2010AJ....139.1968E

Query : 2010AJ....139.1968E

2010AJ....139.1968E - Astron. J., 139, 1968-1974 (2010/May-0)

Chandra observation of Polaris: census of low-mass companions.

EVANS N.R., GUINAN E., ENGLE S., WOLK S.J., SCHLEGEL E., MASON B.D., KAROVSKA M. and SPITZBART B.

Abstract (from CDS):

We have observed Cepheid Polaris (α UMi A: F7 Ib [Aa] + F6 V [Ab]) with Chandra ACIS-I for 10 ks. An X-ray source was found at the location of Polaris with log LX= 28.89 erg/s (0.3-8 keV) and kT = 0.6 keV. A spectrum this soft could come from either the supergiant or the dwarf, as shown by comparable coronal stars. Two resolved low-mass visual companions, "C" and "D," are not physical members of the system based on the lack of X-rays (indicating an age older than the Cepheid) and inconsistent proper motions. Polaris B is not an X-ray source, consistent with its early F spectral type, and probably does not have a lower mass companion itself. A possible more distant member is identified, and an additional less plausible one. This provides a complete census of companions out to 0.1 pc covering a mass ratio range of an order of magnitude and a ΔV of nearly 15 mag.

Abstract Copyright: ∼

Journal keyword(s): binaries: general - stars: variables: Cepheids - X-rays: 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 - 2026 		#notes
1 UCAC3 359-198 * 02 10 05.9552034480 +89 16 26.410445796           M4 1 0
2 UCAC3 359-211 * 02 14 55.8625249536 +89 08 51.842619636           K5-7 3 0
3 * alf UMi B V* 02 30 36.0860424600 +89 15 39.203145900   8.69 8.20     F3V 39 0
4 UCAC3 359-247 * 02 30 44.3425192632 +89 14 29.699267100       14.07   ~ 10 0
5 * alf UMi cC* 02 31 49.09456 +89 15 50.7923 3.00 2.62 2.02 1.53 1.22 F8Ib 716 2
6 UCAC3 359-258 * 02 35 12.0618732552 +89 15 45.147046968       14.34   ~ 9 0
7 * alf Per V* 03 24 19.3700924 +49 51 40.245455 2.64 2.27 1.79     F5Ib 870 1
8 Cl Melotte 20 MGr 03 26 50.6 +48 51 48           ~ 928 0
9 Cl Melotte 22 OpC 03 46 38.0 +24 10 41           ~ 3679 0
10 NAME Tau-Aur Complex SFR 04 30 +25.0           ~ 1453 0
11 * bet Cam * 05 03 25.0910670105 +60 26 32.083933247 5.57 4.95 4.02 3.33 2.86 G1Ib 190 0
12 * bet Dor cC* 05 33 37.5159729864 -62 29 23.376457680 5.13 4.58 3.76 3.55 3.12 F8/G0Ib 401 0
13 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2514 0
14 M 42 HII 05 35 16.8 -05 23 15           ~ 4411 0
15 * alf Car * 06 23 57.10988 -52 41 44.3810 -0.49 -0.59 -0.74 -0.96 -1.13 A9II 461 1
16 * alf CMa SB* 06 45 08.91728 -16 42 58.0171 -1.51 -1.46 -1.46 -1.46 -1.43 A0mA1Va 1610 0
17 * alf CMa B WD* 06 45 09.3041925037 -16 43 00.724740067   8.41 8.44     DA1.9 563 1
18 * zet Gem cC* 07 04 06.5312384690 +20 34 13.074474962 5.20 4.58 3.79   3.082 G1Ib 596 0
19 * l Car cC* 09 45 14.8117044917 -62 30 28.450312664   5.09 3.75     G5Iab/b 343 0
20 NAME Cha 1 MoC 11 06 48 -77 18.0           ~ 1266 1
21 NAME Upper Sco Association As* 16 12 -23.4           ~ 1586 1
22 * bet Dra * 17 30 25.9616959 +52 18 04.999351 4.43 3.79 2.81 2.12 1.64 G2Ib-IIa 428 0
23 * eta Aql cC* 19 52 28.3689223781 +01 00 20.371980515 5.12 4.61 3.80   3.030 F6Iab+B9.8V 701 0
24 * bet Aqr * 21 31 33.5320760349 -05 34 16.229381029 4.27 3.71 2.89 2.29 1.84 G0Ib 463 0
25 * alf Aqr * 22 05 47.0355458275 -00 19 11.463439527 4.65 3.90 2.94 2.27 1.76 G2Ib 451 0
26 * del Cep cC* 22 29 10.2626640314 +58 24 54.697613650 4.71 4.35 3.75   3.219 F5Iab:+B7-8 763 0
27 V* Z Lac cC* 22 40 52.1457028632 +56 49 46.083774432   9.71 8.57   7.164 F6Ib 245 0

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