Imaging the Surface of Altair

Monnier, John D.; Zhao, M.; Pedretti, E.; Thureau, N.; Ireland, Michael; Muirhead, Philip S.; Berger, J. P.; Millan-Gabet, R.; Belle, Gerald van; Brummelaar, T. ten; McAlister, Harold A.; Ridgway, Stephen T.; Turner, N.; Sturmann, L.; Sturmann, J.; Berger, David H.

doi:10.1126/science.1143205

Cited by 329 publications

(311 citation statements)

References 39 publications

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“…Fig. 3) as the solution parameters {ω, R pole , i, α, β} found in Monnier et al (2007) are given 1-σ excursions from their best-fit values. The practicalities of χ 2 minimization of interferometric data are highlighted in Sect.…”

Section: Observational Quantities Predictionsmentioning

confidence: 99%

“…Ultimately, these studies collectively set the stage for the ground-breaking study by Monnier et al (2007), which was the first to directly image a main sequence star. The data from the MIRC instrument on the CHARA Array directly confirmed the presence of gravity darkening using an image reconstruction independent of the previous parametric modeling approaches, while at the same time providing evidence that departures from the standard formulation of that effect were insufficient to explain the observations.…”

Section: Altairmentioning

confidence: 99%

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Interferometric observations of rapidly rotating stars

Belle

2012

Astron Astrophys Rev

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Optical interferometry provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Through direct observation of rotationally distorted photospheres at sub-milliarcsecond scales, we are now able to characterize latitude dependencies of stellar radius, temperature structure, and even energy transport. These detailed new views of stars are leading to revised thinking in a broad array of associated topics, such as spectroscopy, stellar evolution, and exoplanet detection. As newly advanced techniques and instrumentation mature, this topic in astronomy is poised to greatly expand in depth and influence.

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Section: Observational Quantities Predictionsmentioning

confidence: 99%

Section: Altairmentioning

confidence: 99%

Interferometric observations of rapidly rotating stars

Belle

2012

Astron Astrophys Rev

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“…Stellar surfaces of five intermediate-mass fast-rotators were imaged in the K band using the CHARA/MIRC instrument (Monnier et al 2007b, Zhao et al 2009, Che et al 2011. The reconstructed images, presented in Fig.…”

Section: From Diameters Measurements To Stellar Imagingmentioning

confidence: 99%

An interferometric journey around massive stars

Meilland¹,

Stee²

2014

Proc. IAU

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Abstract. Since the construction in the late nineties of modern facilities such as the VLTI or CHARA, interferometry became a key technique to probe massive stars and their oftencomplex circumstellar environments. Over the last decade, the development of a new generation of beam combiners for these facilities enabled major breakthroughs in the understanding of the formation and evolution of massive stars. In this short review, we will present few of these advances concerning young stellar objects, binarity, mass loss, and stellar surfaces.

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“…Several teams have observed the absolute spin axis orientation of a dozen early-type stars: Altair (Monnier et al 2007), Vega (Peterson et al 2006), and Achenar (Domiciano de Souza et al 2003). The spin axis orientation is actually a by-product of determining the gravitational limb darkening coefficient for these fast rotating stars.…”

Section: Introductionmentioning

confidence: 99%

Determination of the position angle of stellar spin axes

Lesage

Wiedemann

2014

A&A

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Context. Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. Aims. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis of high resolution long-slit spectra. The method has been designed in particular for slowly rotating stars. We investigate its applicability to existing dispersive long-slit spectrographs, identified here by their plate scale, and the size of the resulting stellar sample. Methods. The stellar rotation induces a tilt in the stellar lines whose angle depends on the stellar position angle and the orientation of the slit. We developed a rotation model to calculate and reproduce the effects of stellar rotation on unreduced high resolution stellar spectra. Then we retrieved the tilt amplitude using a spectro-astrometric extraction of the position of the photocentre of the spectrum. Finally we present two methods for analysing the position spectrum using either direct measurement of the tilt or a cross-correlation analysis.Results. For stars with large apparent diameter and using a spectrograph with a small plate scale, we show that it is possible to determine the stellar position angle directly within 10 • with a signal-to-noise ratio of the order of 6. Under less favourable conditions, i.e. larger plate scale or smaller stellar diameter, the cross-correlation method yields comparable results. Conclusions. We show that with the currently existing instruments, it is possible to determine the stellar position angle of at least 50 stars precisely, mostly K-type giants with apparent diameter down to 5 milliarcseconds. If we consider errors of around 10 • still acceptable, we may include stars with apparent diameter down to 2 mas in the sample that then comprises also some main sequence stars.

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Imaging the Surface of Altair

Cited by 329 publications

References 39 publications

Interferometric observations of rapidly rotating stars

Interferometric observations of rapidly rotating stars

An interferometric journey around massive stars

Determination of the position angle of stellar spin axes

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