Seemann, Ulf

[["dc.bibliographiccitation.artnumber","A40"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","563"],["dc.contributor.author","Chen, G."],["dc.contributor.author","van Boekel, R."],["dc.contributor.author","Wang, H."],["dc.contributor.author","Nikolov, N."],["dc.contributor.author","Fortney, J. J."],["dc.contributor.author","Seemann, U."],["dc.contributor.author","Wang, W."],["dc.contributor.author","Mancini, L."],["dc.contributor.author","Henning, Th."],["dc.date.accessioned","2019-07-09T11:40:19Z"],["dc.date.available","2019-07-09T11:40:19Z"],["dc.date.issued","2014"],["dc.description.abstract","Aims. WASP-43b is the closest-orbiting hot Jupiter, and it has high bulk density. It causes deep eclipse depths in the system’s light curve in both transit and occultation that is attributed to the cool temperature and small radius of its host star. We aim to secure a broad-band transmission spectrum and to detect its near-infrared thermal emission in order to characterize its atmosphere. Methods. We observed one transit and one occultation event simultaneously in the g′, r′, i′, z′, J, H, K bands using the GROND instrument on the MPG/ESO 2.2-m telescope, where the telescope was heavily defocused in staring mode. After modeling the light curves, we derived wavelength-dependent transit depths and flux ratios and compared them to atmospheric models. Results. From the transit event, we have independently derived WASP-43’s system parameters with high precision and improved the period to be 0.81347437(13) days based on all the available timings. No significant variation in transit depths is detected, with the largest deviations coming from the i′-, H-, and K-bands. Given the observational uncertainties, the broad-band transmission spectrum can be explained by either (i) a flat featureless straight line that indicates thick clouds; (ii) synthetic spectra with absorption signatures of atomic Na/K, or molecular TiO/VO that in turn indicate cloud-free atmosphere; or (iii) a Rayleigh scattering profile that indicates high-altitude hazes. From the occultation event, we detected planetary dayside thermal emission in the K-band with a flux ratio of 0.197 ± 0.042%, which confirms previous detections obtained in the 2.09 μm narrow band and KS-band. The K-band brightness temperature 1878+108-116 K favors an atmosphere with poor day- to nightside heat redistribution. We also have a marginal detection in the i′-band (0.037+0.023-0.021%), corresponding to TB = 2225+139-225 K, which is either a false positive, a signature of non-blackbody radiation at this wavelength, or an indication of reflective hazes at high altitude."],["dc.format.extent","14"],["dc.identifier.doi","10.1051/0004-6361/201322740"],["dc.identifier.fs","609741"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10911"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58144"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","Broad-band transmission spectrum and K-band thermal emission of WASP-43b as observed from the ground"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A3"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","556"],["dc.contributor.author","Mueller, A."],["dc.contributor.author","Roccatagliata, V."],["dc.contributor.author","Henning, Th."],["dc.contributor.author","Fedele, D."],["dc.contributor.author","Pasquali, A."],["dc.contributor.author","Caffau, E."],["dc.contributor.author","Rodriguez-Ledesma, M. V."],["dc.contributor.author","Mohler-Fischer, M."],["dc.contributor.author","Seemann, U."],["dc.contributor.author","Klement, R. J."],["dc.date.accessioned","2018-11-07T09:21:42Z"],["dc.date.available","2018-11-07T09:21:42Z"],["dc.date.issued","2013"],["dc.description.abstract","Aims. We reanalyze FEROS observations of the star HIP 11952 to reassess the existence of the proposed planetary system. Methods. The radial velocity of the spectra were measured by cross-correlating the observed spectrum with a synthetic template. We also analyzed a large dataset of FEROS and HARPS archival data of the calibrator HD 10700 spanning over more than five years. We compared the barycentric velocities computed by the FEROS and HARPS pipelines. Results. The barycentric correction of the FEROS-DRS pipeline was found to be inaccurate and to introduce an artificial one-year period with a semi-amplitude of 62 m s(-1). Thus the reanalysis of the FEROS data does not support the existence of planets around HIP 11952."],["dc.description.sponsorship","DLR [50 OR 1109]; Bayerischen Gleichstellungsforderung (BGF)"],["dc.identifier.doi","10.1051/0004-6361/201321497"],["dc.identifier.isi","000323893500003"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10864"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29170"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Reanalysis of the FEROS observations of HIP 11952 (Research Note)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A6"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","564"],["dc.contributor.author","Chen, G."],["dc.contributor.author","van