2008A&A...480..215H

Query : 2008A&A...480..215H

2008A&A...480..215H - Astronomy and Astrophysics, volume 480215-222 (2008/3-2)

Precise radial velocities of giant stars. IV. A correlation between surface gravity and radial velocity variation and a statistical investigation of companion properties.

HEKKER S., SNELLEN I.A.G., AERTS C., QUIRRENBACH A., REFFERT S. and MITCHELL D.S.

Abstract (from CDS):

Since 1999, we have been conducting a radial velocity survey of 179 K giants using the Coude Auxiliary Telescope at UCO/Lick observatory. At present ∼20-100 measurements have been collected per star with a precision of 5 to 8m/s. Of the stars monitored, 145 (80%) show radial velocity (RV) variations at a level >20m/s, of which 43 exhibit significant periodicities. Our aim is to investigate possible mechanism(s) that cause these observed RV variations. We intend to test whether these variations are intrinsic in nature, or possibly induced by companions, or both. In addition, we aim to characterise the parameters of these companions. A relation between logg and the amplitude of the RV variations is investigated for all stars in the sample. Furthermore, the hypothesis that all periodic RV variations are caused by companions is investigated by comparing their inferred orbital statistics with the statistics of companions around main sequence F, G, and K dwarfs. A strong relation is found between the amplitude of the RV variations and logg in K giant stars, as suggested earlier by Hatzes & Cochran (1998, ASP Conf. Ser., 154, 311). However, most of the stars exhibiting periodic variations are located above this relation. These RV variations can be split in a periodic component which is not correlated with logg and a random residual part which does correlate with logg. Compared to main-sequence dwarf stars, K giants frequently exhibit periodic RV variations. Interpreting these RV variations as being caused by companions, the orbital parameters are different from the companions orbiting dwarfs. Intrinsic mechanisms play an important role in producing RV variations in K giants stars, as suggested by their dependence on logg. However, it appears that periodic RV variations are additional to these intrinsic variations, consistent with them being caused by companions. If indeed the majority of the periodic RV variations in K giants is interpreted as due to substellar companions, then massive planets are significantly more common around K giants than around F, G, K main-sequence stars.

Abstract Copyright: ∼

Journal keyword(s): stars: variables: general - techniques: radial velocities - line: profiles

