[et_pb_section fb_built=”1″ admin_label=”Section” _builder_version=”4.16″ _module_preset=”default” background_image=”https:\/\/www.ieec.cat\/wp-content\/uploads\/2022\/02\/slider-comunicacio.jpg” max_height=”130px” custom_padding=”0px||0px||false|false” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][\/et_pb_section][et_pb_section fb_built=”1″ admin_label=”Section” _builder_version=”4.16″ _module_preset=”default” custom_padding=”24px||11px|||” da_disable_devices=”off|off|off” global_colors_info=”{}” da_is_popup=”off” da_exit_intent=”off” da_has_close=”on” da_alt_close=”off” da_dark_close=”off” da_not_modal=”on” da_is_singular=”off” da_with_loader=”off” da_has_shadow=”on”][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_padding=”||||false|false” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Unitats de recerca” module_class=”ieec-orgs” _builder_version=”4.27.4″ _dynamic_attributes=”content” _module_preset=”default” text_font=”|700||on|||||” text_font_size=”16px” header_font=”|700|||||||” custom_margin=”||10px||false|false” header_font_size_tablet=”28px” header_font_size_phone=”26px” header_font_size_last_edited=”on|phone” global_colors_info=”{}”]@ET-DC@eyJkeW5hbWljIjp0cnVlLCJjb250ZW50IjoiY3VzdG9tX21ldGFfb3JnYW5pemFjaW9uZXMiLCJzZXR0aW5ncyI6eyJiZWZvcmUiOiIiLCJhZnRlciI6IiIsImVuYWJsZV9odG1sIjoib2ZmIn19@[\/et_pb_text][et_pb_post_title author=”off” categories=”off” comments=”off” featured_image=”off” admin_label=”T\u00edtol i data” module_class=”ieec-title” _builder_version=”4.27.5″ _module_preset=”default” title_font=”Cairo|300|||||||” title_font_size=”40px” meta_font=”||on||||||” meta_font_size=”16px” title_font_size_tablet=”35px” title_font_size_phone=”30px” title_font_size_last_edited=”on|desktop” global_colors_info=”{}”][\/et_pb_post_title][et_pb_text admin_label=”Subt\u00edtols” module_class=”ieec-summary” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Source Sans Pro||on||||||” text_font_size=”24px” text_line_height=”1.1em” hover_enabled=”0″ text_font_size_tablet=”22px” text_font_size_phone=”20px” text_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n
[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_post_title title=”off” meta=”off” module_class=”ieec-img-container” _builder_version=”4.27.2″ _module_preset=”default” custom_margin=”||0px||false|false” border_width_top=”10px” border_color_top=”#406fda” global_colors_info=”{}”][\/et_pb_post_title][et_pb_text module_class=”ieec-img-footer” _builder_version=”4.27.6″ _module_preset=”default” text_font=”||||||||” text_font_size=”15px” text_line_height=”1.1em” background_color=”rgba(64,111,218,0.15)” custom_margin=”0px||||false|false” custom_padding=”30px|20px|30px|20px|true|true” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n
Artist impression of the planetary system around the star LHS 1903 (distances and sizes of the planets are not to scale). ESA<\/strong><\/p>\n [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n An international scientific team has discovered an unusual feature in the planetary system around the star called LHS 1903. <\/span>The order of its planets challenges current planet formation theories<\/b>. Scientists believe that the most distant outer planet in the system might be rocky\u2014instead of gaseous, as would normally be expected\u2014and was formed later and in a different environment than the other planets around the star. The team, including researchers from the <\/span>Institute of Space Studies of Catalonia<\/span><\/a> (IEEC) at the <\/span>Institute of Space Sciences<\/span><\/a> (ICE-CSIC), has detailed these surprising results in an article published yesterday in the journal <\/span>Science<\/span><\/i>.<\/span><\/p>\n The eight planets of our Solar System\u2014Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune\u2014can be sorted into two different types: rocky and gaseous. The inner planets that are closest to the Sun\u2014Mercury to Mars\u2014are rocky, and the outer planets\u2014Jupiter to Neptune\u2014are gaseous.\u00a0<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n \u201cThis general pattern, that planetary systems form with rocky planets closer to their star, followed by gaseous planets as the outer bodies, has been commonly observed across the Universe. It is what our current planet formation theories predict and what observations have widely confirmed to be true,\u201d explains Ignasi Ribas, IEEC researcher at the ICE-CSIC and one of the authors of the study.<\/span><\/p>\n That was until scientists took a closer look at the planetary system around the star LHS 1903 with the CHaracterising ExOPlanet Satellite (<\/span>Cheops<\/span><\/a>) of the <\/span>European Space Agency<\/span><\/a> (ESA). What they have just discovered might flip our understanding of how planets form upside down.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text module_class=”section-title” _builder_version=”4.27.6″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” hover_enabled=”0″ header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n LHS 1903 is a small red M-dwarf star that is cooler and shines less brightly than our Sun. Thomas Wilson from the <\/span>University of Warwick<\/span><\/a> in the UK and his international team combined the efforts of various telescopes in space and on Earth to classify three planets that they had spotted orbiting LHS 1903. They were able to conclude that the innermost planet seemed to be rocky, and the two that followed it gaseous.