A Correlation between Pre-Main-Sequence Stellar Rotation Rates and IRAC Excesses in Orion

• Published in: The Astrophysical journal Vol. 646; no. 1; pp. 297 - 303
• Main Authors: Rebull, L. M, Stauffer, J. R, Megeath, S. T, Hora, J. L, Hartmann, L
• Format: Journal Article
• Language: English
• Published: Chicago, IL IOP Publishing 20.07.2006; University of Chicago Press
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Rotation speed; Open clusters; Stellar rotation; stars: rotation; Correlations; open clusters and associations: individual (Orion)
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/504865

Early observations of T Tauri stars suggested that stars with evidence of circumstellar accretion disks rotated slower than stars without such evidence, but more recent results are not as clear. Near-IR circumstellar disk indicators, although the most widely available, are subject to uncertainties that can result from inner disk holes and/or the system inclination. Mid-infrared observations are less sensitive to such effects, but until now, these observations have been difficult to obtain. The Spitzer Space Telescope now easily enables mid-infrared measurements of large samples of PMS stars covering a broad mass range in nearby star-forming regions. Megeath and collaborators surveyed the Orion Molecular Clouds (61 Myr) with the IRAC instrument (3.6, 4.5, 5.8, 8 km) as part of a joint IRAC and MIPS GTO program. We examine the relationship between rotation and Spitzer mid-IR fluxes for 6900 stars in Orion for stars between 3 and 0.1 M sub(z). We find in these Spitzer data the clearest indication to date that stars with longer periods are more likely than those with short periods to have IR excesses suggestive of disks.