Erratum: “First Results from the CHARA Array. VII. Long‐Baseline Interferometric Measurements of Vega Consistent with a Pole‐On, Rapidly Rotating Star” (ApJ, 645, 664 [2006])

Aufdenberg, J. P.; Mérand, A.; Foresto, V. Coudé du; Absil, Olivier; Folco, E. Di; Kervella, P.; Ridgway, Stephen T.; Berger, David H.; Brummelaar, Theo A. ten; McAlister, Harold A.; Sturmann, J.; Sturmann, L.; Turner, N.

doi:10.1086/507484

Cited by 79 publications

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“…Although stellar structure and evolution models are now quite successful in reproducing the observed physical properties of most A-type stars, the observational constraints on these models remain relatively weak, occasionally leading to surprising discoveries. An example is provided by the recent interferometric observations of the A0V benchmark star Vega, which confirmed that Vega, as previously shown by Gulliver et al (1994), is a pole-on fast rotator near its critical velocity (Aufdenberg et al 2006). The same interferometric observations showed that Vega harbors a hot debris disk within 8 AU from the star (Absil et al 2006).…”

Section: Introductionsupporting

confidence: 74%

The nearby eclipsing stellar systemδVelorum

Pribulla¹,

Mérand²,

Kervella

et al. 2011

A&A

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Context. The triple stellar system δ Vel (composed of two A-type and one F-type main-sequence stars) is particularly interesting because it contains one of the nearest and brightest eclipsing binaries. It therefore presents a unique opportunity to determine independently the physical properties of the three components of the system, as well as its distance. Aims. We aim at determining the fundamental parameters (masses, radii, luminosities, rotational velocities) of the three components of δ Vel, as well as the parallax of the system, independently from the existing Hipparcos measurement. Methods. We determined dynamical masses from high-precision astrometry of the orbits of Aab-B and Aa-Ab using adaptive optics (VLT/NACO) and optical interferometry (VLTI/AMBER). The main component is an eclipsing binary composed of two early A-type stars in rapid rotation. We modeled the photometric and radial velocity measurements of the eclipsing pair Aa-Ab using a self-consistent method based on physical parameters (mass, radius, luminosity, rotational velocity). Results. From our self-consistent modeling of the primary and secondary components of the δ Vel A eclipsing pair, we derive their fundamental parameters with a typical accuracy of 1%. We find that they have similar masses, 2.43 ± 0.02 M and 2.27 ± 0.02 M . The physical parameters of the tertiary component (δ Vel B) are also estimated, although to a lower accuracy. We obtain a parallax π = 39.8 ± 0.4 mas for the system, in satisfactory agreement (−1.2 σ) with the Hipparcos value (π Hip = 40.5 ± 0.4 mas). Conclusions. The physical parameters we derive represent a consistent set of constraints for the evolutionary modeling of this system. The agreement of the parallax we measure with the Hipparcos value to a 1% accuracy is also an interesting confirmation of the true accuracy of these two independent measurements.

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Section: Introductionsupporting

confidence: 74%

The nearby eclipsing stellar systemδVelorum

Pribulla¹,

Mérand²,

Kervella

et al. 2011

A&A

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“…A fast rotating star usually presents a UV excess due to its overheated polar caps (von Zeipel effect, see e.g. Aufdenberg et al 2006). A discussion on the rotational velocity of the components of δ Vel A can be found in Argyle et al (2002).…”

