Observations sub-WG

Context and Objectives

To perform a meaningful choice of the final Ariel planetary systems we need to globally characterise the stars well before the launch (Danielski et al., 2022). The success of Ariel depends on the homogeneous and precise determination of the stellar atmospheric parameters, elemental abundances, activity, etc. Thus, the refinement of the stellar host properties using both high-quality data and a uniform approach to the data analysis is crucial. Our goal is to derive these data.

The purpose of this sub-WG is to supply other sub-groups with sufficient observations. First and foremost we collect high-resolution spectra of the Ariel target stars, aiming for their high signal-to-noise ratio (SNR), typically around 200. Almost all confirmed planets have been followed-up spectroscopically, and we gladly make use of these observations, relying on data stored in public archives, and often stacking multiple low-SNR spectra into one (combined) of satisfactory quality. When the archival material is absent, has insufficient SNR, or precise parameters and abundances can not be determined from it (e.g. parts of spectra crucial for C,N,O abundance determination are missing), we perform our own dedicated observations, using a number of telescopes (e.g. LBT, TNG, SALT, VLT).

To take into account the variability of the host stars (spots, flares, granulation), and understand its influence on the derived planetary properties, we also monitor a number of stars photometrically, either via multi-band observations from the ground (e.g. REM), or from space (TESS, CHEOPS).

High-resolution spectrum of TOI-677 from one of our programmes. The SNR reaches 230 around 7400 Å.

Our observational campaign

Since 2019 we have been monitoring/observing stars within the Ariel Mission Candidate Sample

2025 ESO/UVES observing programme (ID 115.28DT, 41.4h, PI Danielski)
2024 CFHT/SPIRou+ESPaDOnS (ID 24AF008, 38.5h, PI Bellotti)
2024 Palomar/TripleSpec and DoubleSpec observing programme (ID J15, 2 nights, PI Ciardi).
2024 - 2026 SALT/HRS observing large programme ( ID 2024-1-MLT-010, 120h, PI Hełminiak)
2023 CHEOPS SoM programme “Characterising granulation in the Ariel Reference Sample” (ID 900, 310h, PI Bruno).
2023 TBL/NEONARVAL observing programme (ID 2023B PNPS 11, 17.8h, PI Bellotti).
2023 CFHT/SPIRou+ESPaDOnS (ID 23BF019, 28.9h, PI Bellotti)
2023 SALT/HRS observing programme (ID 2023-1-SCI-005, 18h, PI Hełminiak)
2023 ESO/UVES observing programme (ID 111.2442, 43.6h, PI Danielski)
2023 TBL/NEONARVAL observing programme (ID 2023A PNPS 8, 29.6h, PI Bellotti)
2023 CFHT/SPIRou+ESPaDOnS (ID 23AF016, 35.9h, PI Bellotti)
2023 LBT/PEPSI observing programme (ID 2022 2023 , 22B 024, 7.36h, PI Rainer)
2022 TNG/HARPS-N observing programme (ID A46TAC 27, 8h, PI Rainer).
2022 ESO/UVES observing programme (ID 110.24BU, 35.5h, PI Danielski)
2022 CFHT/SPIRou+ESPaDOnS (ID 22BF023, 26.7hm, PI Bellotti)
2022 ESO/HARPS-Pol observing programme (ID 110.24C8, 17.6h, PI Bellotti)
2022 ESO/REM INAF observing programme (ID AOT45 36, 38.6h, PI Bruno)
2022 Asiago-Ekar INAF observing programme (Large programme, 22 nights, PI Claudi)
2022 ESO/UVES observing programme (ID 109.23J9, 29.75h, PI Danielski)
2021 LBT/PEPSI observing programme (ID 2021 2022 25, 20h, PI Rainer)
2020 ESO/UVES observing programme (ID 106.21QS, 22.33h, PI Danielski)
2020 TNG/HARPS-N observing programme (ID A42TAC 20, 9h, PI Rainer)
2019 ESO/UVES observing programme (ID105.20P2, 30.23h, PI Danielski)
2019 TNG/HARPS-N observing programme (ID A41TAC 45, 9h, PI Benatti)

Archival Data

We are browsing through public archives and extracting high-quality data

ESO Archive (HARPS, FEROS, UVES, ESPRESSO)
OHP Archives (SOPHIE, ELODIE)
TNG Archive (HARPS-N, SARG)
Keck Observatory Archive (HIRES)
ExoFOP (TrES)

The coordinators

Monica Rainer
(INAF-OABrera, Merate, Italy)

As one of the coordinators of the sub-WG, Monica contributes to the proposals writing and the archive mining. She also supports the analysis sub-WGs with data troubleshooting.

Krzysztof Hełminiak
Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences, Toruń, Poland

Krzysztof coordinates the activities of the sub-group, especially proposals for the high-resolution spectroscopic observations and gathering archival data.

The subWG members

Katia Biazzo (INAF - Osservatorio Astronomico di Roma, Italy)

Giovanni Bruno (INAF - Osservatorio Astronomico di Catania, Italy)

Laura Magrini (INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy)

Elisa Delgado Mena (Instituto de Astrofísica e Ciências do Espaço, Porto, Portugal)

Ronaldo Oliveira Da Silva (INAF - Osservatorio Astronomico di Roma, Italy)

Heleri Ramler (Tartu Observatory, Tartu, Estonia)

Nicoletta Sanna (INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy)

Maria Tsantaki (INAF - Osservatorio Astrofisico di Arcetri, Florence, Italy)

Sergio Sousa (Instituto de Astrofísica e Ciências do Espaço, Porto, Portugal)

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