Searching for the nature of stars with debris disks and planets^★

¹ Observatório Nacional, Rua General José Cristino 77, 28921-400 São Cristovão, Rio de Janeiro, RJ, Brazil
e-mail: ramirodelareza@yahoo.com
² Observatorio Astronómico de Córdoba, Universidad Nacional de Córdoba, Laprida 854, 5000 Córdoba, Argentina
e-mail: carolina.chavero@unc.edu.ar
³ Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290, Ciudad Autónoma de Buenos Aires, Argentina
⁴ Departamento de Física de la Tierra y Astrofísica, UCM, and IPARCOS, Facultad de Ciencias Físicas, Plaza Ciencias, 1, Madrid 28040, Spain
⁵ Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 221 00 Lund, Sweden
⁶ Ateneo de Almagro, Sección de Ciencia y Tecnología, 13270 Almagro, Spain
⁷ Centro de Astrobiología (CAB), CSIC-INTA, Camino Bajo del Castillo s/n, campus ESAC, 28692, Villanueva de la Cañada, Madrid, Spain

Received: 14 October 2022
Accepted: 16 January 2023

Abstract

The nature of the few known solar-mass stars simultaneously containing debris disks and planets remains an open question. A number of works have shown that this property appears to be independent of planetary masses as well as of stellar age, but possible correlations with stellar kinematics and metallicity have not been investigated. In this paper, we show that the majority of known stars containing both debris disks and planets belong to the metal-enriched Galactic thin disk. The few exceptions are stars that seem to be born in the star formation peak occurring in times of thick disk formation (i.e., HD 10700, HD 20794, and HD 40307), that is, between 11 and

8 Gyr. The mass of the dusty disk of these three old stars measured at 70 μm is very small - in fact, it is lower than that of the Kuiper belt of our Solar system by several orders of magnitude. These results are not surprising, as they remain within the values expected for the stellar disk evolution of such primitive stars. In parallel, we found another six thick-disk stars containing only debris disks or planets. These results enable us to establish a correlation between stellar metallicity and the mass of the dust disk modulated by the different formation epochs of the thick and thin Galactic disks.