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We present the first results from an extended survey of the Andromeda galaxy (M31) using 41.1 h of observations by Spitzer-IRAC at 3.6 and 4.5$\,\mu$m. This survey extends previous observations to the outer disc and halo, covering total…

We present half-light radius measurements for the dwarf satellites of Andromeda, based on multi-epoch imaging from the Isaac Newton Telescope (INT) Monitoring Survey of Local Group dwarf galaxies. This analysis is conducted within a larger…

Astrophysics of Galaxies · Physics 2025-11-05 Hedieh Abdollahi

Using a new grism at the Keck Interferometer, we obtained spectrally dispersed (R ~ 230) interferometric measurements of the Mira star R Vir. These data show that the measured radius of the emission varies substantially from 2.0-2.4…

We present the first speckle interferometric observations of R CrB, the prototype of a class of peculiar stars which undergo irregular declines in their visible light curves. The observations were carried out with the 6m telescope at the…

We present updated parameters for the star HD 209458 and its transiting giant planet. The stellar angular diameter $\theta$=0.2254$\pm$0.0017 mas is obtained from the average ratio between the absolute flux observed with the Hubble Space…

Solar and Stellar Astrophysics · Physics 2017-07-05 Carlos del Burgo , Carlos Allende Prieto

We present mid-infrared interferometric observations of the Herbig Ae star R CrA obtained with MIDI at the VLTI using several projected baselines in the UT2-UT3 configuration. The observations show resolved circumstellar emission in the…

Astrophysics · Physics 2007-05-23 S. Correia , R. Koehler , G. Meeus , H. Zinnecker

System parameters are re-determined: $M_1=0.86\pm0.18M\odot$, $M_2=0.103\pm0.022M\odot$, $A=1.508\pm 0.100\times 10^{10}$cm, and $i=69\pm3^{\circ}$. The secondary component is a semi-degenerate helium star loosing mass at a rate $\dot…

Solar and Stellar Astrophysics · Physics 2023-12-29 J. Smak

We present images and a color-magnitude diagram for And V, a new dwarf spheroidal companion to M31 that was found using a digital filtering technique applied to 1550 square degrees of the second Palomar Sky Survey. And V resolves into stars…

Astrophysics · Physics 2009-10-30 Taft E. Armandroff , James E. Davies , George H. Jacoby

The photospheric radius is one of the fundamental parameters governing the radiative equilibrium of a star. We report new observations of the nearest solar-type stars Alpha Centauri A (G2V) and B (K1V) with the VLTI/PIONIER optical…

Solar and Stellar Astrophysics · Physics 2017-01-25 P. Kervella , L. Bigot , A. Gallenne , F. Thévenin

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 use near-infrared interferometric data coupled with trigonometric parallax values and spectral energy distribution fitting to directly determine stellar radii, effective temperatures, and luminosities for the exoplanet host stars 61 Vir,…

We present high spectral resolution aperture-synthesis imaging of the red supergiant Antares (alpha Sco) in individual CO first overtone lines with VLTI/AMBER. The reconstructed images reveal that the star appears differently in the blue…

Solar and Stellar Astrophysics · Physics 2015-06-15 Keiichi Ohnaka , Karl-Heinz Hofmann , Dieter Schertl , Gerd Weigelt , Carlo Baffa , Alain Chelli , Romain Petrov , Sylvie Robbe-Dubois

Based on CHARA Array measurements, we present the angular diameters of 23 nearby, main- sequence stars, ranging from spectral type A7 to K0, five of which are exoplanet host stars. We derive linear radii, effective temperatures, and…

Debate over the planet occurrence rates around intermediate-mass stars has hinged on the accurate determination of masses of evolved stars, and has been exacerbated by a paucity of reliable, directly-measured fundamental properties for…

We present new BV CCD photometry, light curves, and ephemerides for 9 previously known, 29 newly detected RR Lyrae variables and one newly detected variable of an unknown type in the globular cluster M75. The photometry used for the…

Astrophysics · Physics 2009-11-07 T. M. Corwin , M. Catelan , H. A. Smith , J. Borissova , F. R. Ferraro , W. S. Raburn

The Andromeda galaxy was observed by the Guoshoujing Telescope (GSJT, formly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST) during the 2009 commissioning phase. Due to the absence of standard stars for flux…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Hu Zou , Yanbin Yang , Tianmeng Zhang , Jun Ma , Xu Zhou , Ali Luo , Haotong Zhang , Zhongrui Bai , Yongheng Zhao

We study Luminous Blue Variable (LBV) candidate J004341.84+411112.0 in the Andromeda galaxy. We present optical spectra of the object obtained with the 6-m telescope of SAO RAS. The candidate shows typical LBV features in its spectra: broad…

Solar and Stellar Astrophysics · Physics 2021-11-19 A. Sarkisyan , O. Sholukhova , S. Fabrika , A. Valeev , A. Valcheva , P. Nedialkov , A. Tatarnikov

BVR photometry of a recently identified RS CVn binary star HD61396, carried out during 2001, is presented. The new photometry reveal significant evolution in the shape and amplitude of light curve when compared with those reported earlier…

Astrophysics · Physics 2009-11-10 Sudhanshu Barway , S. K. Pandey , Padmakar Singh Parihar

Accurate determination of the stellar atmospheric parameters of RR Lyrae stars (RRLs) requires short individual exposures of the spectra to mitigate pulsation effects. We present improved template matching methods to determine the stellar…

Solar and Stellar Astrophysics · Physics 2024-04-25 Jiangtao Wang , Jianrong Shi , Jianning Fu , Weikai Zong , Chunqian Li