0 Assigned ID: 2387 ----- Attempting Submission 1 (Fri Apr 09 22:50:17 GMT 2021) ----- For the best data quality, it is generally required to use all four FP-POS positions when observing at a given COS cenwave. See the COS Instrument Handbook for exceptions that may apply to observations with G130M/1291 or G160M. --- 24 March 2023 - Resubmission with PHASE changed for visit 03 --- 6 July 2022 - Resubmission of a single visit (5 orbits) removed from Cycle 29 to be planned for Cycle 30. 2085731995 ----- Attempting Submission 1 (Tue Jul 06 21:12:49 GMT 2021) ----- HST Phase II Proposal 16726 successfully submitted. Receipt: # 16726-1 ----- Attempting Submission 2 (Tue Jul 06 21:32:11 GMT 2021) ----- HST Phase II Proposal 16726 successfully submitted. Receipt: # 16726-2 ----- Attempting Submission 3 (Fri Jul 09 16:00:46 GMT 2021) ----- ----- Attempting Submission 4 (Fri Oct 15 10:01:35 GMT 2021) ----- ----- Attempting Submission 5 (Fri Oct 22 13:17:37 GMT 2021) ----- ----- Attempting Submission 6 (Wed Apr 27 18:31:53 GMT 2022) ----- ----- Attempting Submission 7 (Wed Jul 06 14:46:05 GMT 2022) ----- ----- Attempting Submission 8 (Fri Mar 24 14:59:12 GMT 2023) ----- Proposal resubmitted as is, with the FP-POS position 3 selected, which seems to generate a Warning message. Photo-evaporation of planetary atmospheres plays a key role in the evolution of exoplanets, carving their whole population. However, direct observations of atmospheric escape are scarce and almost non-existent in the mass range of super-Earths and mini-Neptunes, while these planets are among the most impacted by the phenomenon. A huge step forward could be made by achieving a comparative study of several super-Earths, volatile-rich or not, in a single multi-planet system: such planets would indeed experience the same evolution of the stellar X and EUV flux that are driving atmospheric escape. The perfect system for such a study has just been identified: the nearby, solar-type, and naked-eye star nu^2 Lupi hosts transiting planets spanning a remarkably large range of insolation (~100 to ~5x the insolation of Earth). TESS found the transits of the two inner planets and CHEOPS detected the transit of planet d, a volatile-rich super-Earth with an exceptional period of 107 day. These super-Earths straddle the radius gap of the "evaporation valley" and could have retained different fractions of gas and volatiles. Like for previously observed warm Neptunes, they could be enshrouded in huge comet-like exospheric clouds of escaping gas, which could have built up in the mild radiative environment. The system unique combination of proximity, brightness and favorable planet characteristics offers a fantastic opportunity to exploit HST ultraviolet capabilities to search for the hydrogen, oxygen and carbon escaping three planets in whole new mass and irradiation regimes. It is the ideal testbed for advancing both observations and theories of atmospheric evaporation of exoplanets. We are targetting transits of exoplanets in the Nu2 Lupi system at Lyman-alpha. Nu2 Lupi is a naked-eye star (V=5.65). We will observe it with COS/FUV/G130M using both segments B (incl. Lyman-alpha) and A. The Lyman-alpha airglow will be corrected using available airglow templates, as in programs GO14877 (Bourrier et al. 2018, A&A 615, A117) and GO14767 (Dos Santos et al. 2019, A&A 629, A47). We wish to use only one FP-POS setting per visit so we are not impacted by the restriction to FP-POS=3 or 4 that applies when using segment B. We have set FP-POS=3 through the whole program. Each visit will consist in 5 HST orbits, spent in a single, orbit-long exposure in time-tag mode. The first orbit in each visit additionally contains an acquisition performed with COS/NUV in imaging mode, using the Bright Object Aperture and MIRRORB. The transit observations are time-critical: we aim at obtaining two transits (2x5 orbits) of planet b, three transits (3x5 orbits) of planet c, and three transits (3x5 orbits) of planet d. Planet b transits every ~11 days and there is a dozen windows available until March 2023. Planets c and d have longer periods and they are much more constraining in terms of planning: with its ~27-day period, there are only 4 windows available for transits of c between now and March 2023, with a first opportunity on 21 September 2021 (still in Cycle 28) and two beyond Cycle 29. Finally, planet d has an even longer period of ~107 days; there are 3 opportunites: one on 11 August 2021 (Cycle 28), one on 14 March 2022 (Cycle 29) and one on 29 Jan 2023 (Cycle 30). The proposal anticipated that one visit (5 orbits) would be carried over in Cycle 30; it might actually be up to three visits (15 orbits). Besides, the visits have slightly difference phase constraints, set to cover different parts of the transits. PI Ehrenreich is an expert in UV observations of exoplanets with HST. He led and participated to many HST programs. Together with Co-Is Vidal-Madjar, Lecavelier des Etangs, Fossati, Bourrier, Lavie and Dos Santos, they pioneered the field of atmospheric escape of exoplanets and have discovered most of the known cases (Vidal-Madjar et al. 2003, 2004; Lecavelier des Etangs et al. 2010, 2012; Fossati et al. 2010; Ehrenreich et al. 2015; Bourrier et al. 2018; Dos Santos et al. 2020). They are experts in HST instrumentation, in particular STIS and COS. Recently, Co-Is Vidal-Madjar, Lecavelier des Etangs, Bourrier and Dos Santos managed to correct for the nefarious airglow contamination in COS observations at H I Lyman-a and O I (Wilson et al. 2017; Bourrier et al. 2018b; Dos Santos et al. 2019). The team has also developed the reference theoretical tools to interpret observations of atmospheric escape: the EVE code (Bourrier & Lecavelier des Etangs 2013) has been used at many occasions and provided predictions for the spectacular case of the warm Neptune GJ 436b, which have been verified by subsequent observations (Lavie et al. 2017). The team is also composed by CHEOPS consortium members who have discovered the transit of nu2 Lup d: the PI is also the mission scientist of CHEOPS and coordinated the CHEOPS Early Science program featuring the target; Co-I Delrez has led the work on transit data analysis and interpretation, with support from Co-Is Deline, Lendl, Brandeker, Fridlund and Pagano. Co-Is Alibert, Fossati and Heng provided key insights into the planet internal structures and atmospheric evolution, which are the scientific bases for this proposal. The team can confirm that CHEOPS will observe the transit of planet d again at the end of April 2021 to obtain a precise ephemeris. The current ephemeris, relying on one transit and many RV measurements, is already good enough to quantify the number of windows of opportunity for HST. The team will react fast to update the ephemeris and prepare the Phase 2. It is equipped with the competence and all tools necessary for rapid analysis and interpretation of the results. Exoplanets and Exoplanet Formation 6 false true false false false false AVAILABLE STAR EXTRA-SOLAR PLANETARY SYSTEM G V-IV NO HD136352 J2000 J2000 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 COS/FUV Spectroscopic No No G130M 1291 1738614451528 The scheduling data was generated by CASM 31.0. 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