A5093734346- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Optical Polarization and Ellipsometry
- Plant Toxicity and Pharmacological Properties
- Agricultural safety and regulations
- Geophysics and Gravity Measurements
- Remote Sensing in Agriculture
- Plant Reproductive Biology
- Time Series Analysis and Forecasting
- Botanical Research and Chemistry
- Pharmacological Effects of Medicinal Plants
- Astronomical Observations and Instrumentation
- Neurobiology and Insect Physiology Research
- Radio Astronomy Observations and Technology
- Bee Products Chemical Analysis
Université Paris Cité
2024
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2024
Observatoire de Paris
2024
Centre National de la Recherche Scientifique
2024
Sorbonne Université
2024
Université de Versailles Saint-Quentin-en-Yvelines
2024
Université Paris Sciences et Lettres
2024
Délégation Paris 7
2024
Surface brightness--colour relations (SBCRs) are widely used to determine the angular diameters of stars. They in particular Baade-Wesselink (BW) method distance determination Cepheids. However, impact SBCR on BW Cepheids is about 8%, depending choice considered literature. We aim calibrate a precise dedicated using best quality interferometric measurements available as well different photometric bands, including Gaia bands. selected and data literature for seven covering pulsation periods....
To use the period-luminosity relations of Cepheids to derive distances extragalactic Cepheids, it is crucial have reliable estimations luminosity such stars. However, light curves (LCs) are sparsely sampled, which makes interpolation difficult. Our purpose create general templates Cepheid LCs that can be efficiently applied with only a few parameters, while ensuring they in terms resulting mean magnitudes. We also aimed provide adaptable for large variety photometric bands enlarge their...
Abstract The 30 yr orbit of the Cepheid Polaris has been followed with observations by Center for High Angular Resolution Astronomy (CHARA) Array from 2016 through 2021. An additional measurement made speckle interferometry at Apache Point Observatory. Detection companion is complicated its comparative faintness—an extreme flux ratio. diameter measurements appear to show some variation pulsation phase. Astrometric positions were measured a custom grid-based model-fitting procedure and...
The circumstellar envelopes (CSE) of Cepheids are still only poorly characterized despite their potential impact on the distance determination via both period-luminosity relation and parallax-of-pulsation method. This paper aims to investigate Galactic across instability strip in mid-infrared with MATISSE/VLTI order constrain geometry physical nature (gas and/or dust) CSEs. We secured observations eight short- up long-period pulsations L, M, N bands. For each star, we calibrated flux...
Context . The application of the parallax-of-pulsation (PoP) technique to determine distances pulsating stars implies use a scaling parameter, namely projection factor ( p -factor), which is required transform disc-integrated radial velocities (RVs) into photospheric expansion velocities. value this parameter poorly known and still debated. Most present applications PoP assume constant -factor. However, it may actually depend on physical parameters each star, as past studies designed...
Context. An inner companion has recently been discovered orbiting the prototype of classical Cepheids, δ Cep, whose orbital parameters are still not fully constrained. Aims. We collected new precise radial velocity measurements Cep in 2019 using HARPS-N spectrograph mounted at Telescopio Nazionale Galileo . Using these measurements, we aimed to improve system. Methods. considered a template available literature as reference for curve pulsation star. then calculated residuals between our...
The application of the parallax pulsation (PoP) technique to determine distances pulsating stars implies use a scaling parameter, projection factor (p-factor), required transform disc-integrated radial velocities (RVs) into photospheric expansion velocities. value p-factor is poorly known and debated. Most PoP applications assume constant p-factor. However, it may actually depend on physical parameters each star. We aim calibrate p-factors for RR Lyrae (RRLs) compare them with classical...
Type II Cepheids are old pulsating stars that can be used to trace the distribution of an stellar population and measure distances globular clusters galaxies within several megaparsecs. One method relies on period-luminosity relations, which quite widely explored in literature. The semi-geometrical Baade-Wesselink technique is another allows radially stars, such as Cepheids, measured if so-called projection factor known. Using surface brightness-colour relation version technique, we...
Context. Type II Cepheids are old pulsating stars that can be used to trace the distribution of an stellar population and measure distances globular clusters galaxies within several megaparsecs, by extension, they improve our understanding cosmic distance scale. One method relies on period-luminosity relations, which quite widely explored in literature. The semi-geometrical Baade-Wesselink technique is another allows radially stars, such as Cepheids, measured if so-called projection factor...
The 30 year orbit of the Cepheid Polaris has been followed with observations by CHARA Array (Center for High Angular Resolution Astronomy) from 2016 through 2021. An additional measurement made speckle interferometry at Apache Point Observatory. Detection companion is complicated its comparative faintness--an extreme flux ratio. diameter measurements appear to show some variation pulsation phase. Astrometric positions were measured a custom grid-based model-fitting procedure and confirmed...
Context. The Baade-Wesselink (BW) method, also known as the pulsation parallax allows us to estimate distances individual pulsating stars. Accurate geometric parallaxes obtained by Gaia mission serve in calibration of method and determination its precision. This provides a way determining mean radii Aims. main aim this work is determine scatter possible dependence p -factors RR Lyrae stars on their periods. secondary objective radius-period relations for these Methods. Our calibrations are...
The Baade-Wesselink method allows us to estimate distances individual pulsating stars. Accurate geometric parallaxes obtained by the Gaia mission serve in calibration of and determination its precision. also provides a way determining mean radii main aim this work is determine scatter possible dependence p- factors RR Lyrae stars on their pulsation periods. secondary objective radius - period relations for these Our calibrations are based photometric data gathered at Cerro Murphy...
The circumstellar envelopes (CSE) of Cepheids are still not well characterized despite their potential impact on distance determination via both the period-luminosity relation and parallax-of-pulsation method. This paper aims to investigate Galactic across instability strip in mid-infrared with MATISSE/VLTI order constrain geometry physical nature (gas and/or dust) CSEs. We secured observations eight from short up long period pulsation, $L$, $M$ $N$-bands. SED analysis mid-IR confirms...