Simbad objects: 55

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Number of rows : 55
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 * bet Cet PM* 00 43 35.37090 -17 59 11.7827 3.90 3.02 2.01 1.29 0.78 G9.5IIICH-1 543 1
2 * ups Per PM* 01 37 59.5580239328 +48 37 41.563066970 6.29 4.85 3.57 2.61 1.96 K3-IIICN0.5 244 0
3 * nu. Psc * 01 41 25.8941428289 +05 29 15.401884416 7.36 5.81 4.44 3.38 2.67 K3III 248 0
4 * eta02 Hyi PM* 01 54 56.1314447592 -67 38 50.291415024   5.623 4.685     G8IIIb 129 1
5 HD 13189 * 02 09 40.1723129208 +32 18 59.160568824   9.04 7.55     K1II-III 88 1
6 HD 17092 RG* 02 46 22.1182598088 +49 39 11.095466760   9.00 7.73     K2III 54 1
7 * 24 Per * 02 59 03.6768425424 +35 10 59.271233124 7.460 6.170 4.930     K2III 130 0
8 * sig Per V* 03 30 34.4853660216 +47 59 42.778854240 7.25 5.71 4.36     K3-III 135 0
9 HD 25723 * 04 04 22.7156192304 -12 47 32.268481764   6.688 5.611     K1III 49 0
10 * alf Tau LP? 04 35 55.23907 +16 30 33.4885 4.32 2.40 0.86 -0.37 -1.31 K5+III 1298 2
11 * iot Aur V* 04 56 59.6200224533 +33 09 57.937579478 6.00 4.22 2.69 1.63 0.81 K3II-III 288 0
12 * pi.06 Ori V* 04 58 32.9022894600 +01 42 50.448732336   5.853 4.459     K2-IIb 142 0
13 * nu.02 CMa PM* 06 36 41.0376788353 -19 15 21.169452656 5.96 5.011 3.91 3.13 2.61 K1.5III-IVFe1 282 1
14 HD 47526 * 06 39 54.5261300496 +19 52 19.187893740   9.49 9.44     A 5 0
15 * omi01 CMa s*r 06 54 07.9522701192 -24 11 03.159501504 7.59 5.60 3.87 2.70 1.88 K2Iab 185 0
16 * tet CMa PM* 06 54 11.3988612864 -12 02 19.061163780 7.20 5.51 4.08 2.95 2.17 K3/4III 233 0
17 * tau Gem PM* 07 11 08.3703137689 +30 14 42.589571474 7.08 5.68 4.42 3.45 2.82 K2III 175 1
18 HD 59686 PM* 07 31 48.4045109592 +17 05 09.764723724   6.574 5.442     K2III 130 1
19 BD-13 2130 * 07 37 09.2332503816 -13 54 23.956897032   11.31 10.04     G5IV-V/K2III 78 1
20 * alf CMi SB* 07 39 18.11950 +05 13 29.9552 0.82 0.79 0.37 -0.05 -0.28 F5IV-V+DQZ 1925 0
21 * bet Gem PM* 07 45 18.94987 +28 01 34.3160 3.00 2.14 1.14 0.39 -0.11 K0IIIb 1150 2
22 HD 63752 * 07 50 10.5764471832 -09 11 00.390967872   7.051 5.598     K2III 36 0
23 * 3 Cnc * 08 00 47.3075512008 +17 18 31.321989432   6.904 5.588     K3III 57 0
24 * bet Cnc PM* 08 16 30.9209888482 +09 11 07.958245527 6.750 5.000 3.520 2.42 1.62 K4IIIBa0.5: 383 0
25 * pi.02 UMa PM* 08 40 12.8171670288 +64 19 40.570243212 6.94 5.78 4.61 3.72 3.09 K1+III 185 1
26 * alf Hya * 09 27 35.24270 -08 39 30.9583 5.14 3.42 1.97 0.93 0.16 K3IIIa 455 1
27 * 18 Leo * 09 46 23.3273119968 +11 48 36.155648304   7.142 5.644     K4III 58 0
28 * 46 LMi PM* 10 53 18.6891667765 +34 12 53.611679098 5.79 4.87 3.83 3.00 2.46 K0+III-IV 244 0
29 * 44 UMa PM* 10 53 34.4520785448 +54 35 06.458632728   6.451 5.111     K3III 125 0
30 * chi UMa PM* 11 46 03.0140687528 +47 46 45.855272276 6.06 4.90 3.72 2.84 2.24 K0.5IIIb: 228 0
31 HD 104985 HB* 12 05 15.1171894272 +76 54 20.642733144       5.2   G8.5IIIb 172 1
32 NGC 4349 127 * 12 24 35.4709473000 -61 49 11.861413644   12.85 10.82     ~ 56 1
33 HD 115478 * 13 17 15.6279440976 +13 40 32.706746400 8.130 6.630 5.330     K3III 77 0
34 * alf Boo RG* 14 15 39.67207 +19 10 56.6730 2.46 1.18 -0.05 -1.03 -1.68 K1.5IIIFe-0.5 2417 1
35 * alf Cen A SB* 14 39 36.49400 -60 50 02.3737 0.96 0.72 0.01     G2V 1352 1
36 * ksi02 Lib * 14 56 46.1150412384 -11 24 34.920108828   6.946 5.450     K4III 77 0
37 * 110 Vir PM* 15 02 54.0375635908 +02 05 28.695699730 6.31 5.44 4.40 3.59 3.05 K0+IIIbFe-0.5 133 0
38 HD 135534 * 15 16 23.0106600888 -22 23 57.891494904   6.877 5.506     K2III 41 0
39 * iot Dra V* 15 24 55.7738042889 +58 57 57.837111857 5.68 4.45 3.29 2.51 1.91 K2III 428 1
40 * chi Sco * 16 13 50.9062585128 -11 50 15.892301544   6.615 5.239     K3III 83 0
41 * eps Oph PM* 16 18 19.2902245358 -04 41 33.047349888 4.95 4.21 3.23 2.54 2.05 G9.5IIIbFe-0.5 246 0
42 HD 148513 PM* 16 28 33.9807973104 +00 39 54.001143144 8.65 6.85 5.39     K3V 170 0
43 * e Oph PM* 17 18 36.9902276784 +10 51 52.111241856   6.550 5.020     K4II-III 78 0
44 HD 157617 * 17 23 57.6158315040 +08 51 09.252688284   6.999 5.763     K1III 39 0
45 * sig Oph V* 17 26 30.8807335272 +04 08 25.293765444 7.39 5.82 4.31 3.22 2.46 K2II 183 0
46 * lam Her V* 17 30 44.3098209648 +26 06 38.324204244 7.53 5.85 4.41 3.37 2.62 K3.5III 139 0
47 * tet Her V* 17 56 15.1809747319 +37 15 01.932000161 6.70 5.23 3.88 2.98 2.38 K1IIaCN2 226 0
48 * nu. Oph PM* 17 59 01.5922136612 -09 46 25.080976810 5.20 4.33 3.34 2.64 2.16 G9IIIa 226 1
49 * alf Sct PM* 18 35 12.4271571798 -08 14 38.653839451 6.70 5.17 3.83 2.86 2.18 K3III 189 0
50 HD 209761 * 22 05 11.3344094040 +26 40 25.285361988   7.016 5.744     K3III 44 0
51 * zet Cep s*r 22 10 51.2777055617 +58 12 04.542602641 6.62 4.90 3.35 2.27 1.49 K1.5Ib 295 0
52 HD 210762 * 22 12 08.0937068712 +24 57 02.313215568   7.432 5.923     K0 34 0
53 HD 211073 ** 22 13 52.7275081368 +39 42 53.728839720 7.32 5.88 4.49 3.48 2.74 K2.5III 118 0
54 HD 217303 PM* 23 00 05.7892478064 -25 09 51.047833032   6.904 5.656     K0IICNIII 27 0
55 * psi01 Aqr PM* 23 15 53.4940495770 -09 05 15.844964053 6.37 5.36 4.25 3.46 2.90 K1-IIIFe-0.5 260 1

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