2012A&A...538A..24G


Query : 2012A&A...538A..24G

2012A&A...538A..24G - Astronomy and Astrophysics, volume 538A, 24-24 (2012/2-1)

Thermal infrared properties of classical and type II cepheids. Diffraction limited 10 µm imaging with VLT/VISIR.

GALLENNE A., KERVELLA P. and MERAND A.

Abstract (from CDS):

We present new thermal infrared (IR) photometry and spectral energy distributions (SEDs) of eight classical Cepheids (type I) and three type II Cepheids, using VISIR thermal IR photometric measurements, supplemented with literature data. We used the BURST mode of the instrument to get diffraction-limited images at 8.59, 11.25, and 11.85µm. The SEDs show a IR excess at wavelengths longer than 10µm in ten of the eleven stars. We tentatively attribute these excesses to circumstellar emission created by mass loss from the Cepheids. On the basis of some hypotheses for the dust composition, we estimate a total mass of the envelope ranging from 10–10 to 10–8M. We also detect a spatially extended emission around AX Cir, X Sgr, W Sgr, Y Oph, and U Car, while we do not resolve the circumstellar envelope (CSE) of the other stars. The averaged circumstellar envelope brightnesses relative to the stellar photosphere are α(AX Cir)=13.8±2.5%, α(X Sgr)=7.9±1.4%, α(W Sgr)=3.8±0.6%, α(Y Oph)=15.1±1.4%, and α(U Car)=16.3±1.4% at 8.59µm. With this study, we extend the number of classical Cepheids with detected CSEs from 9 to 14, confirming that at least a large fraction of all Cepheids are experiencing significant mass loss. The presence of these CSEs may also impact the future use of Cepheids as standard candles at near and thermal infrared wavelengths.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: variables: Cepheids - stars: mass-loss - stars: imaging - infrared: stars

Simbad objects: 27

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Number of rows : 27
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 641 2
2 V* T Mon cC* 06 25 12.9996760920 +07 05 08.558582892 8.24 7.20 5.98   4.996 G3Iabv+A0p 458 1
3 V* RS Pup cC* 08 13 04.2157111224 -34 34 42.696447852 8.89 8.51 7.04   5.453 F8Iab 336 0
4 * l Car cC* 09 45 14.8117044917 -62 30 28.450312664   5.09 3.75     G5Iab/b 308 0
5 V* GZ Vel LP* 10 19 36.7507384 -55 01 45.502292   6.146 4.543     K2.5II 55 0
6 V* U Car cC* 10 57 48.1866744768 -59 43 55.883482140 8.31 7.21 6.11   5.073 G5/8Iab 224 0
7 * 75 Leo PM* 11 17 17.4004068 +02 00 38.003295 8.54 6.70 5.18 3.91 2.97 M0III 109 0
8 * e Leo * 11 30 18.8933524920 -03 00 12.598924644 8.14 6.31 4.77     K3+IIIFe-0.5 131 0
9 V* S Mus cC* 12 12 47.0199008472 -70 09 06.439196664 7.58 8.80 8.33 7.39 5.196 F6Ib+B5V 249 0
10 * kap Vir PM* 14 12 53.7453840 -10 16 25.333997 7.00 5.53 4.21 3.14 2.39 K2.5IIIFe-0.5 137 0
11 * 26 Cir cC* 14 52 35.2587595008 -63 48 35.356730796   6.66 5.96   4.993 F8II 133 0
12 * nu. Lib * 15 06 37.5965113128 -16 15 24.546990276 8.70 6.78 5.20     K5-III 92 0
13 V* GH Lup Ce* 15 24 38.3402056752 -52 51 13.897364040 10.03 9.05 7.83     G2Iab 93 0
14 * bet Oph PM* 17 43 28.3526482 +04 34 02.295484 5.150 3.930 2.750 1.96 1.38 K2IIICN0.5 463 0
15 V* X Sgr cC* 17 47 33.6239490288 -27 49 50.835778896 5.84 5.34 4.54 6.03 3.661 F7II 325 0
16 V* Y Oph cC* 17 52 38.7019050072 -06 08 36.874071816 8.62 7.61 6.21     G3Ia 354 0
17 * gam01 Sgr cC* 18 05 01.2264355704 -29 34 48.322222356 5.99 5.47 4.69   3.869 G0Ib/II 338 0
18 V* AC Her pA* 18 30 16.2373118976 +21 52 00.599340000 8.00 7.79 7.01     F4Ibp 325 0
19 V* R Sct RV* 18 47 28.9498974024 -05 42 18.542611800 8.30 6.67 5.20 4.14 3.37 K4/5pec 306 0
20 * kap Pav WV* 18 56 57.0289935240 -67 14 00.581211276   5.08 4.40     G5Iab/b 125 0
21 V* FF Aql cC* 18 58 14.7483041520 +17 21 39.297557628 6.61 6.18 5.38     F6Ib 353 0
22 V* SV Vul cC* 19 51 30.9059845128 +27 27 36.837672012 8.65 9.00 6.74   5.703 F8Ia 416 0
23 * eta Aql cC* 19 52 28.3689223781 +01 00 20.371980515 5.12 4.61 3.80   3.030 F6Iab+B9.8V 652 0
24 * 70 Aql * 20 36 43.6331948352 -02 32 59.836714368   6.475 4.880     K4+IIIBa1 74 0
25 V* X Cyg cC* 20 43 24.1917118680 +35 35 16.077149700 8.69 7.70 6.47   5.241 F7Ib 455 0
26 * 1 Peg PM* 21 22 05.1994953807 +19 48 16.237518964 6.25 5.20 4.09 3.30 2.76 K1III 177 0
27 * del Cep cC* 22 29 10.2626640314 +58 24 54.697613650 4.71 4.35 3.75   3.219 F5Iab:+B7-8 702 0

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2022.05.28-08:41:53

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