- ID:
- ivo://CDS.VizieR/J/A+A/615/A117
- Title:
- 55 Cnc geocoronal emission lines template
- Short Name:
- J/A+A/615/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The high-energy X-ray to ultraviolet (XUV) irradiation of close-in planets by their host star influences their evolution and might be responsible for the existence of a population of ultra-short period planets eroded to their bare core. In orbit around a bright, nearby G-type star, the super-Earth 55 Cnc e offers the possibility to address these issues through transit observations at UV wavelengths. We used the Hubble Space Telescope to observe the transit in the far-ultraviolet (FUV) over three epochs in April 2016, January 2017, and February 2017. Together, these observations cover nearly half of the orbital trajectory in between the two quadratures, and reveal significant short- and long-term variability in 55 Cnc chromospheric emission lines. In the last two epochs, we detected a larger flux in the CIII, SiIII, and SiIV lines after the planet passed the approaching quadrature, followed by a flux decrease in the SiIV doublet. In the second epoch these variations are contemporaneous with flux decreases in the SiII and CII doublet. All epochs show flux decreases in the NV doublet as well, albeit at different orbital phases. These flux decreases are consistent with absorption from optically thin clouds of gas, are mostly localized at low and redshifted radial velocities in the star rest frame, and occur preferentially before and during the planet transit. These three points make it unlikely that the variations are purely stellar in origin, yet we show that the occulting material is also unlikely to originate from the planet. We thus tentatively propose that the motion of 55 Cnc e at the fringes of the stellar corona leads to the formation of a cool coronal rain. The inhomogeneity and temporal evolution of the stellar corona would be responsible for the differences between the three visits. Additional variations are detected in the CII doublet in the first epoch and in the OI triplet in all epochs with a different behavior that points toward intrinsic stellar variability. Further observations at FUV wavelengths are required to disentangle definitively between star-planet interactions in the 55 Cnc system and the activity of the star.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/408/181
- Title:
- CN2002ch UBVRI and ugriz light curves
- Short Name:
- J/MNRAS/408/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric and spectroscopic observations of an unusual luminous blue variable (LBV) in NGC 3432, covering three major outbursts in 2008 October, 2009 April and 2009 November. Previously, this star experienced an outburst also in 2000 (known as SN 2000ch). During outbursts the star reached an absolute magnitude between -12.1 and -12.8. Its spectrum showed H, HeI and FeII lines with P-Cygni profiles during and soon after the eruptive phases, while only intermediate-width lines in pure emission (including HeII {lambda}4686) were visible during quiescence. The fast-evolving light curve soon after the outbursts, the quasi-modulated light curve, the peak magnitude and the overall spectral properties are consistent with multiple episodes of variability of an extremely active LBV. However, the widths of the spectral lines indicate unusually high wind velocities (1500-2800km/s), similar to those observed in Wolf-Rayet stars. Although modulated light curves are typical of LBVs during the S-Dor variability phase, the luminous maxima and the high frequency of outbursts are unexpected in S-Dor variables.
- ID:
- ivo://CDS.VizieR/J/MNRAS/390/1733
- Title:
- CN column densities and excitation temperatures
- Short Name:
- J/MNRAS/390/1733
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse abundances and rotational temperatures of the interstellar CN molecule. We have calculated the column densities and excitation temperatures of the molecule along 73 lines of sight basing on our original measurements of the B^2^{SIGMA}^+^-X^2^{SIGMA}^+^(0,0) vibrational band recorded in high signal-to-noise ratio spectra and also for 88 directions based on measurements already available in literature. We compare the column densities obtained from different bands of CN molecule available to ground-based instruments. The obtained excitation temperatures in the analysed directions show always an excess over the cosmic microwave background radiation (CMBR) temperature.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A1
- Title:
- 55 Cnc radial velocities and photometry
- Short Name:
- J/A+A/619/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orbiting a bright, nearby star the 55 Cnc system offers a rare opportunity to study a multiplanet system that has a wide range of planetary masses and orbital distances. Using two decades of photometry and spectroscopy data, we have measured the rotation of the host star and its solar-like magnetic cycle. Accounting for this cycle in our velocimetric analysis of the system allows us to revise the properties of the outermost giant planet and its four planetary companions. The innermost planet 55 Cnc e is an unusually close-in super-Earth, whose transits have allowed for detailed follow-up studies. Recent observations favor the presence of a substantial atmosphere yet its composition, and the nature of the planet, remain unknown. We combined our derived planet mass (Mp=8.0+/-0.3M_{Earth}_) with refined measurement of its optical radius derived from HST/STIS observations (Rp=1.88+/-0.03R_{Earth}_ over 530-750nm) to revise the density of 55 Cnc e (rho=6.7+/-0.4g/cm^3^). Based on these revised properties we have characterized possible interiors of 55 Cnc e using a generalized Bayesian model. We confirm that the planet is likely surrounded by a heavyweight atmosphere, contributing a few percents of the planet radius. While we cannot exclude the presence of a water layer underneath the atmosphere, this scenario is unlikely given the observations of the planet across the entire spectrum and its strong irradiation. Follow-up observations of the system in photometry and in spectroscopy over different time-scales are needed to further investigate the nature and origin of this iconic super-Earth.
