Spectroscopic survey of Kepler stars.★ I. HERMES/Mercator observations of A- and F-type stars

Niemczura, E.; Murphy, Simon J.; Smalley, B.; Uytterhoeven, K.; Pigulski, A.; Lehmann, H.; Bowman, D. M.; Catanzaro, G.; Aarle, E. van; Bloemen, S.; Briquet, Maryline; Cat, P. De; Drobek, D.; Eyer, L.; Gameiro, J. F.; Gorlova, Nadya; Kamiński, K.; Lampens, P.; Marcos-Arenal, P.; Pápics, P. I.; Vandenbussche, B.; Winckel, H. Van; Stȩślicki, M.; Fagas, M.

doi:10.1093/mnras/stv528

Cited by 129 publications

(157 citation statements)

References 103 publications

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“…Our apparent projected rotation velocity, va sin i = 5.9 ± 0.2 km s −1 is extremely slow compared with the distribution of v sin i for the stars with similar temperatures in the range 7000 T eff 8000 K (Niemczura et al 2015). Their figure 7(e) shows, and their electronic table 3 lists, values of v sin i distributed between 8 and 260 km s −1 , but mostly between 50 and 150 km s −1 (note that they do not take into account macroturbulence, hence their minimum v sin i is overestimated).…”

Section: Rotation Velocity and Magnetic Braking; Ap Starsmentioning

confidence: 58%

“…When we plot our ∆T eff = −461 K in their figure 3(a), it is included in the negative scatter range. Niemczura et al (2015) suggested that the accuracy of their spectroscopic temperatures is supported because the temperatures derived from spectral energy distributions agree well with T eff (SPEC) within a scatter of about ±300 K. According to their suggestion, and from an evaluation of the quality of each method, we consider our atmospheric parameters, T eff , log g and [Fe/H] to be more reliable than those from broadband photometry. This is unsurprising.…”

Section: Atmospheric Parametersmentioning

confidence: 73%

“…The values of microturbulence ξ derived by Niemczura et al (2015) are plotted in their figure 5. Our ξ is consistent with the behaviour of non-chemically peculiar stars at T eff ∼ 7600 K.…”

Section: Atmospheric Parametersmentioning

confidence: 99%

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Spectroscopic and asteroseismic analysis of the remarkable main-sequence A star KIC 11145123

Takada-Hidai

Kurtz

Shibahashi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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A spectroscopic analysis was carried out to clarify the properties of KIC 11145123 -the first main-sequence star with a determination of core-to-surface rotation -based on spectra observed with the High Dispersion Spectrograph (HDS) of the Subaru telescope. The atmospheric parameters (T eff = 7600 K, log g = 4.2, ξ = 3.1 km s −1 and [Fe/H] = −0.71 dex), the radial and rotation velocities, and elemental abundances were obtained by analysing line strengths and fitting line profiles, which were calculated with a 1D LTE model atmosphere. The main properties of KIC 11145123 are: (1) A low [Fe/H] = −0.71 ± 0.11 dex and a high radial velocity of −135.4 ± 0.2 km s −1 . These are remarkable among late-A stars. Our best asteroseismic models with this low [Fe/H] have slightly high helium abundance and low masses of 1.4 M ⊙ . All of these results strongly suggest that KIC 11145123 is a Population II blue straggler; (2) The projected rotation velocity confirms the asteroseismically predicted slow rotation of the star; (3) Comparisons of abundance patterns between KIC 11145123 and Am, Ap, and blue stragglers show that KIC 11145123 is neither an Am star nor an Ap star, but has abundances consistent with a blue straggler. We conclude that the remarkably long 100-d rotation period of this star is a consequence of it being a blue straggler, but both pathways for the formation of blue stragglers -merger and mass loss in a binary system -pose difficulties for our understanding of the exceedingly slow rotation. In particular, we show that there is no evidence of any secondary companion star, and we put stringent limits on the possible mass of any such purported companion through the phase modulation (PM) technique.

