tokens: [4.5] mean magnitudes of GM Aur taken in E4 to E8. There is a significant increase of emission in both Spitzer bands in E7. MIR emission shortward of ∼20 μ m has been attributed to optically thin dust within ∼1 au of GM Aur (Calvet et al. 2005 ; Espaillat et al. 2010 ). Espaillat et al. ( 2011 ) found that GM Aur’s Spitzer spectra varied by about 10% and attributed this to variability in the mass of dust in the inner disk. Using NASA IRTF SpeX spectra covering 1–5 μ m, Ingleby et al. ( 2015 ) found that the emission varied and also attributed this to dust-mass changes. The Spitzer spectra were not coordinated with indicators, but the SpeX data were taken within a day of HST UV data. With three epochs of HST data, Ingleby et al. ( 2015 ) found that and the IR emission are roughly the same between their first two epochs (taken about 1 week apart), but both and the IR emission decreased in the third epoch (taken about four months later). Their first and second epochs had of dust in the inner disk and the third epoch had of dust in the inner disk. Here we have only two MIR magnitudes, which is not ideal for constraining the optically thin dust model. However, we can estimate the amount of dust in the inner disk in E4 through E8 by scaling with the results of Ingleby et al. ( 2015 ) under the assumption that only the dust-mass changes (Espaillat et al. 2011 ; Ingleby et al. 2015 ). The SpeX spectra cover 3.6 μ m, but not 4.5 μ m where atmospheric telluric lines are strong. Convolving the SpeX spectra with the IRAC [3.6] bandpass, we determine that the SpeX flux in the first epoch of Ingleby et al. ( 2015 ) corresponds to an IRAC [3.6] magnitude of about 8.1, which is roughly consistent with our measurements in E4, E5, E6, and E8. Therefore, we assume that the mass of dust in the inner disk in these four epochs was about the same as that seen in the first epoch of the Ingleby et al. ( 2015 ) observations. For E7, if we scale the optically thin model from the flux seen in the first epoch of the Ingleby et al. ( 2015 ) observations to the flux seen in E7, we estimate a dust mass of , corresponding to a factor of ∼2.5 change. 3.2. Centimeter Continuum Emission In Figure 2 (left), we compare the spatial brightness distribution of our 2018 data to 2015 data from Macías et al. ( 2016 ). We combine the three epochs of 2018 VLA data in this figure to achieve a high enough sensitivity to use robust weighting ( r = −0.5) and a similar angular resolution to the 2015 data. There is a seeming change in the morphology of the jet emission between 2015 and 2018. The upper right emission that Macías et al. ( 2016 ) attributed to a jet appears to be present only in the 2015 data. The resolution and sensitivity of both maps are similar, suggesting that the difference in morphology is real. However, our resolution is limited, so higher spatial resolution observations are needed to confirm this. Figure 2. Left: superposition of 3 cm VLA observations of GM Aur from
ner_tags: O O O O B-CelestialObject I-CelestialObject O O O O O O O O O O O O O O B-Telescope O O O B-Wavelength O O O B-Wavelength I-Wavelength I-Wavelength O O O O O O O O O O O B-CelestialObject I-CelestialObject B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O B-CelestialObject I-CelestialObject B-Telescope O O O O O O O O O O O O O O O O O B-CelestialObjectRegion I-CelestialObjectRegion O B-Organization B-Telescope B-Instrument O O B-Wavelength I-Wavelength I-Wavelength B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O B-Telescope O O O O O O O O B-Instrument O O O O O O O B-Telescope B-Wavelength O O O O O B-Telescope O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O O B-CelestialObjectRegion I-CelestialObjectRegion O O O O O O O O O B-CelestialObjectRegion I-CelestialObjectRegion O O O O O B-Wavelength O O O O O O O O B-Model I-Model I-Model I-Model O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O B-Citation I-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O B-Instrument O O B-Wavelength I-Wavelength I-Wavelength O O B-Wavelength I-Wavelength I-Wavelength O O O O O O O O B-Instrument O O O B-Instrument B-Wavelength I-Wavelength O O O O B-Instrument O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O B-Instrument B-Wavelength O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O B-Wavelength O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O B-Telescope O O O O O O O O O O O O O O O B-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Wavelength I-Wavelength B-Telescope O O B-CelestialObject I-CelestialObject O