| 1. |
- Hansen, Jonah T., et al.
(författare)
-
The Pyxis Interferometer (I) : Scientific Context, Metrology System and Optical Design
- 2022
-
Ingår i: Optical and infrared interferometry and imaging VIII. - : SPIE - International Society for Optical Engineering. - 9781510653481 - 9781510653474
-
Konferensbidrag (refereegranskat)abstract
- Optical interferometry from space is arguably the most exciting prospect for high angular resolution astrophysics; including the analysis of exoplanet atmospheres. This was highlighted in the recent ESA Voyage 2050 plan, which pointed out the exciting potential of this technology, but also indicated the critical need for technological demonstrators. Here we present the Pyxis interferometer; a ground-based pathfinder for a CubeSat space interferometer, currently being built at Mt Stromlo Observatory. We outline its technological and scientific potential as the only visible wavelength interferometer in the Southern Hemisphere, and the optical systems designed to provide CubeSat compatible metrology for formation flying.
|
|
| 2. |
- Wehrhahn, Ansgar, et al.
(författare)
-
CRIRES+ detection of H2O and CO in the transmission spectra of WASP-107 b
- 2022
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- WASP-107 b is a warm super-Neptune with a large extended atmosphere orbiting a bright K dwarf of solar composition. The planet's size and the brightness of its stellar host make it highly amenable to atmospheric characterisation, with previous detections of both He and H2O. We observe it here for the first time in high-resolution spectroscopy in the K-band. To obtain a transmission spectrum of the exoplanet atmosphere, we observe a transit event of WASP-107 b for a total of 5.4 hours (2.7 hours in transit) in the K-band with an average SNR = 64 for each exposure using the high-resolution infrared CRIRES+ spectrograph on the Very Large Telescope on Cerro Paranal, Chile. We aim to demonstrate the capabilities of this new instrument for exoplanet characterisation by searching for the presence of molecular features of key chemical species in the atmosphere with spectral lines detectable in this band, such as CO, CO2, H2O, and CH4. The search for particular chemical species is conducted by using the cross-correlation method on the observed spectra. The transit spectroscopy observations are first cleaned from the stellar and telluric features using the SYSREM algorithm, and the remaining spectral information is then compared to a model transmission spectrum. The model transmission spectrum is obtained using the petitRADTRANS code based on expectations for a warm Neptune-class planet and the observed orbital parameters. We report the detection of H2O in the atmosphere of WASP-107 b with 4.71 sigma significance, as well as a detection of CO at 3.46 sigma. The velocities of these detections show signs of atmospheric weather patterns, such as day-to-night-side temperature gradients. We do not detect the presence of CO2 or CH4. Our results confirm the chemical composition of the WASP-107 b's atmosphere and pave the way for efficient atmospheric studies of other planets of the same class. They show that the newly upgraded high-resolution spectrograph CRIRES+ is suitable for exoplanet transit observations. All detections and non-detections are in agreement with previous transmission studies of WASP-107 b based on low-resolution spectroscopy.
|
|