- ID:
- ivo://CDS.VizieR/J/A+A/319/235
- Title:
- CN in circumstellar envelopes survey
- Short Name:
- J/A+A/319/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We list in Table 1 the observed stars together with some of their characteristics. Distances, expansion velocities, mass loss rates, and spectral types are taken from the compilations of Bujarrabal et al. (1994) <J/A+A/285/247> and Loup et al. (1993A&AS...99..291). The sample includes C-rich and O-rich objects, some S-stars, a few proto-PN, and a young PN (NGC7027). See paper for more details. In Table 2, we give some of the observational parameters. A_low_ and A_high_ refer to the integrated intensity of the low-frequency and high-frequency fine-structure groups. The intrinsic intensity ratios, R=A_high_/A_low_, are R(1-0)=2 and R(2-1)=1.8. In principle, the observation of several components with different intrinsic strengths allows an estimate of the line optical depth, and the value of R gives an estimate of the envelope thickness.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A28
- Title:
- 3C 294 NIR images and optical spectra
- Short Name:
- J/A+A/628/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High redshift radio galaxies are among the most massive galaxies at their redshift, are often found in the centers of proto-clusters of galaxies, and are expected to evolve into the present day massive central cluster galaxies. Thus they are a useful tool to explore structure formation in the young Universe. 3C 294 is a powerful FR II type radio galaxy at z=1.786. Past studies have identified a clumpy structure, possibly indicative of a merging system, as well as tentative evidence that 3C 294 hosts a dual AGN. Due to its proximity to a bright star, it was subject to various adaptive optics imaging studies. In order to distinguish between the various scenarios for 3C 294 we performed deep high-resolution adaptive optics imaging and optical spectroscopy of 3C 294 with the Large Binocular Telescope. We resolve the 3C 294 system into three distinct components separated by a few tenths of an arcsecond on our images. One is compact, the other two are extended, all appear to be non-stellar. The nature of each component is unclear. The latter could be a galaxy with an internal absorption feature, a galaxy merger or two galaxies at different redshifts. We can now uniquely associate the radio source of 3C 294 with one of the extended components. Based on our spectroscopy, we determined a redshift of z=1.784+/-0.001, which is similar to the one previously cited. In addition we found a previously unreported emission line at lambda 6749.4{AA} in our spectra. It is not clear that it originates from 3C 294. It could be the Ne [IV] doublet lambda 2424/2426{AA} at z=1.783, or belong to the compact component at a redshift of z~4.56. We thus can not unambiguously determine whether 3C 294 hosts a dual AGN or a projected pair of AGNs.
- ID:
- ivo://CDS.VizieR/J/A+A/353/528
- Title:
- CNO abundances in carbon stars
- Short Name:
- J/A+A/353/528
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The lines of ^12^CO, ^12^C^12^C, and ^12^CN used in the analysis are listed in the table. The stars analyzed here are TX Psc, V Aql, and BL Ori, and the lines selected for the analysis are listed for each star. The data given in the table are the wavenumber, gf-value, and the lower excitation potential of each selected line, together with the observed equivalent width.
- ID:
- ivo://CDS.VizieR/J/PASJ/57/65
- Title:
- CNO abundances of solar-type stars
- Short Name:
- J/PASJ/57/65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determined the C, N, and O abundances of 160 nearby F, G, and K dwarfs and subgiants by using spectra obtained with the HIDES spectrograph at Okayama Astrophysical Observatory, with the purposes of (1) establishing the runs of [C/Fe], [N/Fe], and [O/Fe] for these galactic disk stars in the metallicity range of -1<~[Fe/H]~<+0.4, (2) searching for any difference in the CNO abundances of planet-host stars as compared to non-planet-host stars, and (3) examining the consistency of the abundances derived from different lines to check the validity of the analysis. The non-LTE effect on the abundance determination was taken into consideration based on our extensive statistical-equilibrium calculations.
- ID:
- ivo://CDS.VizieR/J/ApJS/102/289
- Title:
- CNOC cluster redshift survey catalogs. II.
- Short Name:
- J/ApJS/102/289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photometric and redshift catalog of galaxies in the field of the rich galaxy cluster Abell 2390 (z=0.228) is presented as part of the Canadian Network for Observation Cosmology (CNOC) cluster redshift survey carried out at the Canada-France-Hawaii Telescope (CFHT) using the MOS imaging multiobject spectrograph. Using five separate fields, the imaging and spectroscopic observations cover a strip of approximately 7.3'x43.2', centered on the cluster. Redshifts for 327 galaxies, primarily ranging in magnitude from r=17 to 22, were obtained. The data set is also presented graphically in several forms. The magnitude, geometric, and color selection functions for the redshift sample are discussed and presented.
- ID:
- ivo://CDS.VizieR/J/ApJS/113/1
- Title:
- CNOC cluster redshift survey catalogs. III.
- Short Name:
- J/ApJS/113/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photometric and redshift catalog of galaxies in the field of two rich galaxy clusters, MS 1621.5+2640 (z=0.4275) and MS 0302.7+1658 (z=0.4245), is presented as part of the Canadian Network for Observation Cosmology (CNOC) Cluster Redshift Survey carried out at the Canada-France-Hawaii Telescope (CFHT) using the MOS imaging multiobject spectrograph. The imaging and spectroscopic observations cover strips cantered on each cluster of approximately 23.3'x9.0', and 7.9'x9.0', for MS 1621.5+2640 and MS 0302.7+1658, respectively. Redshifts for 371 galaxies, primarily ranging in magnitude from r=20 to 22, were obtained. The data set is also presented graphically in several forms. The magnitude, color, and geometric selection functions for the redshift sample are presented and discussed.
