{
  "abstract": "Close-in planets orbiting core-helium-burning red-clump giants directly challenge tidal-engulfment theory, which predicts that planets within about 1 au of Sun-like stars should be engulfed during red-giant-branch (RGB) expansion. The existence of such survivors would imply missing physical processes in the late stages of stellar and planetary evolution. Yet only one such “forbidden” planet had been identified to date. Here we report three systems—24 Boo b, HD 12648 b, and TYC 4282-605-1 b—whose host stars are confirmed red-clump giants through asteroseismology, showing that each has already undergone dramatic expansion and contraction following helium ignition. Their planets now reside at orbital separations smaller than the maximum stellar radii attained during the RGB phase, implying that they should not have survived. Among them, 24 Boo b orbits at only 0.183 au with a 30-d period, making it the closest planet known around a red-clump giant. These findings demonstrate that this paradox is not an isolated anomaly but signals the emergence of a class of evolved planetary systems. Their survival defies current models of stellar–planetary coevolution and points to unexplored physics shaping planetary architectures around post-RGB stars.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Astronomy, School of Physics and Astronomy, Yunnan University, Kunming 650091, People’s Republic of China",
    "Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011, People’s Republic of China",
    "University of Chinese Academy of Sciences, Beijing 101408, People’s Republic of China",
    "Yunnan Training Center for Ethnic Leadership, Yunnan Minzu University, Kunming 650504, People’s Republic of China"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Wen-Xu Lin",
      "orcid": "0000-0002-8276-5634"
    },
    {
      "affs": [
        0
      ],
      "name": "Sheng-Bang Qian",
      "orcid": "0009-0009-7581-9209"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Qi-Bin Sun",
      "orcid": "0000-0003-0516-404X"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Li-Ying Zhu",
      "orcid": "0000-0002-0796-7009"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Wen-Ping Liao"
    },
    {
      "affs": [
        3
      ],
      "name": "Ting Li"
    },
    {
      "affs": [
        0
      ],
      "name": "Fu-Xing Li",
      "orcid": "0000-0002-0285-6051"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Xiang-Dong Shi",
      "orcid": "0000-0002-5038-5952"
    },
    {
      "affs": [
        0
      ],
      "name": "Tao Wang"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Er-Gang Zhao"
    },
    {
      "affs": [
        0
      ],
      "name": "Hui-Ting Zhang"
    },
    {
      "affs": [
        0
      ],
      "name": "Ping Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0q9pmx3xhj8vx.bib",
  "cited_by": 0,
  "doi": "10.1073/pnas.2603847123",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13715826/",
  "id": "0q9pmx3xhj8vx",
  "issns": [
    "0027-8424",
    "1091-6490"
  ],
  "landing_url": "https://doi.org/10.1073/pnas.2603847123",
  "language": "en",
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "406"
    ],
    [
      "heading",
      "Astronomy"
    ],
    [
      "heading",
      "Physical Sciences"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7223203452",
  "pdf_url": null,
  "pmcid": "PMC13715826",
  "pmid": "42911866",
  "published": "2026-10-22",
  "publisher": "National Academy of Sciences",
  "ris": "https://research.draconitic.com/paper/0q9pmx3xhj8vx.ris",
  "sources": [
    {
      "first_seen": "2026-11-01T12:23:01Z",
      "native_id": "PMC13715826",
      "source": "pmc",
      "url": "https://doi.org/10.1073/pnas.2603847123"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "The survival paradox of close-in planets orbiting red-clump giants",
  "title_text": "The survival paradox of close-in planets orbiting red-clump giants",
  "type": "peer-reviewed",
  "updated_at": "2026-11-01T12:23:01Z",
  "url": "https://research.draconitic.com/paper/0q9pmx3xhj8vx",
  "venue": "Proceedings of the National Academy of Sciences of the United States of America",
  "versions": [
    {
      "doi": "10.48550/arxiv.2611.04544",
      "pid": "av94t3kcrsv4k",
      "relation": "preprint",
      "title": "The Survival Paradox of Close-In Planets Orbiting Red Clump Giants",
      "venue": "arXiv"
    }
  ]
}