2014A&A...572A...7K


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.23CEST00:59:12

2014A&A...572A...7K - Astronomy and Astrophysics, volume 572A, 7-7 (2014/12-1)

The long-period Galactic Cepheid RS Puppis. III. A geometric distance from HST polarimetric imaging of its light echoes.

KERVELLA P., BOND H.E., CRACRAFT M., SZABADOS L., BREITFELDER J., MERAND A., SPARKS W.B., GALLENNE A., BERSIER D., FOUQUE P. and ANDERSON R.I.

Abstract (from CDS):

As one of the most luminous Cepheids in the Milky Way, the 41.5-day RS Puppis is an analog of the long-period Cepheids used to measure extragalactic distances. An accurate distance to this star would therefore help anchor the zero-point of the bright end of the period-luminosity relation. But, at a distance of about 2kpc, RS Pup is too far away for measuring a direct trigonometric parallax with a precision of a few percentage points with existing instrumentation. RS Pup is unique by being surrounded by a reflection nebula whose brightness varies as pulses of light from the Cepheid propagate outward. We present new polarimetric imaging of the nebula obtained with HST/ACS. The derived map of the degree of linear polarization pL allows us to reconstruct the three-dimensional structure of the dust distribution. To retrieve the scattering angle from the pL value, we consider two different polarization models, one based on a Milky Way dust mixture and one assuming Rayleigh scattering. Considering the derived dust distribution in the nebula, we adjust a model of the phase lag of the photometric variations over selected nebular features to retrieve the distance of RS Pup. We obtain a distance of 1910±80pc (4.2%), corresponding to a parallax of π=0.524±0.022mas. The agreement between the two polarization models that we considered is good, but the final uncertainty is dominated by systematics in the adopted model parameters. The distance we obtain is consistent with existing measurements from the literature, but light echoes provide a distance estimate that is not subject to the same systematic uncertainties as other estimators (e.g., the Baade-Wesselink technique). RS Pup therefore provides an important fiducial for calibrating the systematic uncertainties of the long-period Cepheid distance scale.

Abstract Copyright:

Journal keyword(s): stars: individual: RS Puppis - circumstellar matter - techniques: polarimetric - stars: variables: Cepheids - dust, extinction - scattering

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 V* SU Cas cC* 02 51 58.7508894403 +68 53 18.601570075 6.92 6.44 5.80     F5.5III+ 405 1
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5375 1
3 OGLE LMC-CEP-227 cC* 04 52 15.6982549282 -70 14 31.242341027     15.317   14.438 ~ 46 0
4 V* V838 Mon CV* 07 04 04.8222936785 -03 50 50.637499515   15.5   15.18 14.51 M10+B3V 362 0
5 V* VY CMa s*r 07 22 58.32877 -25 46 03.2355 12.01 10.19 7.95     M5Iae 984 0
6 HD 68111 * 08 09 37.3111875383 -36 49 53.604053924   9.34 8.18     G3Ib 12 0
7 V* RS Pup cC* 08 13 04.2157137938 -34 34 42.691837063 8.89 8.00 6.70   5.453 F8Iab 309 1
8 HD 71670 * 08 27 20.7773831419 -34 41 51.974602285   9.18 7.54     K5III 8 0
9 MR 22 PN 10 21 33.826 -58 05 48.26     12.7     A2Ie 101 0
10 NAME Homunculus Nebula ISM 10 45 03.5 -59 41 04           ~ 309 1
11 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2148 0
12 V* AU Mic BY* 20 45 09.5323695486 -31 20 27.241710746   10.05 8.627 9.078 6.593 M1VeBa1 868 0

    Equat.    Gal    SGal    Ecl

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2019.10.23-00:59:12

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