  Chromospheric activity cycles are common in late-type stars; however, only a
handful of coronal activity cycles have been discovered. \ihor\ is the most
active and youngest star with known coronal cycles. It is also a young solar
analog, and we are likely facing the earliest cycles in the evolution of
solar-like stars, at an age (~600 Myr) when life appeared on Earth. Our aim is
to confirm the ~1.6 yr coronal cycle and characterize its stability over time.
We use X-ray observations of iota Hor to study the corona of a star
representing the solar past through variability, thermal structure, and coronal
abundances. We analyzed multi-wavelength observations of iota Hor using
XMM-Newton, TESS, and HST data. We monitored iota Hor throughout almost seven
years in X-rays and in two UV bands. The summed RGS and STIS spectra were used
for a detailed thermal structure model, and the determination of coronal
abundances. We studied rotation and flares in the TESS light curve. We find a
stable coronal cycle along four complete periods, more than covered in the Sun.
There is no evidence for a second longer X-ray cycle. Coronal abundances are
consistent with photospheric values, discarding any effects related to the
first ionization potential. From the TESS light curve we derived the first
photometric measurement of the rotation period (8.2 d). No flares were detected
in the TESS light curve of iota Hor. We estimate the probability of having
detected zero flares with TESS to be ~2%. We corroborate the presence of an
activity cycle of ~1.6 yr in iota Hor in X-rays, more regular than its Ca II
H&K counterpart. A decoupling of the activity between the northern and southern
hemispheres of the star might explain the disagreement. The inclination of the
system would result in an irregular behavior in the chromospheric indicators.
The more extended coronal material would be less sensitive to this effect.
