J/AJ/156/148 Multiwavelength photometry of RCB stars (Montiel+, 2018)
The double dust envelopes of R Coronae Borealis stars.
Montiel E.J., Clayton G.C., Sugerman B.E.K., Evans A.,
Garcia-Hernandez D.A., Kameswara Rao N., Matsuura M., Tisserand P.
<Astron. J., 156, 148-148 (2018)>
=2018AJ....156..148M 2018AJ....156..148M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, supergiant ; Stars, variable ; Photometry, UBVRIJKLMNH ;
Stars, distances ; Effective temperatures ; Stars, diameters
Keywords: circumstellar matter - dust, extinction - stars: evolution -
stars: mass loss
Abstract:
The study of extended, cold dust envelopes surrounding R Coronae Borealis
(RCB) stars began with their discovery by the Infrared Astronomical
Satellite. RCB stars are carbon-rich supergiants characterized by their
extreme hydrogen deficiency and their irregular and spectacular declines
in brightness (up to 9 mag). We have analyzed new and archival Spitzer
Space Telescope and Herschel Space Observatory data of the envelopes
of seven RCB stars to examine the morphology and investigate the origin
of these dusty shells. Herschel, in particular, has revealed the first-ever
bow shock associated with an RCB star with its observations of SU Tauri.
These data have allowed the assembly of the most comprehensive spectral
energy distributions (SEDs) of these stars with multiwavelength data from
the ultraviolet to the submillimeter. Radiative transfer modeling of
the SEDs implies that the RCB stars in this sample are surrounded by
an inner warm (up to 1200 K) and an outer cold (up to 200 K) envelope.
The outer shells are suggested to contain up to 10-3 M☉ of dust
and have existed for up to 105 years depending on the expansion rate
of the dust. This age limit indicates that these structures have most
likely been formed during the RCB phase.
Description:
We have combined multiwavelength observations, which range from the UV
to the submillimeter, in order to construct the most comprehensive
spectral energy distributions (SEDs) of our sample R Coronae Borealis
(RCB) stars. Photometry was done on the Spitzer and Herschel images in
order to generate SEDs for the stars in our sample. Many different
programs have been written to perform automated aperture and PSF
photometry. We used the automated aperture routine Source Extractor
(SExtractor; Bertin & Arnouts 1996A&AS..117..393B 1996A&AS..117..393B). The power of
SExtractor is in its many tunable parameters that allow the user to
maximize the program to perform photometry on their desired objects,
whether they be point source or extended. SExtractor also provides robust
post-run ancillary products such as residual, background, object, and
aperture images in addition to performing aperture photometry on any
given input images.
We performed Monte Carlo radiative transfer (MCRT) modeling of the SEDs
for the stars in our sample to better constrain the morphology and physical
parameters of the dust surrounding these objects. We used the fully 3D
MOnte CArlo SimulationS of Ionized Nebulae (MOCASSIN; version 2.02.70)
code (Ercolano et al. 2003MNRAS.340.1136E 2003MNRAS.340.1136E, 2005MNRAS.362.1038E 2005MNRAS.362.1038E,
2008ApJS..175..534E 2008ApJS..175..534E)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 9 Stellar properties and new observations
of sample R Coronae Borealis (RCB) and
hydrogen-deficient (HdC) stars
table2.dat 36 30 MV Sgr photometry
table3.dat 36 24 R CrB photometry
table4.dat 36 31 RY Sgr photometry
table5.dat 36 29 SU Tau photometry
table6.dat 36 33 UW Cen photometry
table7.dat 36 26 V854 Cen photometry
table8.dat 36 27 V CrA photometry
table9.dat 36 18 V605 Aql photometry
table10.dat 36 22 HD 173409 photometry
table11.dat 40 14 Derived MOnte CArlo SimulationS of Ionized
Nebulae (MOCASSIN) properties and measured
outer radii
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/353/287 : The R CrB stars (Asplund+, 2000)
J/A+A/466/L1 : VLTI observations of RY Sgr (Leao+, 2007)
J/AJ/134/1877 : Spectropolarimetry of R CrB in 1998-2003 (Kawabata+, 2007)
J/AcA/59/335 : VI light curves of LMC R CBr stars (Soszynski+, 2009)
J/A+A/539/A51 : Catalogue enriched with R CrB stars (Tisserand, 2012)
J/MNRAS/482/4174 : Heliocentric radial velocities of R CrB (Feast+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Star name
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 34 F5.2 arcsec DEs Arcsecond of Declination (J2000)
36- 39 F4.1 mag Vmag [5.8/12]? Maximum Johnson V band magnitude
41- 45 F5.2 kpc Dist [1.4/11.5]? Modeled distance
46 A1 --- n_Dist [c] Note on Dist (1)
48- 51 F4.2 kpc DistG [1.31/9.14]? Gaia DR2 (Cat. I/345) distance
53- 56 F4.2 kpc e_DistG [0.18/4.5]? Lower limit uncertainty in DistG
58- 63 F6.2 kpc E_DistG [0.24/275]? Upper limit uncertainty in DistG
64 A1 --- n_DistG [b] Note on DistG (2)
66- 70 I5 Lsun Lum [5200/11760]? Modeled luminosity
71 A1 --- n_Lum [c] Note on Lum (1)
73- 77 I5 K Teff [6250/16000]? Effective temperature
79- 83 A5 --- Obs Source(s) of observation (3)
85- 86 I2 --- Tab [2/10] Number of the table containing
multiwavelength photometry
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Note (1): Note as follows:
c = The HD 173409 SED was not modeled in this work (see Section 5.8.3).
Note (2): Note as follows:
b = No parallax in the Gaia DR2 (Cat. I/345).
Note (3): Source of observation as follows:
M = MIPS;
P = PACS;
S = SPIRE.
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Byte-by-byte Description of file: table[23456789].dat table10.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Band Band
19 A1 --- l_Flux [<] 3σ upper limit flag on Flux
20- 27 E8.3 Jy Flux [3.21e-05/54] Flux
29- 36 E8.3 Jy e_Flux [1.5e-05/8.2]? Uncertainty in Flux
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
10- 16 E7.3 cm Rin [3.25e+14/1e+18] Inner radius from MOCASSIN
modeling
18- 24 E7.3 cm Rout [9.45e+15/1e+19] Outer radius from MOCASSIN
modeling
26- 32 E7.3 Msun Mdust [7.59e-08/0.00514] Dust mass from MOCASSIN modeling
34- 40 E7.3 cm RoutM [4.01e+17/1.23e+19]? Measured outer radius
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 13-Mar-2019