The GAPS programme at TNG

XLVIII. The unusual formation history of V1298 Tau^★

¹ INAF – Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy
e-mail: diego.turrini@inaf.it
² ICSC – National Research Centre for High Performance Computing, Big Data and Quantum Computing, Via Magnanelli 2, 40033 Casalecchio di Reno, Italy
³ INAF – Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, 00133 Roma, Italy
⁴ Dipartimento di Fisica e Astronomia – Università di Padova, Via Marzolo 8, 35121 Padova, Italy
⁵ INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122, Padova, Italy
⁶ INAF – Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143, Trieste, Italy
⁷ INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento, 1, 90134, Palermo, Italy
⁸ Space Science Data Center - ASI, Via del Politecnico snc, 00133 Roma, Italy
⁹ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
¹⁰ Universidad de La Laguna, Dept. Astrofísica, 38206 La Laguna, Tenerife, Spain
¹¹ INAF – Osservatorio Astronomico di Roma, Via Frascati 33, 00040, Monte Porzio Catone, Italy
¹² School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
¹³ SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK
¹⁴ INAF – Osservatorio Astronomico di Brera, Via E. Bianchi 46, 23087, Merate, Italy
¹⁵ Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Sta. Ma. Tonantzintla, Puebla, Mexico
¹⁶ Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France
¹⁷ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
¹⁸ Geneva Observatory, University of Geneva, Chemin Pegasi 51, 1290 Versoix, Switzerland
¹⁹ Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
²⁰ CRAL, UMR 5574, CNRS, Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d’Italie, 69364 Lyon Cedex 07, France
²¹ INAF – Osservatorio Astrofisico di Catania, Via Santa Sofia 78, 95123 Catania, Italy
²² Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
²³ INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, 09047 Selargius, Italy
²⁴ Department of Physics, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133, Roma, Italy
²⁵ Max Planck Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany
²⁶ Aix-Marseille Univ., CNRS, CNES, LAM, Marseille, France

Received: 15 August 2022
Accepted: 4 July 2023

Abstract

Context. Observational data from space- and ground-based campaigns have revealed that the 10-30 Ma old V1298Tau star hosts a compact and massive system of four planets. Mass estimates are available for the two outer giant planets and point to unexpectedly high densities for their young ages.

Aims. We investigate the formation of these two outermost giant planets, V1298 Tau b and e, and the present dynamical state of V1298 Tau’s global architecture in order to shed light on the history of this young and peculiar extrasolar system.

Methods. We performed detailed N-body simulations to explore the link between the densities of V1298 Tau b and e and their migration and accretion of planetesimals within the native circumstellar disk. We combined N-body simulations and the normalized angular momentum deficit (NAMD) analysis of the architecture to characterize V1298 Tau’s dynamical state and connect it to the formation history of the system. We searched for outer planetary companions to constrain V1298 Tau’s planetary architecture and the extension of its primordial circumstellar disk.

Results. The high densities of V1298 Tau b and e suggest they formed at quite a distance from their host star, likely beyond the CO₂ snowline. The higher nominal density of V1298 Tau e suggests it formed farther out than V1298 Tau b. The current architecture of V1298 Tau is not characterized by resonant chains. Planet-planet scattering with an outer giant planet is the most likely cause for the lack of a resonant chain between V1298 Tau’s planets, but currently our search for outer companions using SPHERE and Gaia observations can exclude only the presence of planets more massive than 2 M_J.

Conclusions. The most plausible scenario for V1298 Tau’s formation is that the system formed by convergent migration and resonant trapping of planets born in a compact and plausibly massive disk. In the wake of their migration, V1298 Tau b and e would have left a dynamically excited protoplanetary disk, naturally creating the conditions for the later breaking of the resonant chain by planet-planet scattering.