, the possibility of nongravitational forces is remote. For Comet Secchi (C/1853 E1), however, the orbit is hyperbolic at more than 100000 AU from the Sun and with no indication of nongravitational forces. If the orbit is a hyperbola at that distance, could the comet's origin not be from beyond the Oort cloud?]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[comets]]></kwd>
<kwd lng="en"><![CDATA[methods]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ <p align="justify"><font face="verdana" size="4">Articles</font></p>     <p align="justify"><font face="verdana" size="4">&nbsp;</font></p>     <p align="center"><font face="verdana" size="4"><b>New orbits for Comets C/1960 M1 (Humason), C/1980 E1 (Bowell), and musings on extrasolar comets</b></font></p>     <p align="center"><font face="verdana" size="2">&nbsp;</font></p>     <p align="center"><font face="verdana" size="2"><b>Richard L. Branham, Jr.</b></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><i>Instituto Argentino de Nivolog&iacute;a, Glaciolog&iacute;a y Ciencias Ambientales, C.C. 330, Mendoza, Argentina.</i> (<a href="mailto:rlb@lanet.com.ar">rlb@lanet.com.ar</a>).</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2">Received 2012 September 5.    <br> Accepted 2013 January 21.</font></p>     ]]></body>
<body><![CDATA[<p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>RESUMEN</b></font></p>     <p align="justify"><font face="verdana" size="2">Se calculan &oacute;rbitas nuevas para los cometas Humason (C/1960 M1) y Bowell (C/1980 El1. La &oacute;rbita de Humason se basa en 34 observaciones hechas durante 348 d&iacute;as y para Bowell en 203 observaciones hechas durante ocho a&ntilde;os. Integraciones hacia atr&aacute;s indican que ambos cometas ten&iacute;an &oacute;rbitas originalmente muy el&iacute;pticas, que fueron cambiadas a hip&eacute;rbolas por la adici&oacute;n de energ&iacute;a desde el Sistema Solar. Puesto que sus distancias del perihelio son mayores de 3 AU, la posibilidad de fuerzas no gravitatorias es remota. Para el cometa Secchi (C/1853 E1), sin embargo, la &oacute;rbita es hiperb&oacute;lica a una distancia de m&aacute;s de 100000 AU del Sol y sin evidencia alguna de fuerzas no gravitatorias. Si la &oacute;rbita permanece hip&eacute;rbolica a esa distancia, quiz&aacute;s su origen sea fuera de la nube de Oort.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><b>ABSTRACT</b></font></p>     <p align="justify"><font face="verdana" size="2">New orbits are calculated for Comets Humason (C/1960 M1) and Bowell (C/1980 E1). Humason's orbit is based on 34 observation made over 348 days and Bowell's on 203 observations made over nearly eight years. Both comets have hyperbolic orbits. Backwards integrations indicate that both comets had originally highly elliptical orbits which changed to hyperbolas by the injection o&iacute; energy from the Solar System. Given that both of their perihelions are more than 3 AU from the Sun, the possibility of nongravitational forces is remote. For Comet Secchi (C/1853 E1), however, the orbit is hyperbolic at more than 100000 AU from the Sun and with no indication of nongravitational forces. If the orbit is a hyperbola at that distance, could the comet's origin not be from beyond the Oort cloud?</font></p>     <p align="justify"><font face="verdana" size="2"><b>Key Words: </b>comets: individual (Humason, Bowell) &#151; methods: numerical.</font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     <p align="justify"><font face="verdana" size="2"><a href="/pdf/rmaa/v49n1/v49n1a12.pdf" target="_blank">DESCARGAR ART&Iacute;CULO EN FORMATO PDF</a></font></p>     <p align="justify"><font face="verdana" size="2">&nbsp;</font></p>     ]]></body>
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