<\/span><\/p>\n So far, so normal. It wasn\u2019t until Wilson and his colleagues were analysing observations made by ESA\u2019s Cheops, that they discovered something strange: <\/span>the data showed a small fourth planet, furthest from LHS 1903<\/b>. And upon closer inspection, the scientists were surprised to discover that this planet seems to be rocky.\u00a0<\/span><\/p>\n \u201cThat makes this a system with a planet order of rocky-gaseous-gaseous-and then rocky again. Rocky planets don\u2019t usually form so far away from their home star,\u201d says Wilson.<\/span><\/p>\n Current planet formation theories predict that the inner planets in a system are small and rocky, because <\/span>close to the star the radiation is so powerful that it sweeps away most of the gas around the planets\u2019 rocky core<\/b>. Further away from the star, in the outer part of a planetary system, the conditions are cool enough for a thick atmosphere to gather into a gaseous planet.\u00a0<\/span><\/p>\n ESA\u2019s Cheops project scientist Maximilian G\u00fcnther is enthusiastic: \u201cMuch about how planets form and evolve is still a mystery. Finding clues like this one for solving this puzzle is precisely what Cheops set out to do.\u201d<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text module_class=”section-title” _builder_version=”4.27.6″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” hover_enabled=”0″ header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Scientists are not quick to say that an established theory needs to be reconsidered, based on a single contradictory observation. So, Wilson and his colleagues <\/span>set out to explore various explanations for why this strange rocky planet breaks the familiar pattern<\/b>.<\/span><\/p>\n Was the planet, for example, at some point in its past hit by a giant asteroid, comet, or another big object, that blew away its atmosphere? Or had the planets around LHS 1903 swapped places at some point during their evolution? After testing these scenarios through simulations and calculations of the planets\u2019 orbital times, the team of scientists ruled them out.\u00a0<\/span><\/p>\n Instead, their investigation led them to a more intriguing explanation: <\/span>the planets may have formed one after the other, instead of at the same time<\/b>. According to our current understanding, planets form from discs of gas and dust (protoplanetary discs) by clumping into planetary embryos at roughly the same time. These clumps then evolve into planets of different sizes and compositions over millions of years.\u00a0<\/span><\/p>\n In contrast, here the researchers discovered a planetary system where the star might have given birth to its four planets one after the other, instead of bearing quadruplets at once. This idea, known as<\/span>\u00a0inside-out planet formation, was proposed by scientists as a theory about a decade ago<\/b>, but until now, never has the evidence been so strong.\u00a0<\/span><\/p>\n [\/et_pb_text][et_pb_image src=”https:\/\/www.ieec.cat\/wp-content\/uploads\/2026\/02\/Cheops_open_questions_How_do_planets_form.jpg” title_text=”Cheops_open_questions_How_do_planets_form” _builder_version=”4.27.5″ _module_preset=”default” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text module_class=”section-title” _builder_version=”4.27.6″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” hover_enabled=”0″ header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” link_font=”|700|||on||||” hover_enabled=”0″ locked=”off” global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n This conclusion comes with an additional catch: Much like how our younger siblings are growing up in a world that is different from the one of our childhoods, <\/span>this small rocky planet seems to have evolved and formed in a very different environment than its older sibling-planets<\/b>.\u00a0<\/span><\/p>\n \u201cBy the time this outer planet formed, the system may have already run out of gas, which is considered vital for planet formation. Yet here is a small, rocky world, defying expectations. It seems that we have found first evidence for a planet which formed in what we call a gas-depleted environment,\u201d says Wilson.\u00a0<\/span><\/p>\n The small rocky world is either <\/span>an odd outlier, or the first evidence for a trend we hadn\u2019t known about yet<\/b>. Either way, its discovery begs for an explanation that lies beyond our usual planet formation theories.<\/span><\/p>\n \u201cHistorically, our planet formation theories are based on what we see and know about our Solar System,\u201d Isabel Rebollido who is currently a Research Fellow at ESA points out. \u201cAs we are seeing more and more different exoplanet systems, we are starting to revisit these theories.\u201d<\/span><\/p>\n As our instruments improve, we continue to discover more and more \u2018weird\u2019 planetary systems in the vastness of space. They force us to question our understanding and make us reconsider established theories of planet formation. Ultimately, these discoveries are helping us learn about how our Solar System fits into the big family of diverse planetary systems. Maybe, after all, the weird one is our Solar System.<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”30px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”M\u00e9s informaci\u00f3” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n More information<\/p>\n [\/et_pb_text][et_pb_text module_class=”ieec-sub-text” _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on||||” custom_margin=”20px||||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n This research is presented in a paper entitled \u201c<\/span>Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903<\/span><\/a>\u201d, by <\/span>T.G. Wilson<\/span> et al.