Titan ESPRESSO and UVES spectra

The optical spectra of Titan reveal a rich set of absorption features, most of which are likely associated with methane (CH_4_). Methane is a key molecule in planetary and exoplanetary atmospheres, yet a comprehensive high-resolution linelist at optical wavelengths remains incomplete. This study identified and characterized potential CH_4_ absorption features in high-resolution optical spectra of Titan, providing essential data for linelist development and improving CH_4_ detection and characterization. We analyzed Titan spectra from the ESPRESSO spectrograph (R~190000), identifying intrinsic features and measuring their relative strengths. A conservative detection approach was employed, slightly overestimating solar and telluric contributions to distinguish them from Titan's intrinsic features. To assess the impact of spectral resolution, we compared the ESPRESSO data with Titan UVES data (R~110000). We identified 6195 absorption features in the ESPRESSO spectra potentially associated with CH_4_, of which 5436 are newly reported. ESPRESSO detected twice as many features as UVES in overlapping regions, highlighting the advantage of higher-resolution data. Most detected lines remained unresolved, so our reported features are primarily blended absorption structures. We estimated the detection limit for feature identification to correspond to a CH_4_ absorption coefficient of approximately 0.02km/am. Comparison of our results with a previous analysis of Titan UVES spectra and with experimental CH_4_ data at a similar temperature showed good agreement, while some discrepancies were observed when compared with data acquired at a different temperature. We provide a comprehensive list of Titan absorption features with key reliability metrics, along with Titan's intrinsic spectra, to support future studies.

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/AJ/170/315
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/170/315
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/170/315
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/AJ/170/315
Provenance
Creator Sithajan S.; Kaewbiang L.; Jones H.R.A.; Rittipruk P.; Meethong S.
Publisher CDS
Publication Year 2025
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Solar System Astronomy