4 research outputs found
Preparing an unsupervised massive analysis of SPHERE high contrast data with the PACO algorithm
We aim at searching for exoplanets on the whole ESO/VLT-SPHERE archive with
improved and unsupervised data analysis algorithm that could allow to detect
massive giant planets at 5 au. To prepare, test and optimize our approach, we
gathered a sample of twenty four solar-type stars observed with SPHERE using
angular and spectral differential imaging modes. We use PACO, a new generation
algorithm recently developed, that has been shown to outperform classical
methods. We also improve the SPHERE pre-reduction pipeline, and optimize the
outputs of PACO to enhance the detection performance. We develop custom built
spectral prior libraries to optimize the detection capability of the ASDI mode
for both IRDIS and IFS. Compared to previous works conducted with more
classical algorithms than PACO, the contrast limits we derived are more
reliable and significantly better, especially at short angular separations
where a gain by a factor ten is obtained between 0.2 and 0.5 arcsec. Under good
observing conditions, planets down to 5 MJup, orbiting at 5 au could be
detected around stars within 60 parsec. We identified two exoplanet candidates
that require follow-up to test for common proper motion. In this work, we
demonstrated on a small sample the benefits of PACO in terms of achievable
contrast and of control of the confidence levels. Besides, we have developed
custom tools to take full benefits of this algorithm and to quantity the total
error budget on the estimated astrometry and photometry. This work paves the
way towards an end-to-end, homogeneous, and unsupervised massive re-reduction
of archival direct imaging surveys in the quest of new exoJupiters.Comment: Accepted for publication in A&
Spinning up a Daze: TESS Uncovers a Hot Jupiter orbiting the Rapid-Rotator TOI-778
NASA's Transiting Exoplanet Survey Satellite (TESS) mission, has been uncovering a growing number of exoplanets orbiting nearby, bright stars. Most exoplanets that have been discovered by TESS orbit narrow-line, slow-rotating stars, facilitating the confirmation and mass determination of these worlds. We present the discovery of a hot Jupiter orbiting a rapidly rotating (vsin(i)=35.1±1.0km/s) early F3V-dwarf, HD115447 (TOI-778). The transit signal taken from Sectors 10 and 37 of TESS's initial detection of the exoplanet is combined with follow-up ground-based photometry and velocity measurements taken from Minerva-Australis, TRES, CORALIE and CHIRON to confirm and characterise TOI-778b. A joint analysis of the light curves and the radial velocity measurements yield a mass, radius, and orbital period for TOI-778b of 2.76+0.24−0.23Mjup, 1.370±0.043Rjup and ∼4.63 days, respectively. The planet orbits a bright (V=9.1mag) F3-dwarf with M=1.40±0.05Msun, R=1.70±0.05Rsun, and logg=4.05±0.17. We observed a spectroscopic transit of TOI-778b, which allowed us to derive a sky-projected spin-orbit angle of 18∘±11∘, consistent with an aligned planetary system. This discovery demonstrates the capability of smaller aperture telescopes such as Minerva-Australis to detect the radial velocity signals produced by planets orbiting broad-line, rapidly rotating stars