The NCORES Program: Precise Planetary Masses, Null Results, and Insight Into The Planet Mass Distribution Near The Radius Gap

NCORES was a large observing program on the ESO HARPS spectrograph, dedicated to measuring the masses of Neptune-like and smaller transiting planets discovered by the TESS satellite using the radial velocity technique.

This paper presents an overview of the programme, its scientific goals and published results, covering 35 planets in 18 planetary systems. We present spectrally derived stellar characterisation and mass constraints for five additional TOIs where radial velocity observations found only marginally significant signals (TOI-510.01, M_p=1.08+0.58−0.55M_⊕), or found no signal (TOIs 271.01, 641.01, 697.01 and 745.01).

A newly detected non-transiting radial velocity candidate is presented orbiting TOI-510 on a 10.0d orbit, with a minimum mass of 4.82+1.29−1.26M_⊕, although uncertainties on the system architecture and true orbital period remain. Combining the NCORES sample with archival known planets we investigate the distribution of planet masses and compositions around and below the radius gap, finding that the population of planets below the gap is consistent with a rocky composition and ranges up to a sharp cut-off at 10M_⊕.

We compare the observed distribution to models of pebble- and planetesimal-driven formation and evolution, finding good broad agreement with both models while highlighting interesting areas of potential discrepancy. Increased numbers of precisely measured planet masses in this parameter space are required to distinguish between pebble and planetesimal accretion.

David J. Armstrong, Ares Osborn, Remo Burn, Julia Venturini, Vardan Adibekyan, Andrea Bonfanti, Jennifer A. Burt, Karen A. Collins, Elisa Delgado Mena, Andreas Hadjigeorghiou, Steve Howell, Sam Quinn, Sergio G. Sousa, Marcelo Aron F. Keniger, David Barrado, Susana C. C. Barros, Daniel Bayliss, François Bouchy, Amadeo Castro-González, Kevin I. Collins, Denis M. Conti, Ian M. Crossfield, Rodrigo Diaz, Xavier Dumusque, Fabo Feng, Kathryn V. Lester, Jorge Lillo- Box, Rachel A. Matson, Elisabeth C. Matthews, Christoph Mordasini, Felipe Murgas, Hugh P. Osborn, Enric Palle, Nuno Santos, Richard P. Schwarz, Tomás Azevedo Silva, Keivan Stassun, Paul Strøm, Thiam-Guan Tan, Johanna Teske, Gavin Wang, Peter J. Wheatley

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2501.14355 [astro-ph.EP] (or arXiv:2501.14355v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2501.14355
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From: David Armstrong
[v1] Fri, 24 Jan 2025 09:42:08 UTC (3,544 KB)
https://arxiv.org/abs/2501.14355
Astrobiology