| Abstract: | We present the discoveries of KELT-25b (TIC 65412605, TOI-626.01) and
KELT-26b (TIC 160708862, TOI-1337.01), two transiting companions orbiting
relatively bright, early A-stars. The transit signals were initially detected
by the KELT survey, and subsequently confirmed by extit{TESS} photometry.
KELT-25b is on a 4.40-day orbit around the V = 9.66 star CD-24 5016 ($T_{
m
eff} = 8280^{+440}_{-180}$ K, $M_{star}$ = $2.18^{+0.12}_{-0.11}$
$M_{odot}$), while KELT-26b is on a 3.34-day orbit around the V = 9.95 star HD
134004 ($T_{
m eff}$ =$8640^{+500}_{-240}$ K, $M_{star}$ =
$1.93^{+0.14}_{-0.16}$ $M_{odot}$), which is likely an Am star. We have
confirmed the sub-stellar nature of both companions through detailed
characterization of each system using ground-based and extit{TESS}
photometry, radial velocity measurements, Doppler Tomography, and
high-resolution imaging. For KELT-25, we determine a companion radius of
$R_{
m P}$ = $1.64^{+0.039}_{-0.043}$ $R_{
m J}$, and a 3-sigma upper limit
on the companion’s mass of $sim64~M_{
m J}$. For KELT-26b, we infer a
planetary mass and radius of $M_{
m P}$ = $1.41^{+0.43}_{-0.51}$ $M_{
m J}$
and $R_{
m P}$ = $1.940^{+0.060}_{-0.058}$ $R_{
m J}$. From Doppler
Tomographic observations, we find KELT-26b to reside in a highly misaligned
orbit. This conclusion is weakly corroborated by a subtle asymmetry in the
transit light curve from the extit{TESS} data. KELT-25b appears to be in a
well-aligned, prograde orbit, and the system is likely a member of a cluster or
moving group. |
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