Section: Discussionmentioning

confidence: 99%

The nearby eclipsing stellar systemδVelorum

Kervella¹,

Thévenin

Petr-Gotzens

2008

A&A

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Context. The triple stellar system δ Vel system presents a significant infrared excess, whose origin is still being debated. A large infrared bow shock has been discovered using Spitzer/MIPS observations. Although it appears as a significant contributor to the measured IR excess, the possibility exists that a circumstellar IR excess is present around the stars of the system. Aims. The objective of the present VISIR and NACO observations is to identify whether one of the stars of the δ Vel system presents a circumstellar photometric excess in the thermal IR domain and to quantify it. Methods. We observed δ Vel using the imaging modes of the ESO/VLT instruments VISIR (in BURST mode) and NACO to resolve the A-B system (0.6 separation) and obtain the photometry of each star. We also obtained one NACO photometry epoch precisely at the primary (annular) eclipse of δ Vel Aa by Ab. Results. Our photometric measurements with NACO (2.17 μm), complemented by the existing visible photometry allowed us to reconstruct the spectral energy distribution of the three stars. We then compared the VISIR photometry (8.6-12.8 μm) to the expected photospheric emission from the three stars at the corresponding wavelengths. Conclusions. We can exclude the presence of a circumstellar thermal infrared excess around δ Vel A or B down to a few percent level. This supports the conclusions of Gáspár et al. (2008, ApJ, 672, 974) that the IR excess of δ Vel has an interstellar origin, although a cold circumstellar disk could still be present. In addition, we derive the spectral types of the three stars Aa, Ab, and B (respectively A2IV, A4V and F8V), and we estimate the age of the system around 400-500 Myr.

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“…The interstellar medium (ISM) would be more efficiently compressed along the polar axis, thus elongating the cavity carved by the star in the dusty ISM. Another additional pressure would come from the enhanced ultraviolet flux as seen from above the stellar poles, compared to the darkened equatorial belt (due to the Von Zeipel effect: see Aufdenberg et al 2006 for an application to Vega).…”

Section: Origins and Evolution Of The Csesmentioning

confidence: 99%

The circumstellar envelopes of the Cepheids $\mathsf{\ell}$ Carinae and RS Puppis

Kervella¹,

Mérand

Gallenne

2009

A&A

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Context. Compact circumstellar envelopes (CSEs) have been detected around several Cepheids by interferometry. In particular, observations with the VINCI instrument revealed in 2006 a compact envelope around the long period Cepheid Car (P = 35.5 days). Another Cepheid, RS Pup (P = 41.4 days), presents a large (≈2 ) circumstellar nebula scattering the Cepheid light in the visible. These envelopes are particularly interesting for two reasons: their presence could impact the Cepheid distance scale, and they could imply stellar mass loss. Aims. Our goal is to establish the spatial and spectral properties of the CSEs of Car and RS Pup. This is done through a parametrization of the envelopes in terms of fractional flux (with respect to the star) and angular size. Methods. We retrieved archival Spitzer images of the two stars (λ = 3.5−70 μm), and obtained new diffraction-limited imaging with the VLT/VISIR camera in BURST mode (λ = 8.6−11.9 μm), as well as interferometric observations with the VLTI/MIDI beam combiner (λ = 8−13 μm). This combination of single-telescope and interferometric techniques allows us to probe the envelopes of the two Cepheids over a broad range of angular scales, from arcminutes to milliarcseconds. Results. The circumstellar envelope of RS Pup is resolved spatially at 24 and 70 μm by Spitzer, and around 10 μm by MIDI and VISIR. The envelope of Car appears much more compact, and is resolved only in the VISIR and MIDI observations. The infrared excesses we detect around RS Pup and Car are both very significant, but differ considerably in spectral and spatial properties. We detect a warm component in the CSE of both stars at a spatial scale of a few 100 to a few 1000 AU. In addition, RS Pup presents a very large (several 100 000 AU) and cold (≈40 K) dusty envelope. Conclusions. The observed properties of the CSEs lead us to propose that the cold dust content of the large reflection nebula surrounding RS Pup has an interstellar origin, while the warm CSEs of the two stars were created by ongoing stellar mass loss. We also speculate that the NGC 7023 reflection nebula surrounding the Herbig Be star HD 200775 is an analogue of RS Pup at an age of 100 000 years. The presence of CSEs around the two brightest long-period Cepheids is an indication that many long-period members of this class, if not all, could be surrounded by warm circumstellar envelopes created by mass loss. However, very large dusty envelopes such as that of RS Pup are probably less common, as according to our scenario, they require the presence of a high dust density in the interstellar medium (ISM) at the time of the formation of the Cepheid progenitor.

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Erratum: “First Results from the CHARA Array. VII. Long‐Baseline Interferometric Measurements of Vega Consistent with a Pole‐On, Rapidly Rotating Star” (ApJ, 645, 664 [2006])

Cited by 79 publications

References 0 publications

The nearby eclipsing stellar systemδVelorum

The nearby eclipsing stellar systemδVelorum

The nearby eclipsing stellar systemδVelorum

The circumstellar envelopes of the Cepheids $\mathsf{\ell}$ Carinae and RS Puppis

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