ExoPhot: Phot0, a plausible primeval pigment on Earth and rocky exoplanets
Authors: García de la Concepción Juan , Marcos-Arenal Pablo 
Published: March 2022

&lt;p&gt;&lt;span&gt;&lt;span&gt;Photosynthesis, the metabolic route for conversion of solar to chemical energy, could be present in any planetary system provided with the only three required ingredients: a light source, water, and carbon dioxide. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;The &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ExoPhot&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; project aims to study the relation between photosynthetic systems and exoplanet conditions around different types of stars (i.e. stellar spectral types) by focusing on two aspects: Assessing the photosynthetic fitness of a variety of &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;photopigm&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ents&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; (either real or theoretical) as a function of stellar spectral type, star-exoplanet separation, and planet atmosphere composition; and delineating a range of stellar, exoplanet and atmospheric parameters for which photosynthetic activity might be feas&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ible. In order to tackle this goals, this project is studying the evolutionary steps that led to the highly evolved chlorophylls and analogues, and assessing the feasibility or likelihood to trigger photosynthetic activity in an exoplanetary system. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;Based&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; on the Darwinian theory of common ancestors, the first (photosynthetic) organism should have had simple oligopeptides, oligonucleotides and alkyl amphiphilic hydrocarbons as primeval membranes. Therefore, it should have had simple pigments. We propose tha&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;t there could exist geochemical conditions allowing the abiotic formation of a simple pigment which might become sufficiently abundant in the environment of an exoplanet. Besides, we show that the proposed pigment could also be a precursor of the more evol&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ved pigments known today on Earth by proposing, for the first time, an abiotic chemical route leading to &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;tetrapyrroles&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; not involving pyrrole derivatives.&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;Juan Garc&amp;#237;a de la &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Concepci&amp;#243;n&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;a&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;,&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;*&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; Pablo Marcos-&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Arenal&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;a&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;,&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; Luis &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Cerd&amp;#225;n&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;b&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, Mercedes Burillo-&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Villalobos&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;c&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, Nuria Fonseca-&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Bonilla&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;a&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;,Mar&amp;#237;a&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;-&amp;#193;ngeles L&amp;#243;pez-&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Cayuela&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;d&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, Jos&amp;#233; A. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Caballero&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;e&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, and &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Felipe G&amp;#243;mez &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;G&amp;#243;mez&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;a&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;a&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Centro&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; de Astrobiolog&amp;#237;a (CSIC-INTA), Ctra. de &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Ajalvir&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; km. 4, Torrej&amp;#243;n de &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Ardoz&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, 28850 Madrid, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Spain&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;;&lt;/span&gt;&lt;/span&gt; &lt;span&gt;&lt;span&gt;b&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Instituto&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; de Ciencia Molecular (&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ICMoL&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;), Universidad de Valencia, 46071 Valencia, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Spain&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;.;&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;c&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Instituto&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; Nacional de T&amp;#233;cnica Aeroespacial,&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; 28850 Torrej&amp;#243;n de &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Ardoz&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, Madrid, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Spain&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;.;&lt;/span&gt;&lt;/span&gt; &lt;span&gt;&lt;span&gt;d&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;&amp;#193;rea&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; de Investigaci&amp;#243;n e Instrumentaci&amp;#243;n &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Atmosf&amp;#233;rica,Instituto&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; Nacional de T&amp;#233;cnica Aeroespacial, 28850 Torrej&amp;#243;n de &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Ardoz&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, Madrid, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Spain&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;.;&lt;/span&gt;&lt;/span&gt; &lt;span&gt;&lt;span&gt;e&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Centro&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; de Astrobiolog&amp;#237;a (CSIC-INTA), ESAC, camino bajo del castillo, 28691 &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Villanueva de la Ca&amp;#241;ada, Madrid, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Spain&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;