- ID:
- ivo://CDS.VizieR/J/A+A/493/1043
- Title:
- High spatial resolution observations of HM Sge
- Short Name:
- J/A+A/493/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high spatial resolution observations of the close circumstellar environment of the symbiotic system HM Sagittae obtained with the Very Large Telescope Interferometer (VLTI) of ESO's Paranal Observatory and MIDI, the MID-infrared Interferometric recombiner. MIDI combines the light of two telescopes and provides spectrally resolved visibilities in the N band atmospheric window. The observations of HM Sge were conducted with the VLT Auxiliary Telescopes (ATs) A0, D0, G1 and H0, providing projected baselines in the range of 64 to 89 meters oriented from PA=72 to 127{deg}. The ATs observations were made during the nights of April 04, May 08/10/16, and July 30. All the observations were made under good atmospheric conditions (average seeing ~0.62") with the worst seeing (~1.05") during the night of July 30 2007. The files includes all visibility and differential phase data recorded from these observations as well as all the characteristics concerning the observations. The log of the observations is shown in the third part of table1. The set of data are complementary to the ones corresponding to the first two parts of Table 1 of the paper previously published in Sacuto et al. (2007, Cat. <J/A+A/465/469>)
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/465/469
- Title:
- High spatial resolution observations of HM Sge
- Short Name:
- J/A+A/465/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high spatial resolution observations of the mid-infrared core of the dusty symbiotic system HM Sge obtained with the Very Large Telescope Interferometer (VLTI) of ESO's Paranal Observatory and MIDI, the MID-infrared Interferometric recombiner. MIDI combines the light of two telescopes and provides spectrally resolved visibilities in the N band atmospheric window. The observations of HM Sge were conducted with the VLT Unit Telescopes (UTs) UT2, UT3 and UT4, providing projected baselines in the range of 32-59 meters oriented from PA=42deg to 105deg and the Auxiliary Telescopes (ATs) E0 and G0, providing projected baselines in the range of 13.5-16 meters oriented around PA=75deg. The UTs observations were made during the nights of July 23-24th 2005, May 17th 2006 and June 11th 2006. The ATs observations were made during the nights of May 27th 2006 and June 16th 2006. All the observations were made under good atmospheric conditions (Mean[seeing]~1.01") with the worst seeing (~1.75") during the night of July 23th 2005. The files includes all visibility and differential phase data recorded from these observations as well as all the characteristics concerning the observations. The log of the observations is shown in Table 1 of the paper (table1.dat).
- ID:
- ivo://CDS.VizieR/J/A+A/482/561
- Title:
- High spatial resolution observations of pi^1^ Gru
- Short Name:
- J/A+A/482/561
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high spatial resolution observations of the close circumstellar environment of the semi-regular S-type star pi^1^ Gruis obtained with the Very Large Telescope Interferometer (VLTI) of ESO's Paranal Observatory and MIDI, the MID-infrared Interferometric recombiner. MIDI combines the light of two telescopes and provides spectrally resolved visibilities in the N band atmospheric window. The observations of pi^1^ Gruis were conducted with the VLT Auxiliary Telescopes (ATs) A0, E0, D0 and G0, providing projected baselines in the range of 15 to 64 meters oriented from PA=41 to 102{deg}. The ATs observations were made during the nights of May 21-23-24-25-27 2006, June 19 2006, and August 08 2006. All the observations were made under good atmospheric conditions (average seeing ~0.94") with the worst seeing (~1.51") during the night of May 27 2006. The files includes all visibility and differential phase data recorded from these observations as well as all the characteristics concerning the observations. The log of the observations is shown in Table 1.
- ID:
- ivo://CDS.VizieR/J/AJ/156/150
- Title:
- High-time-resolution photometry of AR Scorpii
- Short Name:
- J/AJ/156/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The unique binary AR Scorpii consists of an asynchronously rotating, magnetized white dwarf (WD) that interacts with its red-dwarf companion to produce a large-amplitude, highly coherent pulsation every 1.97 minutes. Over the course of two years, we obtained 39 hours of time-resolved, optical photometry of AR Sco at a typical cadence of 5 s to study this pulsation. We find that it undergoes significant changes across the binary orbital period and that its amplitude, phase, and waveform all vary as a function of orbital phase. We show that these variations can be explained by constructive and destructive interference between two periodic, double-peaked signals: the spin-orbit beat pulse, and a weaker WD spin pulse. Modeling of the light curve indicates that in the optical, the amplitude of the primary spin pulse is 50% of the primary beat amplitude, while the secondary maxima of the beat and spin pulses have similar amplitudes. Finally, we use our timings of the beat pulses to confirm the presence of the disputed spin-down of the WD. We measure a beat-frequency derivative of {nu}=(-5.14+/-0.32)x10^-17^ Hz/s and show that this is attributable to the spin-down of the WD. This value is approximately twice as large as the estimate from Marsh et al. but is nevertheless consistent with the constraints established in Potter & Buckley (2018MNRAS.478L..78P). Our precise measurement of the spin-down rate confirms that the decaying rotational energy of the magnetized WD is sufficient to power the excess electromagnetic radiation emitted by the binary.
