Co-phasing of segmented mirrors using Dispersed Rayleigh Interferometry in the presence of background star

2010 ◽  
Author(s):  
Shanshan Wang ◽  
Qiudong Zhu ◽  
Tao Huang
Keyword(s):  
Rayleigh Interferometry ◽  
Background Star

scholarly journals Quaternary Diffusion Coefficients in a Protein−Polymer−Salt−Water System Determined by Rayleigh Interferometry

2009 ◽  
Vol 113 (40) ◽  
pp. 13446-13453 ◽  
Author(s):  
Onofrio Annunziata ◽  
Alessandro Vergara ◽  
Luigi Paduano ◽  
Roberto Sartorio ◽  
Donald G. Miller ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Salt Water ◽  
Water System ◽  
Protein Polymer ◽  
Rayleigh Interferometry

scholarly journals Ongoing astrometric microlensing events of two nearby stars

2018 ◽  
Vol 615 ◽  
pp. L11 ◽  
Author(s):  
J. Klüter ◽  
U. Bastian ◽  
M. Demleitner ◽  
J. Wambsganss
Keyword(s):  
Prior Knowledge ◽  
Gravitational Lensing ◽  
Proper Motion ◽  
Absolute Magnitude ◽  
Stellar Objects ◽  
Lens Position ◽  
Data Release ◽  
Nearby Stars ◽  
Excellent Tool ◽  
Background Star

Context. Astrometric microlensing is an excellent tool to determine the mass of stellar objects. By measuring the astrometric shift of a background source star in combination with precise predictions of its unlensed position and of the lens position, gravitational lensing allows to one determine the mass of the lensing star with a precision of 1%, independently of any prior knowledge. Aims. Making use of the recently published Gaia Data Release 2 (Gaia DR2) we predict astrometric microlensing events by fore-ground stars of high proper motion passing by a background star in the coming years. Methods. We compile a list of approximately 148 000 high-proper-motion stars within Gaia DR2 with µtot > 150 mas yr−1. We then search for background stars close to their paths and calculate the dates and separations of the closest approaches. Using color and absolute magnitude, we determine approximate masses of the lenses. Finally, we calculate the expected astrometric shifts and magnifications of the predicted events. Results. We detect two ongoing microlensing events by the high-proper-motion stars Luyten 143-23 and Ross 322 and predict closest separations of (108.5 ± 1.4) mas in July 2018 and (125.3 ± 3.4) mas in August 2018, respectively. The respective expected astrometric shifts are (1.74 ± 0.12) mas and (0.76 ± 0.06) mas. Furthermore, Luyten 143-23 will pass by another star in March 2021 with a closest separation of (280.1 ± 1.1) mas, which results in an expected shift of (0.69 ± 0.05) mas.

scholarly journals Evidence That the Directly Imaged Planet HD 131399 Ab Is a Background Star

2017 ◽  
Vol 154 (6) ◽  
pp. 218 ◽  
Author(s):  
Eric L. Nielsen ◽  
Robert J. De Rosa ◽  
Julien Rameau ◽  
Jason J. Wang ◽  
Thomas M. Esposito ◽  
...  
Keyword(s):  
Background Star

scholarly journals Microlensing Searches for Exoplanets

Geosciences ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 365 ◽  
Author(s):  
Yiannis Tsapras
Keyword(s):  
Future Prospects ◽  
Theoretical Concepts ◽  
Gravitational Microlensing ◽  
The Future ◽  
Gravitational Influence ◽  
Background Star

Gravitational microlensing finds planets through their gravitational influence on the light coming from a more distant background star. The presence of the planet is then inferred from the tell-tale brightness variations of the background star during the lensing event, even if no light is detectable from the planet or the host foreground star. This review covers fundamental theoretical concepts in microlensing, addresses how observations are performed in practice, the challenges of obtaining accurate measurements, and explains how planets reveal themselves in the data. It concludes with a presentation of the most important findings to-date, a description of the method’s strengths and weaknesses, and a discussion of the future prospects of microlensing.

scholarly journals VLT Spectra of the Companion Candidate Cha Hα 5/cc 1

2003 ◽  
Vol 211 ◽  
pp. 309-310
Author(s):  
Ralph Neuhäuser ◽  
Eike Guenther ◽  
Wolfgang Brandner
Keyword(s):  
Infrared Spectra ◽  
Brown Dwarf ◽  
Background Star

We obtained optical and infrared spectra of Cha Hα 5/cc 1, a faint possibly sub-stellar companion candidate next to the M6-type brown dwarf candidate Cha Hα 5 in Cha I, using FORS1 and ISAAC at the VLT. The VRIJHK colors of Cha Hα 5/cc 1 are consistent with either an L-type companion or a K-type background giant. Our spectra show that the companion candidate actually is a background star.

Sign in / Sign up

Export Citation Format

Share Document