- ID:
- ivo://CDS.VizieR/J/A+A/632/A57
- Title:
- G328.2551-0.5321 spectra
- Short Name:
- J/A+A/632/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical hot cores are rich in molecular emission, and they show a high abundance of complex organic molecules (COMs). The emergence of molecular complexity that is represented by COMs, in particular, is poorly constrained in the early evolution of hot cores. We put observational constraints on the physical location of COMs in a resolved high-mass protostellar envelope associated with the G328.2551-0.5321 clump. The protostar is single down to 400au scales and we resolved the envelope structure down to this scale. High angular resolution observations using the Atacama Large Millimeter Array allowed us to resolve the structure of the inner envelope and pin down the emission region of COMs. We use local thermodynamic equilibrium modelling of the available 7.5GHz bandwidth around 345GHz to identify the COMs towards two accretion shocks and a selected position representing the bulk emission of the inner envelope. We quantitatively discuss the derived molecular column densities and abundances towards these positions, and use our line identification to qualitatively compare this to the emission of COMs seen towards the central position, corresponding to the protostar and its accretion disk. We detect emission from 10 COMs, and identify a line of deuterated water (HDO). In addition to methanol (CH_3_OH), methyl formate (CH_3_OCHO) and formamide (HC(O)NH_2_) have the most extended emission. Together with HDO, these molecules are found to be associated with both the accretion shocks and the inner envelope, which has a moderate temperature of Tkin~110K. We find a significant difference in the distribution of COMs. O-bearing COMs, such as ethanol, acetone, and ethylene glycol are almost exclusively found and show a higher abundance towards the accretion shocks with Tkin~180K. Whereas N-bearing COMs with a CN group, such as vinyl and ethyl cyanide peak on the central position, thus the protostar and the accretion disk. The molecular composition is similar towards the two shock positions, while it is significantly different towards the inner envelope, suggesting an increase in abundance of O-bearing COMs towards the accretion shocks. We present the first observational evidence for a large column density of COMs seen towards accretion shocks at the centrifugal barrier at the inner envelope. The overall molecular emission shows increased molecular abundances of COMs towards the accretion shocks compared to the inner envelope. The bulk of the gas from the inner envelope is still at a moderate temperature of Tkin~110K, and we find that the radiatively heated inner region is very compact (<1000au). Since the molecular composition is dominated by that of the accretion shocks and the radiatively heated hot inner region is very compact, we propose this source to be a precursor to a classical, radiatively heated hot core. By imaging the physical location of HDO, we find that it is consistent with an origin within the moderately heated inner envelope, suggesting that it originates from sublimation of ice from the grain surface and its destruction in the vicinity of the heating source has not been efficient yet.
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- ID:
- ivo://CDS.VizieR/J/A+A/589/A62
- Title:
- GTC transit light curves of CoRoT-29b
- Short Name:
- J/A+A/589/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The launch of the exoplanet space missions obtaining exquisite photometry from space has resulted in the discovery of thousands of planetary systems with very different physical properties and architectures. Among them, the exoplanet CoRoT-29b was identified in the light curves the mission obtained in summer 2011, and presented an asymmetric transit light curve, which was tentatively explained via the effects of gravity darkening. Here we use the OSIRIS spectrograph at the 10-m GTC telescope to measure with high precision the transit light curve of CoRoT-29b to characterize the reported asymmetry in its transit shape. To this end, using the OSIRIS spectrograph at the 10-m GTC telescope, we perform spectro-photometric differential observations, which allow us to both calculate a high-accuracy photometric light curve, and a study of the color-dependence of the transit. After careful data analysis, we find that there is no asymmetry in the transit of CoRoT-29b, in either of the two observed transits, separated by one calendar year. Due to the relative faintness of the star, we do not reach the precision necessary to perform transmission spectroscopy of its atmosphere, but we see no signs of color-dependency of the transit depth or duration. We conclude that the previously reported asymmetry is a time-dependent phenomenon which did not occur in more recent epochs, or possible instrumental effects in the discovery data need to be reconsidered.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A172
- Title:
- GTC transit light curves of HAT-P-11b
- Short Name:
- J/A+A/622/A172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected using ground- or space-based telescopes. However, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this phenomena is key to our correct interpretation of exoplanet atmospheric properties. We obtained Gran Telescopio Canarias (GTC) long-slit optical spectroscopy of two transits of HAT-P-11b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) on August 30, 2016 and September 25, 2017. By fitting both transits together, we find a slope in the transmission spectrum showing an increase of the planetary radius towards blue wavelengths. Closer inspection of the transmission spectrum of the individual data sets reveals that the first transit presents this slope while the transmission spectrum of the second data set is flat. Additionally, we detect hints of Na absorption on the first night, but not on the second. We conclude that the transmission spectrum slope and Na absorption excess found in the first transit observation are caused by unocculted stellar spots. Modeling the contribution of unocculted spots to reproduce the results of the first night we find a spot filling factor of delta=0.62^+0.20^_-0.17_ and a spot-to-photosphere temperature difference of {Delta}T=429^+184^_-299_K.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A65
