- ID:
- ivo://CDS.VizieR/J/A+A/648/A110
- Title:
- HD142527 SPHERE polarimetric images
- Short Name:
- J/A+A/648/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision photometry and polarimetry based on visual and near-infrared imaging data for the protoplanetary disk surrounding the Herbig Ae/Be star HD 142527, with a strong focus on determining the light scattering parameters of the dust located at the surface of the large outer disk. We re-reduced existing polarimetric differential imaging data of HD 142527 in the VBB (735nm) and H-band (1625nm) from the ZIMPOL and IRDIS subinstruments of SPHERE at the VLT. With polarimetry and photometry based on reference star differential imaging (RDI), we were able to measure the linearly polarized intensity and the total intensity of the light scattered by the circumstellar disk with high precision. We used simple Monte Carlo simulations of multiple light scattering by the disk surface to derive constraints for three scattering parameters of the dust: the maximum polarization of the scattered light Pmax, the asymmetry parameter g, and the single-scattering albedo {omega}. We measure a reflected total intensity of 51.4+/-1.5mJy and 206+/-12mJy and a polarized intensity of 11.3+/-0.3mJy and 55.1+/-3.3mJy in the VBB and H-band, respectively. We also find in the visual range a degree of polarization that varies between 28% on the far side of the disk and 17% on the near side. In the H-band, the degree of polarization is consistently higher by about a factor of 1.2. The disk also shows a red color for the scattered light intensity and the polarized intensity, which are about twice as high in the near-infrared when compared to the visual. We determine with model calculations the scattering properties of the dust particles and find evidence for strong forward scattering (g {prop.to} 0.5-0.75), relatively low single-scattering albedo ({omega} {prop.to} 0.2-0.5), and high maximum polarization (Pmax {prop.to} 0.5-0.75) at the surface on the far side of the disk for both observed wavelengths. The optical parameters indicate the presence of large aggregate dust particles, which are necessary to explain the high maximum polarization, the strong forward-scattering nature of the dust, and the observed red disk color.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/830/30
- Title:
- HDS spectrum of nova V2659 Cyg (Nova Cyg 2014)
- Short Name:
- J/ApJ/830/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on high-dispersion spectroscopy results of a classical nova V2659 Cyg (Nova Cyg 2014) that are taken 33.05 days after the V-band maximum. The spectrum shows two distinct blueshifted absorption systems originating from H I, Fe II, Ca II, etc. The radial velocities of the absorption systems are -620km/s, and -1100 to -1500km/s. The higher velocity component corresponds to the P-Cygni absorption features frequently observed in low-resolution spectra. Much larger numbers of absorption lines are identified at the lower velocity. These mainly originate from neutral or singly ionized Fe-peak elements (Fe I, Ti II, Cr II, etc.). Based on the results of our spectroscopic observations, we discuss the structure of the ejecta of V2659 Cyg. We conclude that the low- and high-velocity components are likely to be produced by the outflow wind and the ballistic nova ejecta, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A68
- Title:
- HD 137496 system discovery
- Short Name:
- J/A+A/657/A68
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Most of the currently known planets are small worlds with radii between that of the Earth and Neptune. The characterization of planets in this regime shows a large diversity in compositions and system architectures, with distributions hinting at a multitude of formation and evolution scenarios. However, many planetary populations, such as high-density planets, are significantly under-sampled limiting our understanding on planet formation and evolution. NCORES is a large observing program conducted on the HARPS high-resolution spectrograph which aims to confirm the planetary status and to measure the masses of small transiting planetary candidates detected by transit photometry surveys in order to constrain their internal composition.Methods.Using photometry from the K2 satellite and radial velocities measured with the HARPS and CORALIE spectrographs, we search for planets around the bright (Vmag=10) and slightly evolved Sun-like star HD 137496. We precisely estimate the stellar parameters, M*=1.035+/-0.022M_{sun}_, R*= 1.587+/-0.028R_{sun}_, Teff=5799+/-61K,together with the chemical composition (e.g. [Fe/H]=-0.027+/-0.040dex) of the slightly evolved star. We detect two planets orbiting HD 137496. The inner planet, HD 137496 b, is a super-Mercury (an Earth-sized planet with the density of Mercury) with a mass of Mb=4.04+/-0.55M_{sun}_), a radius of Rb=1.31^+0.06^_-0.05_R_{sun}_ and a density of {rho}b=10.49^+2.08^_-1.82_g/cm^3^. From interior modeling analysis we find that the planet is composed mainly of iron, with the core representing over 70% of the planet's mass (Mcore/Mtotal=0.73^+0.11^_-0.12_). The outer planet, HD 137496 c, is an eccentric (e=0.477+/-0.004), long period (P=479.9^+1.0^_-1.1_days) giant planet (Mc*sinic=7.66+/-0.11M_{Jup}_) for which we do not detect a transit. HD 137496 b is one of the few super-Mercuries detected to date. The accurate characterization reported here enhances its role as a key target to better understand the formation and evolution of planetary systems. The detection of an eccentric long period giant companion also reinforces the link between the presence of small transiting inner planets and long period gas giants.
