27 May 2022 The third and final Announcement of Opportunity (AO3) for the CHEOPS Guest Observers Programme in the nominal mission came out on 15 February 2022, and closed  4 weeks later on 15 March 2022. A total of 38 proposals were submitted to the AO, with an oversubscription factor of ~ 2.4 on the time available at the opening of the Call. Given the demand on CHEOPS observing time it was agreed with the mission PI that observing time that was not allocated from Year 2 could be taken forward to Year 3. As a result a total of 25% of the science time in the period 1 July 2022 to 24 September 2023 is available to the GO Programme. 

It was decided to allocate approximately 85% of the GO Programme time to proposals submitted to AO-3, with the remainder to be made available to the Community through the Discretionary Proyramme. Approximately 30% more orbits than can be physically scheduled in the AO-3 component of the GO Programme have been allocated to enable efficient scheduling of the very large number of time-critical observations in CHEOPS programmes. 

The CHEOPS Time Allocation Committee (TAC) met on 11-13 May, 2022. Based on the recommendations made by the TAC, the Director of Science has awarded observing time on CHEOPS to the proposals listed in the table below.  Successful proposals, known as programmes, have been awarded observing time on CHEOPS totalling 1546.8 orbits. Targets that are part of these programmes have been added to the Reserved Target List and cannot be included in observing programmes of others until the AO-3 observations have been completed. 

All programmes have been assigned a priority from 1 (high) to 3 (low), in some cases at the level of individual targets. This priority is taken into account by the automated planning tool used in the weekly planning, and is a strong indicator of the likelihood that observations will be scheduled. Observers are reminded that the award of observing time provides no guarantee that the observations will be executed, and that more observing time has been awarded than can be physically scheduled to minimise the time that the CHEOPS satellite is idle.

Principal Investigators of proposals that have been awarded time will be contacted by email, and are required to complete and submit observation requests at their earliest convenience. Guidelines on how to prepare observation requests can be found in the document at this link. Feedback will be provided to the PIs of proposals that were not awarded observing time. 


Key to table:   EP - exoplanet science; SP - stellar physics





# orbits


 1  Worthey (US);  Masses, radii, and limb darkening on the lower main sequence  24  P3
 2  Kálmán (HU)  Investigating the multicolor phase curves of underexplored giant exoplanets  96  P3
 3  Heitzmann (US)  Two sub-Neptunes in short orbit around two bright young G and K stars  15  P2
 4  Deeg (ES)  Determining the internal structure of the young hierarchical triple HD 144548  81  P1
 8  Ing-Guey Jiang (CN)  Bridging CHEOPS and Twinkle: forming long TTV baselines for the multi-planet system K2-266  42  P2
 9  Isaak (NL)  CHEOPS @ School - building bridges between education and space science  20  P1
 10  Lowson (AU)  Two baby sub-Neptunes, one visit: a snapshot of atmosphere evolution  10  P1
 11  Yang (CN)  Transit Timing Variations of XO-3b: gaining insights into the orbital evolution of a hot Jupiter  21  P2
 13  Garai (HU)  Exploiting the color difference between CHEOPS and TESS for exoplanet candidate validation  68  P3
 14  Changeat (UK)  Atmospheric characterisation of the hot-Jupiter WASP-79 b with CHEOPS  28  P3
 16  Teinturier (FR)  CHEOPS Phase Curves to Characterize the Clouds Composition of Hot Jupiters  38  P2
 17  Osborne (UK)  Refining radii for planets in the radius valley  18  P3
 18  Patel (SE)  Constraining the morning and evening limbs of the hot jupiters WASP-79b and WASP-101b  159  83 (P1), 76(P2)
 19  Gressier (UK)  Cloudiness of three warm Sub-Neptunes  21  P2
21*  Dragomir (US)  Exploring the Diversity of Small Planet Compositions  61.3  P1
22   Jenkins (CL)   Confirming the Eclipse Variability of the Ultrahot Neptune, LTT 9779b 50  P2
23  Fairnington (AU)  The TTVs of a compact planetary system around an early-type star with CHEOPS  43  P2
 24  Scarsdale (US)  Photometric Confirmation of The Brightest-Host Transiting Habitable Zone Terrestrial Exoplanet  9  P1
 26  Edwards (FR)  Ephemeris Refinement of Key Targets for the ESA-Ariel Mission  132  P2
 27   Eisner(UK)  Readying a warm sub-Neptune orbiting around the bright, Sun-like star TOI-4320, for future atmospheric characterisation  9  P1
 28  Wilson (UK)  Hunting for a Transit of a HARPS-N Known Exoplanet Target around a TESS Blend<  52.1  P1
 29  Saba (UK)  Constraining Refractory Species and Characterising the Stellar Environment of the Inflated hot-Jupiter WASP-17 b  20  P2
 30  Lillo-Box (ES)   Unveiling the origin of an in-phase additional dimming in the TESS light curve of a known exoplanet  20.4  P1
 32  Damasso (IT)  Pinning down orbital period, transit ephemeris, and radius of the infant planet V1298 Tau e  112  P1
 34  Edwards (FR)  Rescuing Longer Period TESS Planet Candidates for Future Atmospheric Characterisation   130  P2
  35*  Merin Martin (ES)   Dynamical masses and bulk compositions of newly-found TESS and ASTEP-confirmed sub-Neptunes  30  P2
 36  Ramos Gomes (BR)  Stellar Occultation by Minor Bodies in our Solar System with CHEOPS  5  P1
  37   Fors (ES)  K2-149: unveiling planet interaction of the 2nd most highly packed system with four new sub-Neptunes.  192  40 (P2), 152 (P3)
  38  Wu (CN)  Precise Mass Measurement for the Compact Object in LS 5039: The Heaviest Neutron Star or the Lightest Stellar-mass Black Hole?  40   P2





Note: programmes #21 and #35 have a target in common.  Given the similarity of the proposed observation, a single observation will be made and the data shared.