Boekel, R."],["dc.contributor.author","Madhusudhan, N."],["dc.contributor.author","Wang, H."],["dc.contributor.author","Nikolov, N."],["dc.contributor.author","Seemann, U."],["dc.contributor.author","Henning, Th."],["dc.date.accessioned","2019-07-09T11:40:19Z"],["dc.date.available","2019-07-09T11:40:19Z"],["dc.date.issued","2014"],["dc.description.abstract","Context. Observations of secondary eclipses of hot Jupiters allow one to measure the dayside thermal emission from the planets\\’ atmospheres. The combination of ground-based near-infrared observations and space-based observations at longer wavelengths constrains the atmospheric temperature structure and chemical composition. Aims. This work aims at detecting the thermal emission of WASP-5b, a highly irradiated dense hot Jupiter orbiting a G4V star every 1.6 days, in the J, H and K near-infrared photometric bands. The spectral energy distribution is used to constrain the temperature-pressure profile and to study the energy budget of WASP-5b. Methods. We observed two secondary-eclipse events of WASP-5b in the J, H, K bands simultaneously using the GROND instrument on the MPG/ESO 2.2 m telescope. The telescope was in nodding mode for the first observation and in staring mode for the second observation. The occultation light curves were modeled to obtain the flux ratios in each band, which were then compared with atmospheric models. Results. Thermal emission of WASP-5b is detected in the J and K bands in staring mode. The retrieved planet-to-star flux ratios are 0.168-0.052+0.050% in the J band and 0.269 ± 0.062% in the K band, corresponding to brightness temperatures of 2996-261+212 K and 2890-269+246 K, respectively. No thermal emission is detected in the H band, with a 3σ upper limit of 0.166% on the planet-to-star flux ratio, corresponding to a maximum temperature of 2779 K. On the whole, our J, H, K results can be explained by a roughly isothermal temperature profile of ~2700 K in the deep layers of the planetary dayside atmosphere that are probed at these wavelengths. Together with Spitzer observations, which probe higher layers that are found to be at ~1900 K, a temperature inversion is ruled out in the range of pressures probed by the combined data set. While an oxygen-rich model is unable to explain all the data, a carbon-rich model provides a reasonable fit but violates energy balance. The nodding-mode observation was not used for the analysis because of unremovable systematics. Our experience reconfirms that of previous authors: staring-mode observations are better suited for exoplanet observations than nodding-mode observations."],["dc.format.extent","12"],["dc.identifier.doi","10.1051/0004-6361/201321804"],["dc.identifier.fs","609739"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10915"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58145"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","Ground-based detection of the near-infrared emission from the dayside of WASP-5b"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A8"],["dc.bibliographiccitation.journal","Astronomy & Astrophysics"],["dc.bibliographiccitation.volume","567"],["dc.contributor.author","Chen, G."],["dc.contributor.author","van Boekel, R."],["dc.contributor.author","Wang, H."],["dc.contributor.author","Nikolov, N."],["dc.contributor.author","Seemann, U."],["dc.contributor.author","Henning, Th."],["dc.date.accessioned","2019-07-09T11:40:19Z"],["dc.date.available","2019-07-09T11:40:19Z"],["dc.date.issued","2014"],["dc.description.abstract","Aims. We aim to construct a spectral energy distribution (SED) for the emission from the dayside atmosphere of the hot Jupiter WASP-46b and to investigate its energy budget. Methods. We observed a secondary eclipse of WASP-46b simultaneously in the g′r′i′z′JHK bands using the GROND instrument on the MPG/ESO 2.2 m telescope. Eclipse depths of the acquired light curves were derived to infer the brightness temperatures at multibands that cover the SED peak. Results. We report the first detection of the thermal emission from the dayside of WASP-46b in the K band at 4.2σ level and tentative detections in the H (2.5σ) and J (2.3σ) bands, with flux ratios of 0.253 +0.063-0.060%, 0.194 ± 0.078%, and 0.129 ± 0.055%, respectively. The derived brightness temperatures (2306 +177-187 K, 2462 +245-302 K, and 2453 +198-258 K, respectively) are consistent with an isothermal temperature profile of 2386 K, which is significantly higher than the dayside-averaged equilibrium temperature, indicative of very poor heat redistribution efficiency. We also investigate the tentative detections in the g′r′i′ bands and the 3σ upper limit in the z′ band, which might indicate the existence of reflective clouds if these tentative detections do not arise from systematics."],["dc.format.extent","8"],["dc.identifier.doi","10.1051/0004-6361/201423795"],["dc.identifier.fs","609743"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10925"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58147"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.rights","Goescholar"],["dc.rights.access","openAccess"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","Observed spectral energy distribution of the thermal emission from the dayside of WASP-46b"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]