- ID:
- ivo://CDS.VizieR/J/A+A/641/A33
- Title:
- EX Lup SPHERE and SINFONI images
- Short Name:
- J/A+A/641/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- EX Lup is a well-studied T Tauri star that represents the prototype of young eruptive stars EXors. These are characterized by repetitive outbursts due to enhanced accretion from the circumstellar disk onto the star. In this paper we analyze new adaptive optics imaging and spectroscopic observations to study EX Lup and its circumstellar environment in near-infrared in its quiescent phase. We aim at providing a comprehensive understanding of the circumstellar environment around EX Lup in quiescence that builds upon the vast literature data. We observed EX Lup in quiescence with the high contrast imager SPHERE/IRDIS in the dual-beam polarimetric imaging mode to resolve the circumstellar environment in near-infrared scattered light. We complemented these data with earlier SINFONI spectroscopy, also taken in quiescence. Results.We resolve for the first time in scattered light a compact feature around EX Lup azimuthally extending from ~280{deg} to ~360{deg}, and radially extending from 0.3" to 0.55" in the plane of the disk. We explore two different scenarios for the detected emission. The first one accounts for the emission as coming from the brightened walls of the cavity excavated by the outflow whose presence was suggested by ALMA observations in the J=3-2 line of ^12^CO. The second one accounts for the emission as coming from an inclined disk. In this latter case we detect for the first time a more extended circumstellar disk in scattered light, which shows that a region between 10 and 30au is depleted of um-size grains. We compare the J-, H- and K- band spectra obtained with SINFONI in quiescence with the spectra taken during the outburst, showing that all the emission lines were due to the episodic accretion event. Based on the morphology analysis we favour the scenario in which the scattered light is coming from a circumstellar disk rather than the outflow around EX Lup. We analyze the origin of the observed feature either as coming from a continuous circumstellar disk with a cavity, or from the illuminated wall of the outer disk or from a shadowed disk. Moreover, we discuss what is the origin of the m-size grains depleted region, exploring the possibility that a sub-stellar companion may be the cause of it.
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5812. EXMS catalog
- ID:
- ivo://CDS.VizieR/J/A+AS/134/287
- Title:
- EXMS catalog
- Short Name:
- J/A+AS/134/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of X-ray sources observed during slew maneuvers by the Medium Energy Detector Array onboard the EXOSAT Observatory. The EXOSAT Medium Energy slew-survey catalog (EXMS) provides a unique record of the 1-8keV X-ray sky between 1983 and 1986. 98% of the sky was observed, with 85% receiving an exposure of >60s. 1210 sources were detected. By comparing these source positions with other catalogs, identifications are given for 992 detections (82% of the sample). These identifications consist of 250 distinct objects, including 95 different X-ray binary systems, and 14 different AGN. A further 58 detections have multiple candidates, while 160 detections remain unidentified. Collimator transmission corrected 1-8keV count rates are given for the identified sources, together with raw count rates for the other detections. The construction of the EXMS and the checks performed to ensure the validity of the derived source properties are discussed. A publically available version of this catalog is maintained on the EXOSAT database and archive system (telnet://xrayxosat.estec.esa.nl).
- ID:
- ivo://CDS.VizieR/J/A+A/639/A11
- Title:
- Exocomets. A Spectroscopic Survey
- Short Name:
- J/A+A/639/A11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While exoplanets are now routinely detected, the detection of small bodies in extrasolar systems remains challenging. Since the discovery of sporadic events, which are interpreted to be exocomets (falling evaporating bodies) around beta Pic in the early 1980s, Monly 20 stars have been reported to host exocomet-like events. We aim to expand the sample of known exocomet-host stars, as well as to monitor the hot-gas environment around stars with previously known exocometary activity. We have obtained high-resolution optical spectra of a heterogeneous sample of 117 main-sequence stars in the spectral type range from B8 to G8. The data were collected in 14 observing campaigns over the course of two years from both hemispheres. We analysed the CaII K&H and NaI D lines in order to search for non-photospheric absorptions that originated in the circumstellar environment and for variable events that could be caused by the outgassing of exocomet-like bodies. We detected non-photospheric absorptions towards 50% of the sample, thus attributing a circumstellar origin to half of the detections (i.e. 26% of the sample). Hot circumstellar gas was detected in the metallic lines inspected via narrow stable absorptions and/or variable blue- and red-shifted absorption events. Such variable events were found in 18 stars in the CaII and/or NaI lines; six of them are reported in the context of this work for the first time. In some cases, the variations we report in the CaII K line are similar to those observed in beta^L Pic. While we do not find a significant trend in the age or location of the stars, we do find that the probability of finding CS gas in stars with larger vsini is higher. We also find a weak trend with the presence of near-infrared excess and with anomalous (lambda Boo-like) abundances, but this would require confirmation by expanding the sample.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1828
- Title:
- ExoMol line list for HCN and HNC
- Short Name:
- J/MNRAS/437/1828
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A revised rotation-vibration line list for the combined hydrogen cynanide (HCN)/hydrogen isocyanide (HNC) system is presented. The line list uses ab initio transition intensities calculated previously (Harris et al., 2002ApJ...578..657H) and extensive datasets of recently measured experimental energy levels. The resulting line list has significantly more accurate wavelengths than previous ones for these systems. An improved value for the separation between HCN and HNC is adopted leading to an approximately 25% lower predicted thermal population of HNC as a function of temperature in the key 2000 to 3000K region. Temperature-dependent partition functions and equilibrium constant are presented. The line lists are validated by comparison with laboratory spectra and are presented in full as supplementary data to the article and at www.exomol.com.
