2017A&A...608A.124M


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.12CET03:16:05

2017A&A...608A.124M - Astronomy and Astrophysics, volume 608A, 124-124 (2017/12-1)

Spectroscopic and photometric oscillatory envelope variability during the S Doradus outburst of the luminous blue variable R71.

MEHNER A., BAADE D., GROH J.H., RIVINIUS T., HAMBSCH F.-J., BARTLETT E.S., ASMUS D., AGLIOZZO C., SZEIFERT T. and STAHL O.

Abstract (from CDS):

Context. Luminous blue variables (LBVs) are evolved massive stars that exhibit instabilities that are not yet understood. Stars can lose several solar masses during this evolutionary phase. The LBV phenomenon is thus critical to our understanding of the evolution of the most massive stars.
Aims. The LBV R71 in the Large Magellanic Cloud is presently undergoing an S Doradus outburst, which started in 2005. To better understand the LBV phenomenon, we determine the fundamental stellar parameters of R71 during its quiescence phase. In addition, we analyze multiwavelength spectra and photometry obtained during the current outburst.
Methods. We analyzed pre-outburst CASPEC spectra from 1984-1997, EMMI spectra in 2000, UVES spectra in 2002, and FEROS spectra from 2005 with the radiative transfer code CMFGEN to determine the fundamental stellar parameters of the star. A spectroscopic monitoring program with VLT X-shooter since 2012 secured visual to near-infrared spectra throughout the current outburst, which is well-covered by ASAS and AAVSO photometry. Mid-infrared images and radio data were also obtained.
Results. During quiescence, R71 has an effective temperature of Teff=15500K and a luminosity of log(L*/L)=5.78. We determine its mass-loss rate to 4.0x10–6M/yr. We present the spectral energy distribution of R71 from the near-ultraviolet to the mid-infrared during its present outburst. Semi-regular oscillatory variability in the light curve of the star is observed during the current outburst. Absorption lines develop a second blue component on a timescale of twice that length. The variability may consist of one (quasi-)periodic component with P∼425/850d with additional variations superimposed.
Conclusions. R71 is a classical LBV, but this star is at the lower luminosity end of this group. Mid-infrared observations suggest that we are witnessing dust formation and grain evolution. During its current S Doradus outburst, R71 occupies a region in the HR diagram at the high-luminosity extension of the Cepheid instability strip and exhibits similar irregular variations as RV Tau variables. LBVs do not pass the Cepheid instability strip because of core evolution, but they develop comparable cool, low-mass, extended atmospheres in which convective instabilities may occur. As in the case of RV Tau variables, the occurrence of double absorption lines with an apparent regular cycle may be due to shocks within the atmosphere and period doubling may explain the factor of two in the lengths of the photometric and spectroscopic cycles.

Abstract Copyright: © ESO, 2017

Journal keyword(s): stars: massive - stars: variables: S Doradus - stars: mass-loss - stars: individual: R71 - stars: individual: R71

Simbad objects: 29

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Number of rows : 29

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10574 1
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9102 1
3 HD 268835 s*b 04 56 47.0796207119 -69 50 24.767090336 10.21 10.77 10.63 10.72 10.16 B8[e] 96 0
4 HD 269006 s*b 05 02 07.3944119328 -71 20 13.118657760 9.93 10.60 10.55 10.43 10.38 LBV 230 0
5 HD 268939 s?b 05 04 14.9088131616 -67 15 05.254533820   11.07 11.03 11.12   B:Ie 32 0
6 LHA 120-S 18 Em* 05 05 53.9807776877 -68 10 50.539871441   12.06 11.903 12.01 11.821 B3Ie 16 0
7 HD 269050 s*b 05 07 20.4220012957 -68 32 08.572354312 10.593 11.581 11.54 11.46 11.55 B0Ia(e?) 61 0
8 HD 269128 s*b 05 10 22.7894940469 -68 46 23.818379498 9.77 10.52 10.412 10.29 10.268 B2.5Ieq 92 0
9 HD 269216 Em* 05 13 30.7809925326 -69 32 23.648218945 10.227 10.84 11.123 10.96 10.573 OBe 38 0
10 HD 269227 WR* 05 13 54.2798782060 -69 31 46.659015245 11.429 11.98 11.918 12.13 10.557 WN9/10+M2Ia 147 0
11 HD 269321 s*b 05 17 56.0740517156 -69 16 03.806870993 10.28 10.93 10.84 10.53 10.342 B5Iae 59 0
12 V* S Dor sg* 05 18 14.3572490675 -69 15 01.148131817 9.08 10.39 10.25 9.74 9.14 A5Iaeq 337 0
13 HD 269445 WR* 05 22 59.7854939490 -68 01 46.634598597 10.79 11.77 11.520 11.41 10.979 Ofpe/WN9 105 0
14 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14338 1
15 HD 269582 WR* 05 27 52.6620154151 -68 59 08.486272253 12.206 10.818 11.093 12.70 11.234 WN10h 92 0
16 HD 269662 sg* 05 30 51.4755593461 -69 02 58.591230109 10.23 10.52 10.28 10.40 10.390 A0Ia 89 0
17 HD 269700 s*b 05 31 52.2818792698 -68 32 38.856584550 9.71 10.56 10.54 10.38 10.38 B1.5Iaeq 76 0
18 HD 37836 Em* 05 35 16.6331678655 -69 40 38.439677992 9.87 10.736 10.599 10.73 10.164 B0e(q) 72 0
19 CPD-69 402 s*b 05 35 27.9799035534 -69 16 10.561668692   12.28 12.24 11.1   B3I 279 1
20 SN 1987A SN* 05 35 28.020 -69 16 11.07   4.75 4.81     SN.IIPec 4384 2
21 HD 269858 s*b 05 36 43.6942807271 -69 29 47.449383685   10.24 10.15 9.95 9.05 LBV 261 2
22 HD 269859 s*b 05 36 47.1879908475 -69 29 52.088446369 9.940 10.761 10.730 11.06   B1Ia 46 1
23 CPD-69 463 s*y 05 38 51.6167474749 -69 08 07.314653596 11.93 12.45 12.014     F7Ia 77 1
24 RMC 149 * 05 39 58.7451762905 -69 44 04.070717721 11.645 12.442 12.517   12.227 O8.5II((f)) 30 0
25 HD 38489 s*b 05 40 13.3208554964 -69 22 46.485104413 11.236 12.295 11.93 11.79 10.891 B[e] 81 1
26 SK -69 279 Em* 05 41 44.6557001998 -69 35 14.904660652 12.079 12.787 12.842 13.03 12.619 OB 42 0
27 * eta Car Em* 10 45 03.5455050 -59 41 03.951060 6.37 7.034 6.21 4.90 4.41 OBepec 2150 0
28 V* AG Car WR* 10 56 11.5779283438 -60 27 12.809532379 7.00 7.57 6.96 7.73   WN11h 580 0
29 * P Cyg s*b 20 17 47.2020844 +38 01 58.552724 4.66 5.24 4.82 4.28 4.02 B1-2Ia-0ep 1126 1

    Equat.    Gal    SGal    Ecl

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2019.11.12-03:16:05

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