The Age of the HD 15407 System and the Epoch of Final Catastrophic Mass Accretion onto Terrestrial Planets around Sun-like Stars

TL;DR

This paper studies the HD 15407 system's age and finds evidence of recent planetary collisions, indicating that terrestrial planet formation around Sun-like stars is a common, ongoing process occurring between 30 and 100 million years.

Contribution

It provides observational evidence linking dust phenomena to planetary formation stages and refines the timeline of terrestrial planet assembly around Sun-like stars.

Findings

HD 15407 system is approximately 80 Myr old.

Strong mid-infrared excess indicates recent planetary collisions.

Terrestrial planet formation around Sun-like stars occurs mainly between 30 and 100 Myr.

Abstract

From optical spectroscopic measurements we determine that the HD 15407 binary system is ~80 Myr old. The primary, HD 15407A (spectral type F5V), exhibits strong mid-infrared excess emission indicative of a recent catastrophic collision between rocky planetary embryos or planets in its inner planetary system. Synthesis of all known stars with large quantities of dust in their terrestrial planet zone indicates that for stars of roughly Solar mass this warm dust phenomenon occurs at ages between 30 and 100 Myr. In contrast, for stars of a few Solar masses, the dominant era of the final assembling of rocky planets occurs earlier, between 10 and 30 Myr age. The incidence of the warm dust phenomenon, when compared against models for the formation of rocky terrestrial-like bodies, implies that rocky planet formation in the terrestrial planet zone around Sun-like stars is common.