New debris disk candidates: 24 micron stellar excesses at 100 Myr

• Published in: arXiv.org
• Main Authors: Gorlova, Nadya, Padgett, Deborah L, Rieke, George H, Muzerolle, James, Morrison, Jane E, Engelbracht, Chad W, Gordon, Karl D, Hines, Dean C, Hinz, Joannah C, Noriega-Crespo, Alberto, Rebull, Luisa, Stansberry, John A, Stapelfeldt, Karl R, Su, Kate Y L, Young, Erick T
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 01.06.2004
• Subjects: Debris; Main sequence stars; Solar system
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0406041

Sixty three members of the 100 Myr old open cluster M47 (NGC 2422) have been detected at 24 micron with Spitzer. The Be star V 378 Pup shows an excess both in the near-infrared and at 24 micron (K-[24] = 2.4 mag), probably due to free-free emission from the gaseous envelope. Seven other early-type stars show smaller excesses, K-[24] = 0.6-0.9. Among late-type stars, two show large excesses: P922 - a K1V star with K-[24] = 1.08 pm 0.11 and P1121 - an F9V star with K-[24] = 3.72 pm 0.02. P1121 is the first known main-sequence star showing an excess comparable to that of beta Pic, which may indicate the presence of an exceptionally massive debris disk. It is possible that a major planetesimal collision has occurred in this system, consistent with the few hundred Myr time scales estimated for the clearing of the Solar System.