HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope

Raskin, Gert; Winckel, H. Van; Hensberge, H.; Jorissen, A.; Lehmann, H.; Waelkens, Christoffel; Ávila, G.; Cuyper, J. P. de; Degroote, P.; Dubosson, Rene; Dumortier, L.; Frémat, Y.; Laux, U.; Michaud, Bernard; Morren, Johan; Padilla, Jesús Pérez; Pessemier, Wim; Prins, S.; Smolders, K.; Eck, S. Van; Winkler, Johannes

doi:10.1051/0004-6361/201015435

Cited by 460 publications

(442 citation statements)

References 13 publications

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“…The binary motion and a first estimate of the orbital period were based on data with a poor radial velocity accuracy and a poor sampling (Kodaira et al 1970). We therefore included this object in our longterm radial velocity monitoring programme (Van Winckel et al 2010) using our HERMES spectrograph (Raskin et al 2011). The orbital motion is clearly detected and in Fig.…”

Section: Discussionmentioning

confidence: 99%

TheWISEview of RV Tauri stars

Gezer

Winckel

Bozkurt

et al. 2015

Mon. Not. R. Astron. Soc.

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128

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We present a detailed study based on infrared photometry of all Galactic RV Tauri stars from the General Catalogue of Variable Stars (GCVS). RV Tauri stars are the brightest among the population II Cepheids. They are thought to evolve away from the asymptotic giant branch (AGB) towards the white dwarf domain. IRAS detected several RV Tauri stars because of their large IR excesses and it was found that they occupy a specific region in theWe used the all sky survey of WISE to extend these studies and compare the infrared properties of all RV Tauri stars in the GCVS with a selected sample of post-AGB objects with the goal to place the RV Tauri pulsators in the context of post-AGB evolution. Moreover, we correlated the IR properties of both the RV Tauri stars and the comparison sample with other observables like binarity and the presence of a photospheric chemical anomaly called depletion. We find that Galactic RV Tauri stars display a range of infrared properties and we differentiate between disc sources, objects with no IR excess and objects for which the spectral energy distribution (SED) is uncertain. We obtain a clear correlation between disc sources and binarity. RV Tauri stars with a variable mean magnitude are exclusively found among the disc sources. We also find evidence for disc evolution among the binaries. Furthermore our studies show that the presence of a disc seems to be a necessary but not sufficient condition for the depletion process to become efficient.

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Section: Discussionmentioning

confidence: 99%

TheWISEview of RV Tauri stars

Gezer

Winckel

Bozkurt

et al. 2015

Mon. Not. R. Astron. Soc.

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128

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“…In the spring of 2009, we started a high-resolution spectroscopic monitoring programme of 34 Galactic post-AGB candidates with disks and a few objects without an IR excess, that are observable from the northern hemisphere, using a newly built optical echelle spectrograph HERMES (Raskin et al 2011). These objects were required to satisfy at least two of the following criteria: an IR excess characteristic of a disk, an RV Tau-like variability, a variability indicative of a possible obscuration by a disk, a low surface gravity combined with a location away from the Galactic plane, and a deficiency in the refractory elements.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved spectroscopy of BD+46°442: Gas streams and jet creation in a newly discovered evolved binary with a disk

Gorlova

Winckel

Gielen

et al. 2012

A&A

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Context. Previous studies have shown that many post-asymptotic giant branch (AGB) stars with dusty disks are associated with single-lined binary stars. The inferred orbital separations are too small to accommodate a fully grown AGB star, hence these systems represent a new evolutionary channel that bypasses a full AGB evolution. Aims. We wish to verify the binarity hypothesis for a larger sample establish the nature of the companions, and probe the disk structure and eventually the disk formation mechanisms in binary stars. To achieve these aims, we started a high-resolution spectral monitoring of ∼40 field giants whose binarity had been suspected based on either a light curve, an infrared excess, or a peculiar chemical composition. Methods. Starting from the spring of 2009, we monitored the programme stars with the fibre echelle spectrometer HERMES. We measure their radial velocities (RVs) with a precision of ∼0.2 km s −1 , perform detailed photospheric abundance analyses, and analyse the time-resolved high-resolution spectra to search for line-profile variability.Results. Here we report on the discovery of periodic RV variations in BD+46 • 442, a high Galactic latitude F giant with a disk. We infer that the variations are caused by the motion around a faint companion, and deduce the orbital parameters P orb = 140.77 ± 0.02 d , e = 0.083± 0.002, and a sin i = 0.31 AU. We find that it is a moderately metal-poor star ([M/H] = −0.7) without a strong depletion pattern in its photospheric abundances. Interestingly, many lines indeed show periodic changes with the orbital phase: Hα switches between a double-peak emission line and a P Cyg-like profile, while strong metal lines appear to be split at the maximum redshift. Similar effects are likely visible in the spectra of other post-AGB binaries, but their regularity is not always apparent owing to sporadic observations. We propose that these features result from an ongoing mass transfer from the evolved giant to the companion. In particular, the blueshifted absorption in Hα, which occurs only at superior conjunction, may result from a jet originating in the accretion disk around the companion and that is seen in absorption towards the luminous primary.

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“…We obtained ten high-resolution, high signal-to-noise ratio (S/N) spectra for 43 Cygni using the HERMES spectrograph (R = 85, 000, λ = 377 − 900 nm, Raskin et al 2011) at the 1.2m Mercator telescope (Observatorio del Roque de los Muchachos, La Palma, Canary Islands, Spain). The observations were taken during 7 individual nights between August 4th and 15th, 2016, with typical exposure time of 600 s and S/N higher than 150 per pixel.…”

Section: Hermes Spectramentioning

confidence: 99%

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

Zwintz

Reeth

Tkachenko

et al. 2017

A&A

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Context. Photometric time series of the γ Doradus star 43 Cyg obtained with the BRITE-Constellation nano-satellites allow us to study its pulsational properties in detail and to constrain its interior structure. Aims. We aim to find a g-mode period spacing pattern that allows us to determine the near-core rotation rate of 43 Cyg and redetermine the star's fundamental atmospheric parameters and chemical composition.Methods. We conducted a frequency analysis using the 156-days long data set obtained with the BRITE-Toronto satellite and employed a suite of MESA/GYRE models to derive the mode identification, asymptotic period spacing and near-core rotation rate. We also used high-resolution, high signal-to-noise ratio spectroscopic data obtained at the 1.2m Mercator telescope with the HER-MES spectrograph to redetermine the fundamental atmospheric parameters and chemical composition of 43 Cyg using the software Spectroscopy Made Easy (SME). Results. We detected 43 intrinsic pulsation frequencies and identified 18 of them to be part of a period spacing pattern consisting of prograde dipole modes with an asymptotic period spacing ∆Π l=1 of 2970 +700 −570 s. The near-core rotation rate was determined to be f rot = 0.56 +0.12 −0.14 d −1 . The atmosphere of 43 Cyg shows solar chemical composition at an effective temperature, T eff , of 7150 ± 150 K, a log g of 4.2 ± 0.6 dex and a projected rotational velocity, υ sin i, of 44 ± 4 km s −1 . Conclusions. The morphology of the observed period spacing patterns shows indications of the presence of a significant chemical gradient in the stellar interior.

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HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope

Cited by 460 publications

References 13 publications

TheWISEview of RV Tauri stars

TheWISEview of RV Tauri stars

Time-resolved spectroscopy of BD+46°442: Gas streams and jet creation in a newly discovered evolved binary with a disk

Constraining the near-core rotation of theγDoradus star 43 Cygni using BRITE-Constellation data

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