515. H235 in NGC 752
- ID:
- ivo://CDS.VizieR/J/AJ/109/359
- Title:
- H235 in NGC 752
- Short Name:
- J/AJ/109/359
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The short-period variable star Heinemann 235 in the open cluster NGC 752 has been identified as a contact binary with a variable period of about 0.4118 d. BVRI light curves and radial velocity curves have been obtained and analyzed with enhanced versions of the Wilson-Devinney light curve program. We find that the system is best modeled as an A-type W UMa system, with a contact parameter of 0.21 +/- 0.11. The masses of the components are found to be 1.18 +/- 0.17 and 0.24 +/- 0.04 Msun, with bolometric magnitudes of 3.60 +/- 0.10 and 5.21 +/- 0.13, for the hotter (6500 K, assumed) and cooler (6421 K) components, respectively, with Delta T = 79 +/- 25 K. The distance to the binary is established at 381 +/- 17 pc. H235 becomes one of a relatively small number of open-cluster contact systems with detailed light curve analysis for which an age may be estimated. If it is coeval with the cluster, and with the detached eclipsing and double-lined spectroscopic binary H219 (DS And), H235 is ~1.8 Gyr old, and may provide a fiducial point for the evolution of contact systems. There is, however, evidence for dynamical evolution of the cluster and the likelihood of weak interactions over the age of the binary precludes the determination of its initial state with certainty.
- ID:
- ivo://CDS.VizieR/J/A+A/399/1167
- Title:
- Hipparcos Variability-Induced Movers
- Short Name:
- J/A+A/399/1167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hipparcos observations of some variable stars, and especially of long-period (e.g. Mira) variables, reveal a motion of the photocenter correlated with the brightness variation (variability-induced mover, VIM), suggesting the presence of a binary companion. A re-analysis of the Hipparcos photometric and astrometric data (Cat. <I/239>) does not confirm the VIM solution for 62 among the 288 VIM objects (21%) in the Hipparcos catalogue. Most of these 288 VIMs are long-period (e.g. Mira) variables (LPV). The effect of a revised chromaticity correction, which accounts for the color variations along the light cycle, was then investigated. It is based on "instantaneous" V-I color indices derived from Hipparcos and Tycho-2 (Cat. <I/259>) epoch photometry. Among the 188 LPVs flagged as VIM in the Hipparcos catalogue, 89 (47%) are not confirmed as VIM after this improved chromaticity correction is applied. This dramatic decrease in the number of VIM solutions is not surprising, since the chromaticity correction applied by the Hipparcos reduction consortia was based on a fixed V-I color. Astrophysical considerations lead us to adopt a more stringent criterion for accepting a VIM solution (first-kind risk of 0.27% instead of 10% as in the Hipparcos catalogue). With this more severe criterion, only 27 LPV stars remain VIM, thus rejecting 161 of the 188 (86%) of the LPVs defined as VIMs in the Hipparcos catalogue.
- ID:
- ivo://CDS.VizieR/J/A+A/367/297
- Title:
- Hipparcos variable stars
- Short Name:
- J/A+A/367/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The data known as the Hipparcos Photometry obtained with the Hipparcos satellite have been investigated to find those stars which are least variable. Such stars are excellent candidates to serve as standards for photometric systems. Their spectral types suggest in which parts of the HR diagrams stars are most constant. In some cases these values strongly indicate that previous ground based studies claiming photometric variability are incorrect or that the level of stellar activity has changed.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1350
- Title:
- Hot variable stars in NGC 330
- Short Name:
- J/AJ/135/1350
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a sample of 150 hot stars in NGC 330, a SMC cluster containing a high fraction of Be stars, we searched for photometric variables using OGLE II data. At least one third of all stars are variable, with 38 being periodic. We found 27 pulsators ({lambda} Eri variables), six eclipsing systems, two bursting sources, and several stars with unusual photometric behavior. Pulsations are present in ~30% of known Be stars, and they are long lived, lasting more than a decade. The strongest pulsators are associated with stars evolved from the main sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A54
- Title:
- HR4796A dust ring Stokes images
- Short Name:
- J/A+A/626/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The scattering properties of the dust originating from debris discs are still poorly known. The analysis of scattered light is however a powerful remote-sensing tool to understand the physical properties of dust particles orbiting other stars. Scattered light is indeed widely used to characterise the properties of cometary dust in the solar system. We aim to measure the morphology and scattering properties of the dust from the debris ring around HR4796A in polarised optical light. We obtained high-contrast polarimetric images of HR4796A in the wavelength range 600-900nm with the SPHERE/ZIMPOL instrument on the Very Large Telescope. We measured for the first time the polarised phase function of the dust in a debris system over a wide range of scattering angles in the optical. We confirm that it is incompatible with dust particles being compact spheres under the assumption of the Mie theory, and propose alternative scenarios compatible with the observations, such as particles with irregular surface roughness or aggregate particles.
- ID:
- ivo://CDS.VizieR/J/A+A/429/309
- Title:
- HR 1099 radial velocities
- Short Name:
- J/A+A/429/309
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied orbital period changes in the non-eclipsing close binary HR 1099, one of the most bright members of the RS CVn class of magnetically active binary systems. Intermediate-resolution optical spectroscopy and IUE archive spectra were used to build radial-velocity curves yielding epochs of superior conjunction with an accuracy of 0.01 days. The final database ranged from 1976 to 2002 and allowed us a better assessment of the amplitude of the orbital period variation and its timescale.
