{
  "abstract": "The K2-3 system is one of the most unique planetary systems as it features three transiting sub-Neptunes in decreasing order of radii, spanning the radius valley. In addition to that, the two outer planets are temperate in nature making this system a perfect laboratory for investigating the nature and formation of small potentially habitable worlds. We present new radial velocity data obtained during the ESPRESSO-GTO programme to add to the archival HARPS, HARPS-N and HIRES data for a total time span of 8 years. This combined dataset significantly improves the masses of the K2-3 planets. We analyse the spectroscopic data with the line-by-line algorithm. We coupled this timeseries with a multi-dimensional Gaussian process framework to disentangle the 40.5-days stellar rotation from the Keplerian signals. We tested models using two activity indicators to ensure the retrieved semi-amplitudes of the planets are not biased by the choice of activity indicator. The multi-dimensional Gaussian process framework, with either activity indicator, yields the following masses: Mb=6.61+/-0.47Me; Mc=2.23+/-0.68Me; Md=2.12+/-1.27Me. Compared to previous works, our detection significance of K2-3b has increased by a factor of two, the mass of K2-3c has slightly decreased and we now have a marginal detection for K2-3d. The positions of the planets in the mass-radius diagram suggest either a H/He-rich or volatile-rich composition for both K2-3b and c, while the nature of K2-3d is ambiguous. A forward atmospheric model suggests that a single visit with JWST can distinguish between a H/He-rich atmosphere from a water-world scenario. This dataset exemplifies the capability of ESPRESSO to detect sub-metre-per-second radial velocity signals for the detection of temperate exoplanets.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.17792",
  "author_total": 27,
  "authors": [
    {
      "name": "Avidaan Srivastava"
    },
    {
      "name": "Emma Pimentel"
    },
    {
      "name": "Amélie Gressier"
    },
    {
      "name": "René Doyon"
    },
    {
      "name": "Melissa J. Hobson"
    },
    {
      "name": "Alessandro Sozzetti"
    },
    {
      "name": "Mario Damasso"
    },
    {
      "name": "Yann Alibert"
    },
    {
      "name": "Susana C. C. Barros"
    },
    {
      "name": "François Bouchy"
    },
    {
      "name": "Amadeo Castro-González"
    },
    {
      "name": "Olivier D. S. Demangeon"
    },
    {
      "name": "Xavier Dumusque"
    },
    {
      "name": "Jonay I. González Hernández"
    },
    {
      "name": "Baptiste Lavie"
    },
    {
      "name": "Jorge Lillo-Box"
    },
    {
      "name": "Christophe Lovis"
    },
    {
      "name": "Giuseppina Micela"
    },
    {
      "name": "Enric Palle"
    },
    {
      "name": "Francesco Pepe"
    },
    {
      "name": "Rafael Rebolo"
    },
    {
      "name": "José Rodrigues"
    },
    {
      "name": "Nuno C. Santos"
    },
    {
      "name": "Sérgio G. Sousa"
    },
    {
      "name": "Alejandro Suárez Mascareño"
    },
    {
      "name": "Stéphane Udry"
    },
    {
      "name": "María R. Zapatero-Osorio"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/14edpymmh37km.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.17792",
  "fulltext_url": null,
  "id": "14edpymmh37km",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.17792",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.EP"
    ],
    [
      "openalex",
      "3103|Stellar, planetary, and galactic studies"
    ]
  ],
  "openalex": "W7213516366",
  "pdf_url": "https://arxiv.org/pdf/2609.17792",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/14edpymmh37km.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "2609.17792",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.17792"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "Uncovering temperate worlds: an updated look at the K2-3 system with ESPRESSO",
  "title_text": "Uncovering temperate worlds: an updated look at the K2-3 system with ESPRESSO",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/14edpymmh37km",
  "venue": "arXiv",
  "versions": []
}