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We present sub-milliarcseond resolution imaging and modeling of two nearby rapid rotators Alpha Cephei and Alpha Ophiuchi, obtained with the CHARA array - the largest optical/IR interferometer in the world. Incorporating a gravity darkening…

We have imaged the M2Iab supergiant star Alpha Ori at 11.7 micron and 17.9 micron using the Hale 5-m telescope and an array camera with sub-arcsecond angular resolution. Our images reveal the circumstellar dust shell extending out to…

Astrophysics · Physics 2009-10-30 S. A. Rinehart , T. L. Hayward , J. R. Houck

We present measurements of fundamental astrophysical properties of nearby, low-mass, K- and M-dwarfs from our DISCOS survey (DIameterS of COol Stars). The principal goal of our study is the determination of linear radii and effective…

In this paper we present a high-resolution spectroscopic analysis of the chemically peculiar star HD207561. During a survey programme to search for new roAp stars in the Northern hemisphere, Joshi et al. (2006) observed significant…

Solar and Stellar Astrophysics · Physics 2015-06-05 S. Joshi , E. Semenko , P. Martinez , M. Sachkov , Y. C. Joshi , S. Seetha , N. K. Chakradhari , D. L. Mary , V. Girish , B. N. Ashoka

We have executed a survey of nearby, main sequence A, F, and G-type stars with the CHARA Array, successfully measuring the angular diameters of fortyfour stars with an average precision of ~ 1.5%. We present new measures of the bolometric…

We present the results of long-baseline optical interferometry observations using the Precision Astronomical Visual Observations (PAVO) beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array to measure the angular…

Spectroscopy is a powerful tool for detecting variability in the rapidly oscillating Ap (roAp) stars. The technique requires short integrations times and high resolution, and so is limited to only a few telescopes and instruments. To test…

Solar and Stellar Astrophysics · Physics 2020-09-09 D. L. Holdsworth , E. Brunsden

Alpha Centauri A is the closest solar-type star to the Sun and offers an excellent opportunity to detect the thermal emission of a mature planet heated by its host star. The MIRI coronagraph on JWST can search the 1-3 AU (1"-2") region…

We have obtained H-band interferometric observations of three galactic red supergiant stars using the MIRC instrument on the CHARA array. The targets include AZ Cyg, a field RSG and two members of the Per OB1 association, RS Per and T Per.…

Solar and Stellar Astrophysics · Physics 2009-02-17 L. L. Kiss , J. D. Monnier , T. R. Bedding , P. Tuthill , M. Zhao , M. J. Ireland , T. A. ten Brummelaar

We present time-series spectroscopy of the rapidly oscillating Ap star HR 3831. This star has a dominant pulsation period of 11.7 minutes and a rotation period of 2.85 days. We have analysed 1400 intermediate-resolution spectra of the…

Astrophysics · Physics 2015-06-24 I. K. Baldry , T. R. Bedding

Using Georgia State University's CHARA Array interferometer, we measured angular diameters for 25 giant stars, six of which host exoplanets. The combination of these measurements and Hipparcos parallaxes produce physical linear radii for…

We present interferometric observations of 7 main-sequence and 3 giant stars with spectral types from B2 to F6 using the PAVO beam combiner at the CHARA array. We have directly determined the angular diameters for these objects with an…

We present a novel approach to model the nearby stars Alpha Cen A & B and Procyon A using asteroseismic and interferometric constraints. Using the VINCI instrument installed at the VLT Interferometer (VLTI), the angular diameters of the…

Astrophysics · Physics 2007-05-23 P. Kervella , F. Thevenin , P. Morel , G. Berthomieu , J. Provost , P. Borde , D. Segransan

We present angular diameters for 42 luminosity class I stars and 32 luminosity class II stars that have been interferometrically determined with the Palomar Testbed Interferometer. Derived values of radius and effective temperature are…

Astrophysics · Physics 2015-05-13 G. T. van Belle , M. J. Creech-Eakman , A. Hart

Using the Navy Precision Optical Interferometer, we measured the angular diameters of 10 stars that have previously measured solar-like oscillations. Our sample covered a range of evolutionary stages but focused on evolved subgiant and…

Solar and Stellar Astrophysics · Physics 2015-06-18 Ellyn K. Baines , J. Thomas Armstrong , Henrique R. Schmitt , James A. Benson , R. T. Zavala , Gerard T. van Belle

We combine results from interferometry, asteroseismology and spectroscopic analyses to determine accurate fundamental parameters (mass, radius and effective temperature) of 10 bright solar-type stars covering the H-R diagram from spectral…

Solar and Stellar Astrophysics · Physics 2015-05-14 H. Bruntt

The apparent size of stars is a crucial benchmark for fundamental stellar properties such as effective temperatures, radii and surface gravities. While interferometric measurements of stellar angular diameters are the most direct method to…

Solar and Stellar Astrophysics · Physics 2014-05-23 L. Casagrande , L. Portinari , I. S. Glass , D. Laney , V. Silva Aguirre , J. Datson , J. Andersen , B. Nordström , J. Holmberg , C. Flynn , M. Asplund

We present interferometric observations of six O-type stars that were made with the Precision Astronomical Visible Observations (PAVO) beam combiner at the Center for High Angular Resolution Astronomy (CHARA) Array. The observations include…

Solar and Stellar Astrophysics · Physics 2018-12-19 Kathryn D. Gordon , Douglas R. Gies , Gail H. Schaefer , Daniel Huber , Michael Ireland , D. John Hillier

The Ap star HD3980 appears to be a promising roAp candidate based on its fundamental parameters, leading us to search for rapid pulsations with the VLT UV-Visual Echelle Spectrograph (UVES). A precise Hipparcos parallax and estimated…

Astrophysics · Physics 2009-11-13 V. G. Elkin , D. W. Kurtz , L. M. Freyhammer , S. Hubrig , G. Mathys