ALMA and VLA Observations of the HD 141569 System
  We present VLA 9 mm (33 GHz) observations of the HD 141569 system from
semester 16A. The observations achieve a resolution of 0.25 arcsec ($\sim28$
au) and a sensitivity of $4.7~\mu \rm Jy~beam^{-1}$. We find (1) a $52\pm
5~\mu$Jy point source at the location of HD 141569A that shows potential
variability, (2) the detected flux is contained within the SED-inferred central
clearing of the disc meaning the spectral index of the dust disc is steeper
than previously inferred, and (3) the M dwarf companions are also detected and
variable. Previous lower-resolution VLA observations (semester 14A) found a
higher flux density, interpreted as solely dust emission. When combined with
ALMA observations, the VLA 14A observations suggested the spectral index and
grain size distribution of HD 141569's disc was shallow and an outlier among
debris systems. Using archival ALMA observations of HD 141569 at 0.87 mm and
2.9 mm we find a dust spectral index of $\alpha_{\rm mm} = 1.81\pm 0.20$. The
VLA 16A flux corresponds to a brightness temperature of $\sim5\times10^{6}$ K,
suggesting strong non-disc emission is affecting the inferred grain properties.
The VLA 16A flux density of the M2V companion HD 141569B is $149\pm9~\mu$Jy,
corresponding to a brightness temperature of $\sim2\times10^{8}$ K and
suggesting significant stellar variability when compared to the VLA14A
observations, which are smaller by a factor of $\sim6$.
