Carving the edges of the rocky planet population
File(s)
Published version
Author(s)
Lee, Eve J
Owen, James E
Type
Journal Article
Abstract
Short-period planets provide ideal laboratories for testing star–planet interaction. Planets that are smaller than ∼2 R⊕ are considered to be largely rocky, either having been stripped of or never having acquired the gaseous envelope. Zooming in on this short-period rocky planet population, clear edges appear in the mass–period and radius–period space. Over ∼0.2–20 days and 0.09–1.42 M⊙, the maximum mass of the rocky planets stays below ∼10 M⊕ with a hint of decrease toward ≲1 day, ≳4 days, and ≲0.45 M⊙. In radius–period space, there is a relative deficit of ≲2 R⊕ planets inside ∼1 day. We demonstrate how the edges in the mass–period space can be explained by a combination of tidal decay and photoevaporation, whereas the rocky planet desert in the radius–period space is a signature of magnetic drag on the planet as it orbits within the stellar magnetic field. Currently observed catastrophically evaporating planets may have started their death spiral from ∼1 day with planets of mass up to ∼0.3 M⊕ under the magnetic drag. More discoveries and characterization of small planets around mid- to late M and A stars would be welcome to better constrain the stellar parameters critical in shaping the edges of rocky planet population, including their UV radiation history, tidal effects, and magnetic properties.
Date Issued
2025-02-20
Date Acceptance
2025-01-27
Citation
Letters of the Astrophysical Journal, 2025, 980 (2)
ISSN
2041-8205
Publisher
IOP Publishing
Journal / Book Title
Letters of the Astrophysical Journal
Volume
980
Issue
2
Copyright Statement
© 2025. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
License URL
Identifier
10.3847/2041-8213/adafa3
Publication Status
Published
Article Number
L40
Date Publish Online
2025-02-18