Query : 2011A&A...527A..51G

2011A&A...527A..51G - Astronomy and Astrophysics, volume 527A, 51-51 (2011/3-1)

Spatially extended emission around the cepheid RS Puppis in near-infrared hydrogen lines. Adaptive optics imaging with VLT/NACO.


Abstract (from CDS):

It has been recently discovered that Cepheids harbor circumstellar envelopes (CSEs). RS Pup is the Cepheid that presents the most prominent circumstellar envelope known, the origin of which is not yet understood. Our purpose is to estimate the flux contribution of the CSE around RS Pup at the one arcsecond scale (∼2000AU) and to investigate its geometry, especially regarding asymmetries, to constrain its physical properties. We obtained near-infrared images in two narrow band filters centered on λ=1.644 and 2.180µm (NB_1.64 and IB_2.18, respectively) that comprise two recombination lines of hydrogen: the 12-4 and 7-4 (Brackett γ) transitions, respectively. We used NACO's cube mode observations in order to improve the angular resolution with the shift-and-add technique, and to qualitatively study the symmetry of the spatially extended emission from the CSE with a statistical study of the speckle noise. We probably detect at a 2σ level an extended emission with a relative flux (compared with the star in the same filter) of 38±17% in the NB_1.64 filter and 24±11% in the IB_2.18 filter. This emission is centered on RS Pup and does not present any detectable asymmetry. We attribute the detected emission to the likely presence of an hydrogen envelope surrounding the star.

Abstract Copyright:

Journal keyword(s): stars: variables: Cepheids - circumstellar matter - instrumentation: adaptive optics - atmospheric effects

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 * del Phe PM* 01 31 15.1047497 -49 04 21.730837   4.918 3.935     G8.5IIIb 120 0
2 * alf Eri Be* 01 37 42.84548 -57 14 12.3101 -0.36 0.30 0.46 0.49 0.60 B6Vpe 457 0
3 V* RS Pup cC* 08 13 04.2157111224 -34 34 42.696447852 8.89 8.51 7.04   5.453 F8Iab 337 0
4 HD 74417 * 08 42 37.9455849000 -37 22 58.539543708   9.16 7.62     K3III 11 0

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