Lattices from subfields of Q(&amp;#x03BE;&lt;inf&gt;n&lt;/inf&gt;)

Andrade, Antonio Aparecido de; Alves, C.; Carlos, T.B.

doi:10.1109/its.2006.4433388

Cited by 3 publications

(9 citation statements)

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“…Wang et al (2018), searching archival IUE (International Ultraviolet Explorer) spectra for hot sdO companions to Be stars, found no indication of such in this system. Koubský et al (2010) used NPOI observations from 2005, 2006 to spatially resolve the Aa,Ab pair for the first time at ∆m 700 = 2.9 ± 0.1. Utilizing these observations, along with new spectroscopic data, they determined a combined interferometric and spectroscopic orbit (P = 2.824 yr, a = 17.0 mas, i = 115.…”

Section: Results For Individual Systemsmentioning

confidence: 99%

“…6.1.6. We examined 21 nights of archival NPOI data (2006 -2011) using GRIDFIT, obtaining significant detections ( § 5) on 12 nights during 2006, 2007). We then proceeded to detailed modeling of the data from each of the 12 nights with OYSTER using fixed stellar angular diameters of θ P = 0.3 mas (from the NPOI planning software) and θ S = 0.13 mas, estimated from the component spectral type ("early A") suggested by Horch et al (2020), and stellar radii given by Schmidt-Kaler (1982), along with the nightly ρ and θ values and the average ∆m 700 obtained from GRIDFIT as inputs.…”

Section: Results For Individual Systemsmentioning

confidence: 99%

“…After the first such solution, measurements with residuals larger than 3σ were assigned zero weight, and the weights of the remaining measurements were adjusted following the work of Irwin et al (1996) at each iteration. In the case of β Cep, spectroscopic data taken from the literature (Struve et al 1953;Aerts et al 1994;Hadrava & Harmanec 1996;Stickland & Lloyd 2003;Catanzaro & Leone 2008;Henrichs et al 2013), along with the resolved observations from the INT4 and all the NPOI observations, plus 10 Mark III observations, (Table 4) were utilized, with the visual orbit of Andrade (2006) and the spectroscopic orbit (γ and K 1 only) of Pigulski & Boratyn (1992) as inputs. The application of these procedures resulted in an orbit solution predicting visibilities and closure phases in excellent agreement with the data in most cases (Figure 10).…”

Section: Results For Individual Systemsmentioning

confidence: 99%

“…The SB9 lists system 1310 as a SB1, including the orbital solution of Fitch (1969, P = 10.893 d, e = 0.52), but notes difficulty separating orbital velocities from the variable star pulsations, and that the evidence in this case for a binary nature is "not completely convincing." The MSC likewise lists subsystem (Aa1,Aa2) with these orbital parameters as doubtful, but also lists Aa,Ab with the orbital parameters of Andrade (2006) and lists the AB pair as a CPM system. The INT4 lists resolved speckle observations of the Aa,Ab pair on 59 dates (1971 -2007; 38 mas ≤ ρ ≤ 264 mas).…”

Section: Monmentioning

confidence: 99%

“…We examined 13 nights of archival NPOI data (1997 Jul 03 UT -2002 Jun 24 UT, Table 4) using the program analogous to GRIDFIT within OYSTER to search a grid of 25 mas by 25 mas at 0.3 mas spacings, centered on the position of the secondary star, as predicted by the orbit of Andrade (2006). The χ 2 surfaces in the OYSTER gridfit output for the nights in 1997 and later displayed many closely-spaced local minima in the ρ, θ space of similar depth, and thus the position measurement on those nights was ambiguous.…”

Section: Monmentioning

confidence: 99%

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Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

Hutter

Tycner

Zavala

et al. 2019

ApJS

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We present the results of a multiplicity survey for a magnitude-limited sample of 31 classical Be stars conducted with the Navy Precision Optical Interferometer and the Mark III Stellar Interferometer. The interferometric observations were used to detect companions in ten previously known binary systems. For two of these sources (66 Oph and β Cep) new orbital solutions were obtained, while for a third source (υ Sgr) our observations provide the first direct, visual detection of the hot sdO companion to the Be primary star. Combining our interferometric observations with an extensive literature search, we conclude that an additional four sources (o Cas, 15 Mon, β Lyr, and β Cep) also contain wider binary components that are physical companions to the narrow binaries, thus forming hierarchical multiple systems. Among the sources not previously confirmed as spectroscopic or visual binaries, BK Cam was resolved on a number of nights within a close physical proximity of another star with relative motion possibly suggesting a physical binary. Combining our interferometric observations with an extensive literature search, we provide a detailed listing of companions known around each star in the sample, and discuss the multiplicity frequency in the sample. We also discuss the prospects for future multiplicity studies of classical Be stars by long baseline optical interferometry.