- Title:
- GTC transit light curves of HAT-P-32b
- Short Name:
- J/A+A/594/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the hot Jupiter HAT-P-32b (also known as HAT-P-32Ab) to determine its optical transmission spectrum by measuring the wavelength-dependent, planet-to-star radius ratios in the region between 518-918nm. We used the OSIRIS instrument at the Gran Telescopio CANARIAS (GTC) in long-slit spectroscopy mode, placing HAT-P-32 and a reference star in the same slit and obtaining a time series of spectra covering two transit events. Using the best quality data set, we were able to yield 20 narrowband transit light curves, with each passband spanning a 20nm wide interval. After removal of all systematic noise signals and light curve modeling, the uncertainties for the resulting radius ratios lie between 337 and 972ppm. The radius ratios show little variation with wavelength, suggesting a high altitude cloud layer masking any atmospheric features. Alternatively, a strong depletion in alkali metals or a much smaller than expected planetary atmospheric scale height could be responsible for the lack of atmospheric features. Our result of a flat transmission spectrum is consistent with a previous ground-based study of the optical spectrum of this planet. This agreement between independent results demonstrates that ground-based measurements of exoplanet atmospheres can give reliable and reproducible results despite the fact that the data often is heavily affected by systematic noise as long as the noise source is well understood and properly corrected.
- ID:
- ivo://CDS.VizieR/J/A+A/616/A145
- Title:
- GTC transit light curves of WASP-127b
- Short Name:
- J/A+A/616/A145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanets with relatively clear atmospheres are prime targets for detailed studies of chemical compositions and abundances in their atmospheres. Alkali metals have been long suggested to exhibit broad wings due to pressure broadening, but most of the alkali detections only show very narrow absorption cores, probably due to the presence of clouds. Here we report the strong detection of the pressure-broadened spectral profiles of Na, K, and Li absorption in the atmosphere of the super-Neptune WASP-127b, at 5.0{sigma}, 4.1{sigma}, and 3.4{sigma}, respectively. We performed a spectral retrieval modeling on the high-quality optical transmission spectrum newly acquired with the 10.4m Gran Telescopio Canarias (GTC), in combination with the re-analyzed optical transmission spectrum obtained with the 2.5m Nordic Optical Telescope (NOT). By assuming a patchy cloudy model, we retrieved the abundances of Na, K, and Li, which are super-solar at 3.7{sigma} for K and 5.1{sigma} for Li (and only 1.8{sigma} for Na). We constrained the presence of haze coverage to be around 52%. We also found a hint of water absorption, but cannot constrain it with the global retrieval due to larger uncertainties in the probed wavelengths. WASP-127b will be extremely valuable for atmospheric characterization in the era of James Webb space telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/600/L11
- Title:
- GTC transit light curves of WASP-52b
- Short Name:
- J/A+A/600/L11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522nm to 903nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is stringently ruled out. By assessing the absorption depths of sodium in various bin widths, we find that temperature increases towards lower atmospheric pressure levels, with a positive temperature gradient of 0.88+/-0.65K/km , possibly indicative of upper atmospheric heating and a temperature inversion.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A158
- Title:
- GTC transit light curves of WASP-69b
- Short Name:
- J/A+A/641/A158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the major atmospheric features in exoplanet atmospheres, detectable both from ground- and space-based facilities, is Rayleigh scattering. In hydrogen-dominated planetary atmospheres Rayleigh scattering causes the measured planetary radius to increase towards blue wavelengths in the optical range. We obtained a spectrophotometic time series of one transit of the Saturn-mass planet WASP-69b using the OSIRIS instrument at the Gran Telescopio Canarias. From the data we construct 19 spectroscopic transit light curves representing 20nm wide wavelength bins spanning from 515nm-905nm. We derive the transit depth for each curve individually by fitting an analytical model together with a Gaussian Processes to account for systematic noise in the light curves. We find that the transit depth increases towards bluer wavelengths, indicative of a larger effective planet radius. Our results are consistent with space-based measurements obtained in the near infrared using the Hubble Space telescope, which show a compatible slope of the transmission spectrum. We discuss the origin of the detected slope and argue between two possible scenarios: a Rayleigh scattering detection originating in the planet's atmosphere or a stellar activity induced signal from the host star.