8074. HD 2685 TESS photometry
- ID:
- ivo://CDS.VizieR/J/A+A/625/A16
- Title:
- HD 2685 TESS photometry
- Short Name:
- J/A+A/625/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the confirmation of a transiting giant planet around the relatively hot (Teff=6801+/-56K) star HD 2685, whose transit signal was detected in Sector 1 data of NASA's TESS mission. We confirmed the planetary nature of the transit signal using Doppler velocimetric measurements with CHIRON, CORALIE, and FEROS, as well as using photometric data obtained with the Chilean-Hungarian Automated Telescope and the Las Cumbres Observatory. From the joint analysis of photometry and radial velocities, we derived the following parameters for HD 2685b: P=4.12688^+0.00005^_-0.00004_-days, e=0.091^+0.039^_-0.047_, M_P_=1.17+/-0.12M_J_, and R_P_=1.44+/-0.05R_J_. This system is a typical example of an inflated transiting hot Jupiter in a low-eccentricity orbit. Based on the apparent visual magnitude (V=9.6mag) of the host star, this is one of the brightest known stars hosting a transiting hot Jupiter, and it is a good example of the upcoming systems that will be detected by TESS during the two-year primary mission. This is also an excellent target for future ground- and space-based atmospheric characterization as well as a good candidate for measuring the projected spin-orbit misalignment angle through the Rossiter-McLaughlin effect.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A116
- Title:
- HD50138 time-dependent spectral variations
- Short Name:
- J/A+A/586/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B[e] stars are anomalous objects around which extended circumstellar matter is present. The observed properties of the central star are significantly affected by the surrounding material. Therefore, the use of standard synthetic spectra is disputable in this case and our capability to study these objects is limited. One of the possibilities is to analyse variations of the spectral features. Long-term spectroscopic observations are required for this, but are not found in the literature. For our study we choose the B[e] star HD 50138 of the FS CMa type because of the indication that this star is a post-main-sequence star, although still not highly evolved. Therefore, it can be a good object for testing evolutionary models. Currently, HD 50138 is the most extensively observed FS CMa star which makes it an ideal object for modelling. Our observations fill the gap in the available data. To describe the variability of HD 50138 we have monitored this star spectroscopically over the last twenty years. To search for the periodicity on short-term scales, series of night-to-night observations were also obtained.
- ID:
- ivo://CDS.VizieR/J/A+A/503/601
- Title:
- HD 17156 transit photometry & radial velocities
- Short Name:
- J/A+A/503/601
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To improve the parameters of the HD17156 system (peculiar due to the eccentric and long orbital period of its transiting planet) and constrain the presence of stellar companions. Photometric data were acquired for 4 transits, and high precision radial velocity measurements were simultaneously acquired with SARG at TNG for one transit. The template spectra of HD 17156 was used to derive effective temperature, gravity, and metallicity. A fit of the photometric and spectroscopic data was performed to measure the stellar and planetary radii, and the spin-orbit alignment. Planet orbital elements and ephemeris were derived from the fit. Near infrared adaptive optic images was acquired with ADOPT at TNG. We have found that the star has a radius of R_S_=1.44+/-0.03R_{sun}_ and the planet R_P_=1.02+/-0.08R_{jup}_ The transit ephemeris is T_c_=2454756.73134+/-0.00020+N*21.21663+/-0.00045 BJD. The analysis of the Rossiter-Mclaughlin effect shows that the system is spin orbit aligned with an angle Beta=4.8+/-5.3deg The analysis of high resolution images has not revealed any stellar companion with projected separation between 150 and 1000 AU from HD17156. Here we present the photometric data of the transits of HD 17156b.
