The SDSS-2MASS-WISE Ten Dimensional Stellar Color Locus

Abstract

We present the fiducial main sequence stellar locus traced by 10 photometric colors observed by SDSS, 2MASS, and WISE. Median colors are determined using 1,052,793 stars with r-band extinction less than 0.125. We use this locus to measure the dust extinction curve relative to the r-band, which is consistent with previous measurements in the SDSS and 2MASS bands. The WISE band extinction coefficients are larger than predicted by standard extinction models. Using 13 lines of sight, we find variations in the extinction curve in H, Ks, and WISE bandpasses. Relative extinction decreases towards Galactic anti-center, in agreement with prior studies. Relative extinction increases with Galactic latitude, in contrast to previous observations. This indicates a universal mid-IR extinction law does not exist due to variations in dust grain size and chemistry with Galactocentric position. A preliminary search for outliers due to warm circumstellar dust is also presented, using stars with high signal-to-noise in the W3-band. We find 199 such outliers, identified by excess emission in Ks-W3. Inspection of SDSS images for these outliers reveals a large number of contaminants due to nearby galaxies. Six sources appear to be genuine dust candidates, yielding a fraction of systems with infrared excess of 0.12$\pm$0.05%.

11 pages, 10 figures, MNRAS Accepted. Tables 1 and 2 available online: https://github.com/jradavenport/wise_locus

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Cited by in corpus (6)

• BOSS Ultracool Dwarfs I: Colors and Magnetic Activity of M and L dwarfs
• A three dimensional extinction map of the Galactic Anticentre from multi-band photometry
• Stellar loci I. Metallicity dependence and intrinsic widths
• Stellar loci III: Photometric metallicities for half million FGK stars of Stripe 82
• Collisions of Terrestrial Worlds: The Occurrence of Extreme Mid-Infrared Excesses around Low-Mass Field Stars
• SDSSJ14584479+3720215: A Benchmark JHK Blazar Light Curve from the 2MASS Calibration Scans