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Section: Results For Individual Systemsmentioning

confidence: 99%

Section: Results For Individual Systemsmentioning

confidence: 99%

Section: Results For Individual Systemsmentioning

confidence: 99%

Section: Monmentioning

confidence: 99%

Section: Monmentioning

confidence: 99%

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Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

Hutter

Tycner

Zavala

et al. 2019

ApJS

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An investigation of the close environment ofβCephei with the VEGA/CHARA interferometer

Nardetto¹,

Mourard²,

Tallon–Bosc

et al. 2010

A&A

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Context. High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star β Cep using the speckle interferometry technique, and features at the limit of resolution (20 milli-arcsec or mas) of the instrument were mentioned that may be due to circumstellar material. β Cep has a magnetic field that might be responsible for a spherical shell or ring-like structure around the star as described by the MHD models. Aims. Using the visible recombiner VEGA installed on the CHARA long-baseline interferometer at Mt. Wilson, we aim to determine the angular diameter of β Cep and resolve its close environment with a spatial resolution up to 1 mas level. Methods. Medium spectral resolution (R = 6000) observations of β Cep were secured with the VEGA instrument over the years 2008 and 2009. These observations were performed with the S1S2 (30 m) and W1W2 (100 m) baselines of the array. Results. We investigated several models to reproduce our observations. A large-scale structure of a few mas is clearly detected around the star with a typical flux relative contribution of 0.23 ± 0.02. Our best model is a co-rotational geometrical thin ring around the star as predicted by magnetically-confined wind shock models. The ring inner diameter is 8.2 ± 0.8 mas and the width is 0.6 ± 0.7 mas. The orientation of the rotation axis on the plane of the sky is PA = 60 ± 1 deg, while the best fit of the mean angular diameter of β Cep gives Φ UD [V] = 0.22 ± 0.05 mas. Our data are compatible with the predicted position of the close companion of β Cep. Conclusions. These results bring additional constraints on the fundamental parameters and on the future MHD and asteroseismological models of the star.

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Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

Storm

Gieren

Fouqué

et al. 2011

A&A

144

204

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Aims. We determine period-luminosity relations for Milky Way Cepheids in the optical and near-IR bands. These relations can be used directly as reference for extra-galactic distance determination to Cepheid populations with solar metallicity, and they form the basis for a direct comparison with relations obtained in exactly the same manner for stars in the Magellanic Clouds, presented in an accompanying paper. In that paper we show that the metallicity effect is very small and consistent with a null effect, particularly in the near-IR bands, and we combine here all 111 Cepheids from the Milky Way, the LMC and SMC to form a best relation. Methods. We employ the near-IR surface brightness (IRSB) method to determine direct distances to the individual Cepheids after we have recalibrated the projection factor using the recent parallax measurements to ten Galactic Cepheids and the constraint that Cepheid distances to the LMC should be independent of pulsation period. Results. We confirm our earlier finding that the projection factor for converting radial velocity to pulsational velocity depends quite steeply on pulsation period, p = 1.550− 0.186 log(P) in disagrement with recent theoretical predictions. We find PL relations based on 70 Milky Way fundamental mode Cepheids of M K = −3.33(±0.09)(log(P) − 1.0) − 5.66(±0.03), W VI = −3.26(±0.11)(log(P) − 1.0) − 5.96(±0.04). Combining the 70 Cepheids presented here with the results for 41 Magellanic Cloud Cepheids which are presented in an accompanying paper, we find M K = −3.30(±0.06)(log(P) − 1.0) − 5.65(±0.02), W VI = −3.32(±0.08)(log(P) − 1.0) − 5.92(±0.03). Conclusions. We delineate the Cepheid PL relation using 111 Cepheids with direct distances from the IRSB analysis. The relations are by construction in agreement with the recent HST parallax distances to Cepheids and slopes are in excellent agreement with the slopes of apparent magnitudes versus period observed in the LMC.

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Lattices from subfields of Q(ξ<inf>n</inf>)

Cited by 3 publications

References 4 publications

Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

An investigation of the close environment ofβCephei with the VEGA/CHARA interferometer

Calibrating the Cepheid period-luminosity relation from the infrared surface brightness technique

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