8077. HD 80606 transits
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2233
- Title:
- HD 80606 transits
- Short Name:
- J/MNRAS/419/2233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of HD 80606 using the 10.4-m Gran Telescopio Canarias and the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) tunable filter imager. We acquired very high precision, narrow-band photometry in four bandpasses around the KI absorption feature during the 2010 January transit of HD 80606b and during out-of-transit observations conducted in 2010 January and April. We obtained differential photometric precisions of ~2.08x10^-4^ for the in-transit flux ratio measured at 769.91nm, which probes the KI line core.
8078. HD 185510 UBV photometry
- ID:
- ivo://CDS.VizieR/J/A+A/333/205
- Title:
- HD 185510 UBV photometry
- Short Name:
- J/A+A/333/205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBV photometry and moderate resolution H{alpha} spectrophotometry of the evolved binary system HD 185510 (sdB + K0 III), performed at Catania Astrophysical Observatory, is presented and discussed. The spectrophotometric data were collected in 1991, 1993, and 1994, while the photometric light curves were obtained in 1993, 1994 and 1995. From the B and V photometry we determine a new photometric rotational period of 26.23d, confirming the asynchronous rotation of the cool giant component. The spectroscopic data confirm the vsin i value of 15km/s measured by Fekel et al. (1993AJ....106.2370F) and clearly reveal a filled-in H{alpha} line with appreciable variations. The excess emission of the line, observed at any orbital phase, is found to be anticorrelated with the V light curve and is primarily ascribed to the chromospheric activity on the cool star. The primary total eclipse is clearly visible in the U band, but undetectable in the V band. From the U observations we determined a total duration of the primary eclipse (from 1^st^ to 4^rd^ contact) of 1.3883d, with the ingress lasting only 27 minutes. This new accurate monitoring and timing of the eclipse allowed us to improve the system solution which leads to R_C_=8.8R_{sun}_, T_C_=4800K, R_H_=0.11R_{sun}_, T_H_=30000K for the cool and hot star respectively. The evolution of HD 185510B is discussed also in relation to the evolutionary status of HD 185510A and the synchronization time scale. HD 185510B is probably a sdB near the zero age extended horizontal branch, resulting from an enhanced mass loss in late case B or case A mass exchange with a possible common envelope phase. A small amount (15-20%) of mass loss from the system which can account for the strong IR excess is suggested.
- ID:
- ivo://CDS.VizieR/J/A+A/426/247
- Title:
- HD 173977 uby photometry and HRV
- Short Name:
- J/A+A/426/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic and photometric observations of the star HD 173977. It appears that the star is part of a double line binary system, with a period of 1.801d, corresponding to twice the period of the photometric variations. Hence the star is an ellipsoidal variable. The system is probably synchronized. The physical parameters of both components were derived through two independent methods, one based on evolutionary tracks, the other being the result of the behaviour of light curves in a close binary system. After removing the ellipsoidal variations, 3 frequencies are detected in the photometric data: 8.56, 14.51 and 16.42d^-1^, while 2 additional frequencies are also possible: 10.96 and 12.11d^-1^. In accordance with its position in the HR diagram, the primary component of HD 173977 should be considered as a delta Scuti star and no longer as a gamma Doradus star. In addition, HD 173844, used as a check star, is discovered variable with a 15.79d^-1^ frequency and is classified as a delta Scuti star.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A85
- Title:
- HD 18078 uvby light curves
- Short Name:
- J/A+A/586/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The existence of a significant population of Ap stars with very long rotation periods (up to several hundred years) has progressively emerged over the past two decades. However, only lower limits of the periods are known for most of them because their variations have not yet been observed over a sufficient timebase. We determine the rotation period of the slowly rotating Ap star HD 18078 and we derive constraints on the geometrical structure of its magnetic field. We combine measurements of the mean magnetic field modulus obtained from 1990 to 1997 with determinations of the mean longitudinal magnetic field spanning the 1999-2007 time interval to derive an unambiguous value of the rotation period. We show that this value is consistent with photometric variations recorded in the Stromgren uvby photometric system between 1995 and 2004. We fit the variations of the two above-mentioned field moments with a simple model to constrain the magnetic structure.