- ID:
- ivo://CDS.VizieR/J/A+A/605/A114
- Title:
- GTC transit light curves of WASP-48b
- Short Name:
- J/A+A/605/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained long-slit optical spectroscopy of one transit of WASP-48b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph. We report a relatively flat transmission spectrum (wavelength coverage from 530 nm to 905 nm) for WASP-48b with no statistical significant detection of atmospheric species, although the theoretical models that fit the data more closely include TiO and VO.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A138
- Title:
- G09v1.97 CO and H2O datacubes
- Short Name:
- J/A+A/624/A138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Atacama Large Millimeter/submillimeter Array (ALMA), we report high angular-resolution observations of the redshift z=3.63 galaxy H-ATLAS J083051.0+013224 (G09v1.97), one of the most luminous strongly lensed galaxies discovered by the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). We present 0.2"-0.4" resolution images of the rest-frame 188 and 419um dust continuum and the CO(6-5), H_2_O(2_11_-2_02_), and Jup=2H_2_O^+^ line emission. We also report the detection of H_2_^18^O(2_11_-2_02_) in this source. The dust continuum and molecular gas emission are resolved into a nearly complete ~1.5" diameter Einstein ring plus a weaker image in the center, which is caused by a special dual deflector lensing configuration. The observed line profiles of the CO(6-5), H_2_O(2_11_-2_02_), and Jup=2H_2_O^+^ lines are strikingly similar. In the source plane, we reconstruct the dust continuum images and the spectral cubes of the CO, H_2_O, and H_2_O^+^ line emission at sub-kiloparsec scales. The reconstructed dust emission in the source plane is dominated by a compact disk with an effective radius of 0.7+/-0.1kpc plus an overlapping extended disk with a radius twice as large. While the average magnification for the dust continuum is {mu}~10-11, the magnification of the line emission varies from 5 to 22 across different velocity components. The line emission of CO(6-5), H_2_O(2_11_-2_02_), and H_2_O^+^ have similar spatial and kinematic distributions. The molecular gas and dust content reveal that G09v1.97 is a gas-rich major merger in its pre-coalescence phase, with a total molecular gas mass of ~10^11^M_{sun}_. Both of the merging companions are intrinsically ultra-luminous infrared galaxies (ULIRGs) with infrared luminosities LIR reaching 4x10^12^L_{sun}_, and the total LIR of G09v1.97 is (1.4+/-0.7)x10^13^L_{sun}_. The approaching southern galaxy (dominating from V=-400 to -150km/s relative to the systemic velocity) shows no obvious kinematic structure with a semi-major half-light radius of a_s_=0.4kpc, while the receding galaxy (0 to 350km/s) resembles an a_s_=1.2kpc rotating disk. The two galaxies are separated by a projected distance of 1.3kpc, bridged by weak line emission (-150 to 0km/s) that is co-spatially located with the cold dust emission peak, suggesting a large amount of cold interstellar medium (ISM) in the interacting region. As one of the most luminous star-forming dusty high-redshift galaxies, G09v1.97 is an exceptional source for understanding the ISM in gas-rich starbursting major merging systems at high redshift.
- ID:
- ivo://CDS.VizieR/J/A+A/598/A26
- Title:
- HADES RV Programme with HARPS-N at TNG. II.
- Short Name:
- J/A+A/598/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of exoplanets around low-mass stars is still not well understood. Such stars, however, present an excellent opportunity for reaching down to the rocky and habitable planet domains. The number of current detections used for statistical purposes remains relatively modest and different surveys, using both photometry and precise radial velocities, are searching for planets around M dwarfs. Our HARPS-N red dwarf exoplanet survey is aimed at the detection of new planets around a sample of 78 selected stars, together with the subsequent characterization of their activity properties. Here we investigate the survey performance and strategy. From 2700 observed spectra, we compare the radial velocity determinations of the HARPS-N DRS pipeline and the HARPS-TERRA code, calculate the mean activity jitter level, evaluate the planet detection expectations, and address the general question of how to define the strategy of spectroscopic surveys in order to be most efficient in the detection of planets. We find that the HARPS-TERRA radial velocities show less scatter and we calculate a mean activity jitter of 2.3m/s for our sample. For a general radial velocity survey with limited observing time, the number of observations per star is key for the detection efficiency. In the case of an early M-type target sample, we conclude that approximately 50 observations per star with exposure times of 900s and precisions of approximately 1m/s maximizes the number of planet detections.