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Section: Rotation Velocity and Magnetic Braking; Ap Starsmentioning

confidence: 58%

Section: Atmospheric Parametersmentioning

confidence: 73%

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Spectroscopic and asteroseismic analysis of the remarkable main-sequence A star KIC 11145123

Takada-Hidai

Kurtz

Shibahashi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…This approach has been successfully used in a number of papers in the recent literature (see e.g. Niemczura et al 2015;Catanzaro & Ripepi 2014;Hubrig et al 2014;Doyle et al 2014;Paunzen et al 2014;Catanzaro et al 2015, just to quote some recent work). The website by Fiorella Castelli 2 contains a description of all the improvements of the Kurucz codes and related updates in the input physics performed in the latest years.…”

Section: Caos Spectramentioning

confidence: 99%

Keplerobservations of A–F pre-main-sequence stars in Upper Scorpius: discovery of six new δ Scuti and one γ Doradus stars

Ripepi¹,

Balona²,

Catanzaro³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present light curves and periodograms for 27 stars in the young Upper Scorpius association (age=11 ± 1 Myr) obtained with the Kepler spacecraft. This association is only the second stellar grouping to host several pulsating pre-main sequence (PMS) stars which have been observed from space.From an analysis of the periodograms, we identify six δ Scuti variables and one γ Doradus star. These are most likely PMS stars or else very close to the zero-age main sequence. Four of the δ Scuti variables were observed in short-cadence mode, which allows us to resolve the entire frequency spectrum. For these four stars, we are able to infer some qualitative information concerning their ages. For the remaining two δ Scuti stars, only long-cadence data are available, which means that some of the frequencies are likely to be aliases. One of the stars appears to be a rotational variable in a hierarchical triple system. This is a particularly important object, as it allows the possibility of an accurate mass determination when radial velocity observations become available. We also report on new high-resolution echelle spectra obtained for some of the stars of our sample.

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“…A&A proofs: manuscript no. k0415_v1.1 Niemczura et al (2015); (3) Simbad (Wenger et al 2000); (4) Kepler Input Catalog; (5) 2MASS (Skrutskie et al 2006) the Kepler Eclipsing Binaries Catalog (KEBC; Prša et al 2011;Slawson et al 2011;Kirk et al 2016) 2 . It is usually classified as having a late-A spectral type.…”

Section: Introductionmentioning

confidence: 99%

KIC 4150611: a rare multi-eclipsing quintuple with a hybrid pulsator

Hełminiak

Ukita

Kambe

et al. 2017

A&A

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Aims. We present the results of our analysis of KIC 4150611 (HD 181469) -an interesting, bright quintuple system that includes a hybrid δ Sct/γ Dor pulsator. Four periods of eclipses -94.2, 8.65, 1.52 and 1.43 d -have been observed by the Kepler satellite, and three point sources (A,B, and C) are seen in high angular resolution images. Methods. From spectroscopic observations made with the HIDES spectrograph attached to the 1.88-m telescope of the Okayama Astrophysical Observatory (OAO), for the first time we calculated radial velocities (RVs) of the component B -a pair of G-type stars -and combined them with Kepler photometry in order to obtain absolute physical parameters of this pair. We also managed to directly measure RVs of the pulsator, also for the first time. Additionally, we modelled the light curves of the 1.52 and 1.43-day pairs, and measured their eclipse timing variations (ETVs). We also performed relative astrometry and photometry of three sources seen on the images taken with the NIRC2 camera of the Keck II telescope. Finally, we compared our results with theoretical isochrones. Results. The brightest component Aa is the hybrid pulsator, transited every 94.2 days by a pair of K/M-type stars (Ab1+Ab2), which themselves form a 1.52-day eclipsing binary. The components Ba and Bb are late G-type stars, forming another eclipsing pair with a 8.65 day period. Their masses and radii are M Ba = 0.894 ± 0.010 M ⊙ , R Ba = 0.802 ± 0.044 R ⊙ for the primary, and M Bb = 0.888 ± 0.010 M ⊙ , R Bb = 0.856 ± 0.038 R ⊙ for the secondary. The remaining period of 1.43 days is possibly related to a faint third star C, which itself is most likely a background object. The system's properties are well-represented by a 35 Myr isochrone, basing on which the masses of the pulsator and the 1.52-day pair are M Aa = 1.64(6) M ⊙ , and M Ab,tot = 0.90(13) M ⊙ , respectively. There are also hints of additional bodies in the system.

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Spectroscopic survey of Kepler stars.★ I. HERMES/Mercator observations of A- and F-type stars

Cited by 129 publications

References 103 publications

Spectroscopic and asteroseismic analysis of the remarkable main-sequence A star KIC 11145123

Spectroscopic and asteroseismic analysis of the remarkable main-sequence A star KIC 11145123

Keplerobservations of A–F pre-main-sequence stars in Upper Scorpius: discovery of six new δ Scuti and one γ Doradus stars

KIC 4150611: a rare multi-eclipsing quintuple with a hybrid pulsator

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