Academic Journal
Cloudy with a chance of metals: Indications of CO2 in the atmosphere of GJ 1214 b from high-resolution K-band spectroscopy
| Τίτλος: | Cloudy with a chance of metals: Indications of CO2 in the atmosphere of GJ 1214 b from high-resolution K-band spectroscopy |
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| Συγγραφείς: | Nortmann L., Cont D., Lesjak F., Rains A. D., Lavail A., Boldt-Christmas L., Nagel E., Reiners A., Piskunov N., Yan F., Hatzes A., Kochukhov O., Shulyak D., Seemann U., Rengel M., Hahlin A. |
| Πηγή: | Astronomy & Astrophysics, Vol 710, p A29 (2026) |
| Στοιχεία εκδότη: | EDP Sciences, 2026. |
| Έτος έκδοσης: | 2026 |
| Συλλογή: | LCC:Astronomy |
| Θεματικοί όροι: | techniques: spectroscopic, planets and satellites: atmospheres, planets and satellites: individual: gj1214b, Astronomy, QB1-991 |
| Περιγραφή: | Context. Sub-Neptune extra-solar planets are abundant in the Milky Way, yet their atmospheric properties remain poorly understood. They frequently exhibit muted transmission spectra, with GJ1214b being the most prominent example. Following years of intense observing campaigns yielding featureless planetary spectra, more recent observations with JWST have revealed the first possible atmospheric signatures of H2O, CH4, and CO2. Aims. We present high-resolution transmission spectroscopy of GJ 1214 b based on eight transits obtained with the CRIRES+ spectrograph in the K band. Methods. We used SYSREM to remove telluric and stellar signals from the data and searched for signatures of H2O, CO, CH4, H2S, NH3, and CO2 using the cross-correlation technique. Results. We obtained non-detections for the first five molecules and used injection recovery tests to derive upper limits on the atmosphere. For CO2 we measure a cross-correlation signal at S/N ~3.6, with a detailed investigation of the signal showing no obvious indication that it is caused by correlated noise. A Welch t-test confirmed that the in-trail, in-transit distribution is significantly different from the out-of-trail distribution at a 3.4σ confidence. Interpreting the data using a Bayesian retrieval framework, with multiple molecular species and free chemistry, resulted in a retrieved planet temperature of Tiso = 398−197+283 K, consistent with a value intermediate between the day- and night-side temperatures from JWST-derived temperature-pressure profiles at high altitudes, as expected for the planetary terminator. In addition, a metallicity of [M/H]= 0.48−1.70+0.89 was derived from the abundances of the retrieved molecules, along with an opacity deck pressure of log10(Pc) = −3.04−1.53+2.52. A simpler equilibrium chemistry retrieval assuming CO2 as the sole opacity source returned a compatible temperature, with smaller formal uncertainties (Tiso = 509−59+102 K), slightly higher metallicity ([M/H]= 1.51−0.75+0.68), and higher opacity deck pressure (log10(Pc) = −0.88−2.48+1.95). While these sets of values correspond to relatively large signal amplitudes predicted for CO2 features in the mid-infrared, they are compatible with JWST NIRSpec observations within the models’ 1.5σ uncertainties. Conclusions. Further modelling and additional data are required to confirm the atmospheric signatures and obtain a comprehensive interpretation of low- and high-resolution data. Overall, our results support previous findings that CO2 is likely to be a significant component of the atmosphere of GJ 1214 b. |
| Τύπος εγγράφου: | article |
| Περιγραφή αρχείου: | electronic resource |
| Γλώσσα: | English |
| ISSN: | 0004-6361 1432-0746 |
| Relation: | https://www.aanda.org/articles/aa/full_html/2026/06/aa58512-25/aa58512-25.html; https://doaj.org/toc/0004-6361; https://doaj.org/toc/1432-0746 |
| DOI: | 10.1051/0004-6361/202558512 |
| Σύνδεσμος πρόσβασης: | https://doaj.org/article/bc46ff2f61784fa1b3a7fb7758031a6b |
| Αριθμός Καταχώρησης: | edsdoj.bc46ff2f61784fa1b3a7fb7758031a6b |
| Βάση Δεδομένων: | Directory of Open Access Journals |
| ISSN: | 00046361 14320746 |
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| DOI: | 10.1051/0004-6361/202558512 |