<\/span><\/i>, to appear in the journal Science on 12 February 2026. <\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”Enlla\u00e7os” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Links<\/p>\n [\/et_pb_text][et_pb_text module_class=”ieec-sub-text” _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on|||#1a1140|” link_text_color=”#1a1140″ link_line_height=”1.4em” custom_margin=”20px||||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.16″ _module_preset=”default” custom_margin=”||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_divider color=”#406fda” _builder_version=”4.16″ _module_preset=”default” custom_margin=”||10px||false|false” global_colors_info=”{}”][\/et_pb_divider][et_pb_text admin_label=”Contactes” module_class=”ieec-sub-title” _builder_version=”4.27.6″ _module_preset=”default” text_font=”Cairo|700|||||||” text_text_color=”#406fda” text_font_size=”20px” custom_margin=”||10px||false|false” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Contacts<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”2_5,3_5″ admin_label=”Row” _builder_version=”4.16″ _module_preset=”default” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”2_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||20px|false|false” border_width_left=”1px” border_color_left=”#406fda” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.16″ _module_preset=”default” text_font_size=”16px” text_line_height=”1.1em” link_font=”|700|||on|||#1a1140|” link_text_color=”#1a1140″ link_line_height=”1.4em” header_4_font=”|700|||||||” header_4_text_color=”#1a1140″ custom_margin=”||||false|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n Castelldefels, Barcelona [\/et_pb_text][\/et_pb_column][et_pb_column type=”3_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||20px|false|false” border_width_left=”1px” border_color_left=”#406fda” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.27.6″ _module_preset=”default” text_font_size=”16px” text_line_height=”1em” link_font=”|700|||on||||” link_text_color=”#1a1140″ header_4_font=”|700|||||||” header_4_text_color=”#1a1140″ hover_enabled=”0″ global_colors_info=”{}” theme_builder_area=”post_content” sticky_enabled=”0″]<\/p>\n Institute of Space Studies of Catalonia (IEEC) [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row module_id=”ieec-about” module_class=”about-ieec” _builder_version=”4.27.4″ _module_preset=”default” background_color=”rgba(64,111,218,0.15)” global_module=”17324″ global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”20px|50px|20px|50px|true|true” global_colors_info=”{}”][et_pb_text admin_label=”Sobre l’IEEC” _builder_version=”4.16″ _module_preset=”default” header_2_font=”|700|||||||” header_2_font_size=”25px” custom_margin=”||10px||false|false” header_2_font_size_tablet=”23px” header_2_font_size_phone=”23px” header_2_font_size_last_edited=”on|phone” locked=”off” global_colors_info=”{}”]<\/p>\n [\/et_pb_text][et_pb_text admin_label=”Text” _builder_version=”4.16″ _module_preset=”default” text_font=”||on||||||” link_font=”|700|||on||||” locked=”off” global_colors_info=”{}”]<\/p>\n The Institute of Space Studies of Catalonia (IEEC \u2014 Institut d\u2019Estudis Espacials de Catalunya) promotes and coordinates space research and technology development in Catalonia for the benefit of society. IEEC fosters collaborations both locally and worldwide and is an efficient agent of knowledge, innovation and technology transfer. As a result of more than 25 years of high-quality research, done in collaboration with major international organisations, IEEC ranks among the best international research centres, focusing on areas such as: astrophysics, cosmology, planetary science, and Earth Observation. IEEC\u2019s engineering division develops instrumentation for ground- and space-based projects, and has extensive experience in working with private or public organisations from the aerospace and other innovation sectors.<\/p>\n The IEEC is a non-profit public sector foundation that was established in February 1996. It has a Board of Trustees composed of the Generalitat de Catalunya, Universitat de Barcelona (UB), Universitat Aut\u00f2noma de Barcelona (UAB), Universitat Polit\u00e8cnica de Catalunya \u00b7 BarcelonaTech (UPC), and the Spanish Research Council (CSIC). The IEEC is also a CERCA centre.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":" A scientific team with the participation of the IEEC has discovered that the planets around the star LHS 1903 have an unusual order. The findings have been published in Science.<\/p>\n","protected":false},"author":5,"featured_media":42887,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"2880","footnotes":""},"categories":[111,74,98,31],"tags":[],"class_list":["post-42886","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-highlighted-news-small","category-news","category-science","category-uncategorized"],"yoast_head":"\nThe four planets of LHS 1903<\/h2>\n
A planetary enigma<\/h2>\n
A late bloomer defying expectations<\/h2>\n
\n
IEEC Communication Office<\/h4>\n
E-mail: comunicacio@ieec.cat<\/a><\/p>\nLead Researcher at the IEEC<\/h4>\n
Ignasi Ribas<\/h4>\n
Institute of Space Sciences (ICE-CSIC)
E-mail: iribas@ieec.cat<\/a>, iribas@ice.csic.es<\/a><\/p>\nAbout the IEEC<\/h2>\n