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Using the NASA/IRTF SpeX & BASS spectrometers we have obtained novel 0.7 - 13um observations of the newly imaged HD36546 debris disk system. The SpeXspectrum is most consistent with the photospheric emission expected from anLstar ~ 20 Lsun, solar abundance A1.5V star with little/no extinction andexcess emission from circumstellar dust detectable beyond 4.5 um.Non-detections of CO emission lines and accretion signatures point to the gaspoor circumstellar environment of a very old transition disk. Combining theSpeX and BASS spectra with archival WISE/AKARI/IRAS/Herschel photometery, wefind an outer cold dust belt at ~135K and 20 - 40 AU from the primary, likelycoincident with the disk imaged by Subaru (Currie et al. 2017), and a newsecond inner belt with temperature ~570K and an unusual, broad SED maximum inthe 6 - 9 um region, tracing dust at 1.1 - 2.2 AU. An SED maximum at 6 - 9 umhas been reported in just two other A-star systems, HD131488 and HD121191, bothof ~10 Myr age (Melis et al. 2013). From Spitzer, we have also identified the~12 Myr old A7V HD148567 system as having similar 5 - 35 um excess spectralfeatures (Mittal et al. 2015). The Spitzer data allows us to rule out wateremission and rule in carbonaceous materials - organics, carbonates, SiC - asthe source of the 6 - 9 um excess. Assuming a common origin for the 4 youngAstar systems' disks, we suggest they are experiencing an early era ofcarbon-rich planetesimal processing.

Spectral Evidence for an Inner Carbon-Rich Circumstellar Dust Belt in the Young HD36546 A-Star System