2016AJ....151..108E


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.03CET10:48:03

2016AJ....151..108E - Astron. J., 151, 108 (2016/April-0)

Resolved companions of Cepheids: testing the candidates with X-ray observations.

EVANS N.R., PILLITTERI I., WOLK S., KAROVSKA M., TINGLE E., GUINAN E., ENGLE S., BOND H.E., SCHAEFER G.H. and MASON B.D.

Abstract (from CDS):

We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥".) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than ". (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥". or 4000 au.

Abstract Copyright:

Journal keyword(s): binaries: general - stars: formation - stars: massive - stars: variables: Cepheids

Nomenclature: Table 2: [EPW2016] a CCC N, [EPW2016] A CCC N, [EPW2016] VNNN CCC N, N=30.

Simbad objects: 51

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Number of rows : 51

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 [EPW2016] V440 Per 1 * 02 23 50.70 +55 21 59.7     15.72   14.51 ~ 1 0
2 V* V440 Per cC* 02 23 51.7443033534 +55 21 53.502365644 7.76 7.120 6.291     F8Ib-II 173 0
3 [EPW2016] V440 Per 2 * 02 23 52.70 +55 21 46.5     13.83   12.82 ~ 1 0
4 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 619 2
5 Cl Melotte 20 OpC 03 26 42 +48 48.0           ~ 769 0
6 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15206 1
7 * bet Dor cC* 05 33 37.5125319201 -62 29 23.323100433 5.13 4.58 3.76 3.55 3.12 F8/G0Ib 352 0
8 M 42 HII 05 35 17.3 -05 23 28           ~ 3777 0
9 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1059 2
10 * l Car cC* 09 45 14.8112246 -62 30 28.451894   4.33 3.40     G5Iab/b 295 1
11 [EPW2016] l Car 1 * 09 45 15.30 -62 30 09.5     15.21   14.12 ~ 1 0
12 [EPW2016] S Mus 1 * 12 12 46.90 -70 09 11.3     17.94   16.38 ~ 1 0
13 V* S Mus cC* 12 12 47.0194644681 -70 09 06.436474127 7.58 8.80 8.33 7.39 5.196 F6Ib+B5V 241 0
14 [EPW2016] R Cru 2 * 12 23 36.5482245205 -61 38 07.542770953     17.94   16.49 ~ 1 0
15 [EPW2016] R Cru 1 * 12 23 36.7797143270 -61 37 40.737701554     16.28   15.11 ~ 2 0
16 V* R Cru cC* 12 23 37.6883962336 -61 37 44.856977549 7.41 7.00 6.42     F7Ib/II 144 0
17 [EPW2016] R Mus 1 * 12 42 04.30 -69 24 21.5     15.68   14.51 ~ 1 0
18 V* R Mus cC* 12 42 05.0256100705 -69 24 27.196561465 7.65 7.11 6.33   5.499 F7Ib 150 0
19 V* S Cru cC* 12 54 21.9972794334 -58 25 50.214605143 7.94 7.34 6.58   5.730 F7Ib/II 175 0
20 [EPW2016] S Cru 2 * 12 54 22.50 -58 25 39.0     17.90   16.35 ~ 1 0
21 [EPW2016] S Cru 1 * 12 54 23.60 -58 25 45.5     16.59   15.01 ~ 1 0
22 UCAC4 143-126054 * 13 31 30.9657674145 -61 35 07.068009237     16.57 15.95 15.30 ~ 1 0
23 UCAC4 143-126059 * 13 31 32.1162025232 -61 34 36.142528384     15.87 15.56 14.67 ~ 1 0
24 [EPW2016] V659 Cen 2 * 13 31 32.7415615561 -61 34 42.416013480     18.09   16.50 ~ 1 0
25 V* V659 Cen cC* 13 31 33.4103851030 -61 34 56.514647163 7.57 7.19 6.49     F6/7Ib+B6V 97 0
26 2MASS J13313543-6134477 * 13 31 35.4652588845 -61 34 47.602831615     17.59   16.12 ~ 1 0
27 UCAC4 143-126082 * 13 31 36.7329988833 -61 34 52.773709260     15.73   14.56 ~ 1 0
28 [EPW2016] V737 Cen 2 * 14 37 10.00 -62 00 49.9     17.67   16.06 ~ 1 0
29 [EPW2016] V737 Cen 1 * 14 37 11.00 -62 00 36.1     17.22   15.61 ~ 1 0
30 V* V737 Cen cC* 14 37 11.9678353635 -62 00 39.242308318   7.74 6.77   5.701 G0/1Ib 62 0
31 [EPW2016] S Nor 4 * 16 18 50.10 -57 53 54.9     13.95   13.05 ~ 1 0
32 [EPW2016] S Nor 2 * 16 18 51.50 -57 54 19.4     16.32   15.12 ~ 1 0
33 V* S Nor cC* 16 18 51.8313333962 -57 53 59.253617873 8.15 7.49 6.49   5.427 F8/G0Ib 348 1
34 [EPW2016] S Nor 5 * 16 18 51.90 -57 53 44.6     18.00   16.48 ~ 1 0
35 [EPW2016] S Nor 6 * 16 18 52.00 -57 53 46.2     17.37   15.83 ~ 1 0
36 [EPW2016] S Nor 1 * 16 18 52.20 -57 54 19.3     16.45   15.30 ~ 1 0
37 [EPW2016] S Nor 3 * 16 18 52.60 -57 53 53.5     18.06   16.62 ~ 1 0
38 Gaia DR2 4175017625462646656 * 17 52 38.0510396851 -06 08 52.345961372     17.13   15.13 ~ 1 0
39 V* Y Oph cC* 17 52 38.7021149511 -06 08 36.875163136 8.62 7.61 6.21     G3Ia 347 0
40 Gaia DR2 4096107909354662784 * 18 21 22.6721686073 -18 51 45.716988778     17.06   15.21 ~ 1 0
41 V* Y Sgr cC* 18 21 22.9864295 -18 51 36.001763 7.31 6.69 5.75   4.810 F8II 274 0
42 V* U Sgr cC* 18 31 53.3321808602 -19 07 30.262730218 8.50 7.81 6.68   5.413 G1Ib 439 0
43 [EPW2016] U Sgr 3 * 18 31 53.6706021713 -19 07 46.865864692     17.66   15.72 ~ 1 0
44 UCAC4 355-148280 * 18 31 53.7623298009 -19 07 11.480738193     16.32 15.96 14.80 ~ 1 0
45 [EPW2016] U Sgr 2 * 18 31 54.1226531457 -19 07 38.759747449     17.42   15.47 ~ 1 0
46 V* V473 Lyr cC* 19 15 59.4894683081 +27 55 34.683764506 7.18 6.770 6.153     F8Ib-II 207 0
47 [EPW2016] V473 Lyr 1 * 19 16 00.30 +27 55 45.2     14.89   13.66 ~ 1 0
48 [EPW2016] X Cyg 2 * 20 43 23.50 +35 35 03.9     16.33   14.97 ~ 1 0
49 V* X Cyg cC* 20 43 24.1918662954 +35 35 16.075732392 8.69 7.70 6.47   5.241 F7Ib 444 0
50 [EPW2016] X Cyg 1 * 20 43 24.40 +35 35 28.8     18.61   16.93 ~ 1 0
51 * del Cep cC* 22 29 10.2650184 +58 24 54.713856 4.71 4.35 3.75   3.219 F5Iab:+B7-8 688 0

    Equat.    Gal    SGal    Ecl

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2021.03.03-10:48:03

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