The multiplicity of<i>φ</i>Phe revisited

Pourbaix, D.; Boffin, H. M. J.; Chini, R.; Dembsky, T.

doi:10.1051/0004-6361/201321699

Cited by 5 publications

(4 citation statements)

References 18 publications

(24 reference statements)

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“…Finally, the binarity of the star ϕ Phe may have affected the amplitude of both the observed and the modelled light variability. However, Pourbaix et al (2013) reports a magnitude difference of 5.7 in V and 3.9 in K. It is therefore unlikely that the secondary component could have affected the light variability significantly.…”

Section: Discussionmentioning

confidence: 94%

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The nature of the photometric variability of HgMn stars: A test of simulated light curves of ϕ Phe against the TESS data

Prvák,

Krtička,

Korhonen

2019

Preprint

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The inhomogeneous surface distribution of heavy elements is known to cause periodic light variability of magnetic chemically peculiar stars. It is unclear to what extent the same paradigm applies to mercury-manganese (HgMn) stars. We aim to model the photometric variability of the HgMn star ϕ Phe using abundance maps obtained from high-resolution spectroscopy and to study how this variability evolves with time. We compute a grid of atlas12 model atmospheres and the corresponding synspec synthetic spectra. Interpolating within this grid and integrating the specific intensity over the visible stellar surface at different rotational phases, we obtain theoretical light curves of the star. We predict the variability of ϕ Phe in the ultraviolet and in the visible spectral regions with amplitude of the order of millimagnitudes, mainly caused by absorption in lines of yttrium, chromium, and titanium. We also show how this variability is affected by changes of the distribution of the heavy elements over time. The main characteristics of the predicted light variability of ϕ Phe correspond roughly to the variability of the star observed with the TESS satellite.

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Section: Discussionmentioning

confidence: 94%

“…The star ϕ Phe is a spectroscopic binary (Pourbaix et al 2013). The inhomogeneous distribution of heavy elements was investigated by Briquet et al (2010) and later revisited in Korhonen et al (2013).…”

Section: Crmentioning

confidence: 99%

The nature of the photometric variability of HgMn stars: A test of simulated light curves of ϕ Phe against the TESS data

Prvák,

Krtička,

Korhonen

2019

Preprint

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“…TIC 229099027 (HD 11753, 𝜑 Phe) is a well-known spectroscopically variable HgMn star with evolving surface distributions of chemical elements (Briquet et al 2010;Makaganiuk et al 2012;Korhonen et al 2013). It is a member of a long-period, potentially eclipsing, SB1 system with 𝑃 orb = 1126 d (Pourbaix et al 2013). The rotational period found in spectroscopy, 𝑃 rot = 9.531 d, is longer than the 9.324(1) d period that provides the best description of the TESS light curve of this star.…”

Section: Rotational Variabilitymentioning

confidence: 99%

TESS survey of rotational and pulsational variability of mercury-manganese stars

Kochukhov,

Khalack,

Kobzar

et al. 2021

Preprint

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Mercury-manganese (HgMn) stars are late-B upper main sequence chemically peculiar stars distinguished by large overabundances of heavy elements, slow rotation, and frequent membership in close binary systems. These stars lack strong magnetic fields typical of magnetic Bp stars but occasionally exhibit non-uniform surface distributions of chemical elements. The physical origin and the extent of this spot formation phenomenon remains unknown. Here we use 2-min cadence light curves of 64 HgMn stars observed by the TESS satellite during the first two years of its operation to investigate the incidence of rotational modulation and pulsations among HgMn stars. We found rotational variability with amplitudes of 0.1-3 mmag in 84 per cent of the targets, indicating ubiquitous presence of starspots on HgMn-star surfaces. Rotational period measurements reveal six fast-rotating stars with periods below 1.2 d, including one ultra-fast rotator (HD 14228) with a 0.34 d period. We also identify several HgMn stars showing multi-periodic g-mode pulsations, tidally induced variation and eclipses in binary systems.

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“…The approach described here is well-known within the astronomical literature, being Hartkopf et al (1989); Pourbaix (1994); Lucy (2014), and Mendez et al (2017) some examples of its use.…”

Section: Dynamics Of a Binary Starmentioning

confidence: 99%

Visual Binary Stars with Partially Missing Data: Introducing Multiple Imputation in Astrometric Analysis

Clavería

Mendez

Silva

et al. 2019

PASP

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Partial measurements of relative position are a relatively common event during the observation of visual binary stars. However, these observations are typically discarded when estimating the orbit of a visual pair. In this article we present a novel framework to characterize the orbits from a Bayesian standpoint, including partial observations of relative position as an input for the estimation of orbital parameters. Our aim is to formally incorporate the information contained in those partial measurements in a systematic way into the final inference. In the statistical literature, an imputation is defined as the replacement of a missing quantity with a plausible value. To compute posterior distributions of orbital parameters with partial observations, we propose a technique based on Markov chain Monte Carlo with multiple imputation. We present the methodology and test the algorithm with both synthetic and real observations, studying the effect of incorporating partial measurements in the parameter estimation. Our results suggest that the inclusion of partial measurements into the characterization of visual binaries may lead to a reduction in the uncertainty associated to each orbital element, in terms of a decrease in dispersion measures (such as the interquartile range) of the posterior distribution of relevant orbital parameters. The extent to which the uncertainty decreases after the incorporation of new data (either complete or partial) depends on how informative those newly-incorporated measurements are. Quantifying the information contained in each measurement remains an open issue. 2 R. Claveria et al.observed, angular separations beyond the angular resolution of the telescope, etc. The latter case is arguably the most common source of partial information: in the vicinity of the periastron, the angular separation between the primary and secondary star (denoted by ρ hereafter) reaches its minimum values; if those values fall below the resolution threshold of the imaging device, then the angular separation is confined to a range (i.e., ρ ∈ (0, ρ max )) instead of being reduced to a single value (as occurs with regular, successfully resolved measurements), and usually no information about the position angle of the secondary with respect to the primary (denoted by ϑ hereafter) can be inferred either. In certain cases, databases of visual binary observations also report partial data of the form ρ = (0, ∞), ϑ = ϑ * , that is, the angular separation is missing but the position angle is well-defined. Many example of partially missing data (in ρ or ϑ) can be found by browsing either through the historical measurements database of the Washington Double Star Catalogue (WDS hereafter, Mason et al. (2001)) or the Catalog of Interferometric Measurements of Binary Stars (INT hereafter, Hartkopf et al. (2001)), both diligently curated by the Naval Observatory of the United States 1 .In a broader context, from population censuses to clinical research surveys, the presence of incomplete or missing data may occur in a wide ...

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The multiplicity ofφPhe revisited

Cited by 5 publications

References 18 publications

The nature of the photometric variability of HgMn stars: A test of simulated light curves of ϕ Phe against the TESS data

The nature of the photometric variability of HgMn stars: A test of simulated light curves of ϕ Phe against the TESS data

TESS survey of rotational and pulsational variability of mercury-manganese stars

Visual Binary Stars with Partially Missing Data: Introducing Multiple Imputation in Astrometric Analysis

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