tokens: (95 au). Blackbody dust at ∼135 K, as found in the longest wavelength source peaking at ∼40 μ m of our HD 36546 SED (Figure 2 ) would have to be located at ∼20 au from a 20 primary. Allowing for the superheat ratio = 100 K/71 K = 1.41 found by NIRDS for dust in the HR 4796A (A0.5V) ring at ∼75 au from its primary (Lisse et al. 2017 ) moves this location out to ∼40 au, closer to the Curie et al. estimate. The remaining discrepancy between the spectral and imaging radial distance estimates might be due to our poor current characterization of the MIR–FIR SED peak; to our lack of understanding of the superheat behavior of the HD 36546 outer dust (values of out to 5–15 have been reported by Rodriguez Zuckerman 2012 and Vican et al. 2016 ); or to the different sensitivities of scattered light ( surface area*albedo) versus thermal emission ( surface area*emissivity* T 4 ) measurements of circumstellar dust in a thick disk, which will weight closer-in dust thermal emission most highly (Watson et al. 2009 and references therein). Using the T ∼ 570 K fit to the continuum underlying the warm SED excesses in Figure 2 , we find that the dust component creating the ∼8 μ m peaked emission would have to lie somewhere near 1.1 au for pure blackbody behavior, or near 2.2 au for superheated grains with . Either estimate is well within the Currie et al. coronographic masking region, so no direct comparison is possible. 5. Conclusions (1) The HD 36546 primary is a nearly unextincted early A star, not a late B star. Our modeling favors A1.5V +/−1 subclass, which is slightly later than the A0V classification found from optical spectra (Currie et al. 2017 ). Both optical and near-IR spectra rule out spectral types earlier than A0. The best-fit photospheric models require very low or no extinction, implying that HD 36546 is in front of the 1–2 Myr old Taurus–Auriga star-forming region as seen from Earth, and that there is little to no in-system extinction of the primary star. (2) There are no detected 2.1–2.5 μ m CO emission lines due to fluorescing circumstellar gas, no HBr γ lines due to accretion, and no He i 1.083 μ m, Fe ii 1.256/1.644 μ m, or S(1) 1-0 2.121 μ m emission lines due to strong wind outflow. No emission lines due to neutral PAHs are present at 3.29 μ m. (3) From 0.7 to 4.0 μ m, the SED is not “flat” or “filled-in” by inner-disk hot dust as in YSOs or transition disks. There are the beginnings of warm dust excess flux in the 4.5–5.0 μ m region, agreeing with archival JHKLM photometry of the system (triangles in Figure 2 ) showing a rise in M-band and WISE W2. (4) There are indications of an unusual local maximum in the SED at 6–9 μ m. A similar feature was seen in the A3V, ∼10 Myr old debris disk system HD 131488 and at lower SNR for the similarly bright HD 121191 system (A8V, ∼10 Myr) by Melis et al. ( 2013 ) using T-ReCS. The Mittal et al. ( 2015 ) Spitzer /IRS disk survey contains another good spectral match, the HD 148657 (A7V, 12 Myr) system. The
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