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Related papers: First Images of R Aquarii and its Asymmetric H$_{2…

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We report the first spatially-resolved observations of the spectroscopic binaries lambda Vir and WR 140, which includes the debut of aperture-synthesis imaging with the upgraded three-telescope IOTA interferometer. Using IONIC-3, a new…

Due to the recent dramatic technological advances, infrared interferometry can now be applied to new classes of objects, resulting in exciting new science prospects, for instance, in the area of high-mass star formation. Although…

Acquiring near-infrared K-band (2.2 um) photometry for RR Lyrae variables in globular clusters and nearby galaxies is advantageous since the resulting distances are less impacted by reddening and metallicity. However, K-band photometry for…

Astrophysics of Galaxies · Physics 2015-06-11 Daniel J. Majaess , David G. Turner , Wolfgang P. Gieren

We want to improve knowledge of the structure of the inner few AU of the circumstellar disk around the nearby T Tauri star TW Hya. Earlier studies have suggested the existence of a large inner hole, possibly caused by interactions with a…

Astrophysics · Physics 2009-11-13 Th. Ratzka , Ch. Leinert , Th. Henning , J. Bouwman , C. P. Dullemond , W. Jaffe

Pulsation models are crucial for the interpretation of spectrophotometric and interferometric observations of Mira variables. Comparing predicted and observed spectra is one way of establishing the validity of such models. In this paper, we…

Astrophysics · Physics 2009-11-10 A. Tej , A. Lancon , M. Scholz , P. R. Wood

Context. Stars on the asymptotic giant branch (AGB) are long-period variables that present strong flux variations at almost all wavelengths, including the SiO maser lines. The periods of these variations are of 300-500 days in Mira-type…

A multi-wavelength, multi-scale study of the Mon R2 hub-filament system (HFS) reveals a spiral structure, with the central hub containing more mass than its filaments. ALMA C$^{18}$O(1-0) emission reveals several accreting filaments…

Astrophysics of Galaxies · Physics 2024-12-04 L. K. Dewangan , N. K. Bhadari , A. K. Maity , O. R. Jadhav , Saurabh Sharma , A. Haj Ismail

We describe the time-dependent properties of a new spectroscopically confirmed Mira variable, which was discovered in 2013 as MASTER-Net Optical Transient (OT) J212444.87+321738.3 towards the Cygnus constellation. We have performed…

Solar and Stellar Astrophysics · Physics 2018-05-16 Supriyo Ghosh , Soumen Mondal , Ramkrishna Das , D. P. K. Banerjee , N. M. Ashok , Franz-Josef Hambsch , Somnath Dutta

Multi-epoch Chandra and XMM-Newton observations of the symbiotic system R Aquarii (R Aqr) spanning 22 yr are analysed by means of a reflection model produced by an accretion disc. This methodology helps dissecting the contribution from…

Solar and Stellar Astrophysics · Physics 2024-11-08 D. A. Vásquez-Torres , J. A. Toalá , A. Sacchi , M. A. Guerrero , E. Tejeda , M. Karovska , R. Montez

We present the results of AKARI observations of the O-rich supernova remnant G292.0+1.8 using six IRC and four FIS bands covering 2.7-26.5 um and 50-180 um, respectively. The AKARI images show two prominent structures; a bright equatorial…

We report observations and analysis of flux monitoring of Sagittarius A* at 3-mm wavelength using the OVRO millimeter interferometer over a period of eight days (2002 May 23-30). Frequent phase and flux referencing (every 5 minutes) with…

Astrophysics · Physics 2009-11-10 Jon C. Mauerhan , Mark Morris , Fabian Walter , Frederick K. Baganoff

We present 10' x 50' scan maps around an M supergiant Alpha Ori at 65, 90, 140 and 160 microns obtained with the AKARI Infrared Astronomy Satellite. Higher spatial resolution data with the exact analytic solution permit us to fit the…

We report on the detection of localized off-center emission at 1-4 AU in the circumstellar environment of the young stellar object AB Aurigae. We used closure phase measurements in the near-infrared made at the long baseline interferometer…

Semi-regular variables (SRVs) though closely related to Mira variables, are a less studied class of AGB stars. While asymmetry in the brightness distribution of many Mira variables is fairly well known, it is detected only in a few SRVs.…

Solar and Stellar Astrophysics · Physics 2015-06-22 Tapas Baug , T. Chandrasekhar , Shashikiran Ganesh

We present the results of a 22GHz H2O maser survey toward a new sample of AGB and post-AGB star candidates. Most of the objects are selected for the first time based on the AKARI data, which have high flux sensitivity in the mid-infrared…

Solar and Stellar Astrophysics · Physics 2015-06-15 Bosco Yung , Jun-ichi Nakashima , Hiroshi Imai , Shuji Deguchi , Christian Henkel , Sun Kwok

The subject of micro-variability among Mira stars has received increased attention since DeLaverny et al. (1998) reported short-term brightness variations in 15 percent of the 250 Mira or Long Period Variable stars surveyed using the…

Astrophysics · Physics 2007-05-23 D. E. Mais , D. Richards , R. E. Stencel

We explored an efficient method to identify evolved stars with oxygen-rich envelopes in the late AGB or post-AGB phase of stellar evolution, which include a rare class of objects - the "water fountains". Our method considers the OH and H2O…

Solar and Stellar Astrophysics · Physics 2015-06-22 Bosco Yung , Jun-ichi Nakashima , Christian Henkel

Chandra high-resolution spectra toward eight low-mass Galactic binaries have been analyzed with a photoionization model that is capable of determining the physical state of the interstellar medium. Particular attention is given to the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 E. Gatuzz , J. García , C. Mendoza , T. R. Kallman , M. A. Bautista , T. W. Gorczyca

We present the first results from an ongoing survey for multiplicity among the bright stars using the Navy Precision Optical Interferometer (NPOI). We first present a summary of NPOI observations of known multiple systems, including the…

Solar and Stellar Astrophysics · Physics 2016-11-15 Donald Hutter , Robert Zavala , Christopher Tycner , James Benson , Christian Hummel , Jason Sanborn , Otto G. Franz , Kenneth Johnston

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…