Monitoring of transiting exoplanets and their host stars with small aperture telescopes. (arXiv:2008.08379v2 [astro-ph.EP] UPDATED)

Monitoring of transiting exoplanets and their host stars with small aperture telescopes. (arXiv:2008.08379v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Salisbury_M/0/1/0/all/0/1">M.A.Salisbury</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kolb_U/0/1/0/all/0/1">U.C.Kolb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Norton_A/0/1/0/all/0/1">A.J.Norton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Haswell_C/0/1/0/all/0/1">C.A.Haswell</a>

Exoplanet research is now target rich with a wide diversity of systems making
it difficult for high demand observatories to undertake follow up observations
over extended periods of time. We investigate the effectiveness of using
0.4m-class telescopes for monitoring transiting hot Jupiters and their host
stars. We consider two representative case studies: WASP-52b with 13 new
transits, and HAT-P-23b with 17 new transits and concurrent photometric
monitoring covering 78 days. We present updated system parameters and combine
our new transit times with previously published results to calculate new
ephemerides for both systems. Our analysis of transit mid-times for WASP-52b
results in a slight preference for a quadratic ephemeris ($Deltachi_{nu}^2 =
0.07$, $Delta BIC = 1.53$ over a linear ephemeris. We discuss the reality of
this quadratic ephemeris indicating a period change of $ delta P / delta t =
-38.6pm4{rm ms~yr^{-1}}$ and consider possible causes. WASP-52 is known to be
an active star with previous publications reporting many spot crossing events,
however no such events are seen in our new photometry. Our analysis shows that
WASP-52 is still active and that the latitude of the spots has likely migrated
away from the transit chord. We confirm the inflated nature and circular orbit
for HAT-P-23b. Our monitoring of HAT-P-23 reveals a periodicity of 7.015 days
with an amplitude of 0.011 mag which we interpret as the rotation period of
HAT-P-23. The photometric and transit timing precision achieved in the case
studies shows that this class of telescope is capable of precise
characterisation and long-term monitoring of transiting hot Jupiters in support
of dedicated ongoing and future ground and space based observations.

Exoplanet research is now target rich with a wide diversity of systems making
it difficult for high demand observatories to undertake follow up observations
over extended periods of time. We investigate the effectiveness of using
0.4m-class telescopes for monitoring transiting hot Jupiters and their host
stars. We consider two representative case studies: WASP-52b with 13 new
transits, and HAT-P-23b with 17 new transits and concurrent photometric
monitoring covering 78 days. We present updated system parameters and combine
our new transit times with previously published results to calculate new
ephemerides for both systems. Our analysis of transit mid-times for WASP-52b
results in a slight preference for a quadratic ephemeris ($Deltachi_{nu}^2 =
0.07$, $Delta BIC = 1.53$ over a linear ephemeris. We discuss the reality of
this quadratic ephemeris indicating a period change of $ delta P / delta t =
-38.6pm4{rm ms~yr^{-1}}$ and consider possible causes. WASP-52 is known to be
an active star with previous publications reporting many spot crossing events,
however no such events are seen in our new photometry. Our analysis shows that
WASP-52 is still active and that the latitude of the spots has likely migrated
away from the transit chord. We confirm the inflated nature and circular orbit
for HAT-P-23b. Our monitoring of HAT-P-23 reveals a periodicity of 7.015 days
with an amplitude of 0.011 mag which we interpret as the rotation period of
HAT-P-23. The photometric and transit timing precision achieved in the case
studies shows that this class of telescope is capable of precise
characterisation and long-term monitoring of transiting hot Jupiters in support
of dedicated ongoing and future ground and space based observations.

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