- ID:
- ivo://CDS.VizieR/J/MNRAS/466/1363
- Title:
- ExoMol line list for H_2_^18^O and H_2_^17^O
- Short Name:
- J/MNRAS/466/1363
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hot line lists for two isotopologues of water, H_2_^18^O and H_2_^17^O, are presented. The calculations employ newly constructed potential energy surfaces (PES), which take advantage of a novel method for using the large set of experimental energy levels for H_2_^16^O to give high-quality predictions for H_2_^18^O and H_2_^17^O. This procedure greatly extends the energy range for which a PES can be accurately determined, allowing an accurate prediction of higher lying energy levels than are currently known from direct laboratory measurements. This PES is combined with a high-accuracy, ab initio dipole moment surface of water in the computation of all energy levels, transition frequencies and associated Einstein A coefficients for states with rotational excitation up to J=50 and energies up to 30000cm^-1^. The resulting HotWat78 line lists complement the well-used BT2 H_2_^16^O line list.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/4063
- Title:
- ExoMol line list for H2S AYT2
- Short Name:
- J/MNRAS/460/4063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents the AYT2 line list: a comprehensive list of 115 million ^1^H_2_^32^S vibration-rotation transitions computed using an empirically adjusted potential energy surface and an ab initio dipole moment surface. The line list gives complete coverage up to 11000cm^-1^ (wavelengths longer than 0.91um) for temperatures up to 2000K. Room temperature spectra can be simulated up to 20000cm^-1^ (0.5um) but the predictions at visible wavelengths are less reliable. AYT2 is made available in electronic form as supplementary data to this paper at www.exomol.com.
5817. ExoMol line list for KCl
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/1821
- Title:
- ExoMol line list for KCl
- Short Name:
- J/MNRAS/442/1821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate rotation-vibration line lists for two molecules, NaCl and KCl, in their ground electronic states are presented. These line lists are suitable for temperatures relevant to exoplanetary atmospheres and cool stars (up to 3000K). Isotopologues ^23^Na^35^Cl, ^23^Na^37^Cl, ^39^K^35^Cl, ^39^K^37^Cl, ^41^K^35^Cl and ^41^K^37^Cl are considered. Laboratory data were used to refine ab initio potential energy curves in order to compute accurate ro-vibrational energy levels. Einstein A coefficients are generated using newly determined ab initio dipole moment curves calculated using the CCSD(T) method. New Dunham Yij constants for KCl are generated by a re-analysis of a published Fourier transform infrared emission spectra. Partition functions plus full line lists of ro-vibration transitions are made available in an electronic form here and at www.exomol.com.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/1383
- Title:
- ExoMol line list for phosphorus nitride (PN)
- Short Name:
- J/MNRAS/445/1383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate rotational-vibrational line lists for two isotopologues of PN in their ground electronic states are computed. The line lists are produced using an empirical potential energy curve obtained by fitting to the experimental transition frequencies available in the literature in conjunction with an accurate, high level ab initio dipole moment curve. In these calculations the programs DPotFit and LEVEL 8.0 were used. The new line lists reproduce the experimental wavenumbers with a root-mean-square error of 0.004cm^-1^. The line lists cover the frequency range 0-51000cm^-1^, contain almost 700000 lines each and extend up to a maximum vibrational level of v=66 and a maximum rotational level of J=357. They should be applicable for a large range of temperature up to, at least, 5000K. These new line lists are used to simulate spectra for PN at a range of temperatures and are deposited in the Strasbourg data centre. This work is part of the ExoMol project (2012MNRAS.425...21T).
5819. ExoMol line lists. AlH
- ID:
- ivo://CDS.VizieR/J/MNRAS/479/1401
- Title:
- ExoMol line lists. AlH
- Short Name:
- J/MNRAS/479/1401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new line list for AlH is produced. The WYLLoT line list spans two electronic states X^1^{SIGMA}^1^ and A^1^{PI}. A diabatic model is used to model the shallow potential energy curve of the A^1^{PI} state, which has a strong pre-dissociative character with only two bound vibrational states. Both potential energy curves are empirical and were obtained by fitting to experimentally derived energies of the X^1^{SIGMA}^1^ and A^1^{PI} electronic states using the diatomic nuclear motion codes Level and Duo. High temperature line lists plus partition functions and lifetimes for three isotopologues ^27^AlH, ^27^AlD and ^26^AlH were generated using ab initio dipole moments obtained with the MRCI/aug-cc-pV5Z level of theory. The line lists cover both the X-X and A-X systems and are made available in electronic form at the CDS and ExoMol databases.
5820. ExoMol line lists. CH3Cl
- ID:
- ivo://CDS.VizieR/J/MNRAS/479/3002
- Title:
- ExoMol line lists. CH3Cl
- Short Name:
- J/MNRAS/479/3002
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Comprehensive rotation-vibration line lists in the form of temperature-dependent super-lines are presented for the two main isotopologues of methyl chloride, ^12^CH_3_^35^Cl and ^12^CH_3_^37^Cl. The line lists, OYT-35 and OYT-37, are suitable for temperatures up to T=1200K and consider transitions with rotational excitation up to J=85 the wavenumber range 0-6400cm^-1^ (wavelengths {lambda}>1.56um). Over 166 billion transitions between 10.2 million energy levels have been calculated variationally for each line list using a new empirically refined potential energy surface, determined by refining to 739 experimentally derived energy levels up to J=5, and an established ab initio dipole moment surface. The OYT line lists show excellent agreement with newly measured high-temperature infrared absorption cross-sections, reproducing both strong and weak intensity features across the spectrum. The line lists are also available from the ExoMol database.