2008A&A...483..801A


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.08CEST14:30:21

2008A&A...483..801A - Astronomy and Astrophysics, volume 483, 801-813 (2008/6-1)

The stellar population of the Rosat North Ecliptic Pole survey. II. Spectral analysis.

AFFER L., MICELA G. and MOREL T.

Abstract (from CDS):

X-ray surveys allow to identify young, main-sequence stars in the solar neighborhood. Young, stellar samples, selected according to their activity, can be used to determine the stellar birthrate in the last billion years. The ROSAT North Ecliptic Pole survey (NEP), with its moderately deep sensitivity (fluxes ≃10–14erg/cm2/s), is the best survey, to date, able to sample the intermediate-age (108-109years) nearby population. The identification process of NEP X-ray sources resulted in 144 X-ray sources having a normal stellar counterpart, with an excess of yellow stars with respect to model predictions. We want to determine if these X-ray active stars are young or intermediate-age stars, or active binaries. We acquired high-resolution, high signal-to-noise ratio optical spectra, to determine the age and physical properties of the NEP X-ray-detected stellar sources. We measure the (i) lithium abundance using the LiI 6707.8Å line, which is an excellent, youth indicator for our age range of interest; (ii) rotational and radial velocities (through cross-correlation methods); and (iii) chromospheric emission (from Hα and NaI D1 and D2 lines). The radial velocities distribution is consistent with that of a young field star population of age 4x109yrs, or younger. Rotational velocity measurements imply that our sample is dominated by relatively young or intermediate-age stars, as confirmed by our lithium measurements. Most of the detected stars probably belong to a young or intermediate-age population. Our measurements suggest that a burst in the stellar birthrate of a factor of four occurred in the last 108-years. We cannot, however, exclude the possibility that a small fraction of sources, amongst the fastest of the K-rotators, are old binary systems with tidally-locked rotation.

Abstract Copyright:

Journal keyword(s): stars: rotation - stars: abundances - techniques: spectroscopic - techniques: radial velocities - Galaxy: solar neighbourhood

Status at CDS:  

Simbad objects: 61

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Number of rows : 61

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 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 2949 0
2 Cl Melotte 25 OpC 04 26 54.00 +15 52 00.0           ~ 2629 0
3 TYC 4206-459-1 * 17 19 28.6940151730 +65 22 29.812151954   12.17 11.39 11.27   K0 4 0
4 BD+62 1542 PM* 17 20 05.5423 +62 06 23.656   9.93 9.25     F8 8 0
5 TYC 4210-457-1 PM* 17 20 26.4807663882 +67 03 40.404341605   10.71 10.01     G8 2 0
6 HD 158063 * 17 21 10.4376418810 +69 48 02.546957035   7.99 7.38     F8 20 0
7 TYC 4202-210-1 * 17 21 42.6094501358 +62 00 32.865386229   12.21 11.57     K4 3 0
8 TYC 4421-511-1 * 17 24 00.4992674334 +69 40 29.866527687   12.49 12.49     G2IV 5 0
9 RX J1724.4+6412 EB* 17 24 26.9687436248 +64 12 23.913543451   11.02 10.47     G2 7 0
10 TYC 4206-1161-1 * 17 24 38.9762256406 +64 40 52.434424159   10.78 10.08     G7 5 0
11 TYC 4421-553-1 * 17 26 45.4398267635 +69 37 49.783126727   11.25 10.72     G2 3 0
12 HD 159539 * 17 29 39.4658823695 +68 47 39.604830474   9.58 9.14     G 4 0
13 TYC 4421-47-1 * 17 30 19.8868599537 +69 55 25.955599465   10.43 10.00     G0~ 5 0
14 HD 160198 PM* 17 33 18.0695502799 +67 12 13.387730065   8.08 7.65     F2 21 0
15 RX J1736.2+6502 Ro* 17 36 14.5684031325 +65 02 28.756059446   11.79 10.75     K0 9 0
16 BD+68 946 PM* 17 36 25.8991699744 +68 20 20.904135942 11.73 10.65   8.3   M3.0V 249 0
17 BD+70 947 * 17 39 15.8078408753 +70 20 06.509267204   9.66 9.11     F8 4 0
18 V* MS Dra BY* 17 39 55.6943269044 +65 00 05.890269248   9.33 8.40     K0V 36 0
19 HD 161919 * 17 42 26.4399171876 +69 07 59.917929852   9.01 8.56     G0 4 0
20 BD+66 1042 * 17 43 01.8678096132 +66 06 42.727775187   10.30 9.66     F8V 4 0
21 TYC 4432-885-1 * 17 43 51.9916132813 +70 31 40.531864772   10.88 10.35     F3 2 0
22 RX J1744.0+7015 EB* 17 44 00.3339735683 +70 15 31.817870343   11.38 10.82     K0 5 0
23 HD 162898 PM* 17 49 03.8676880956 +62 47 55.777844752 7.030 7.060 6.690     F2 21 0
24 V* ET Dra Ro* 17 50 25.1159572611 +70 45 36.441081427   10.71 9.67     K2.5 39 1
25 BD+67 1039B * 17 52 43.9794030385 +67 00 29.555596256   10.89 10.48     F5VmA7 4 0
26 HD 163788 * 17 52 56.0360921201 +66 25 08.666724172   8.60 7.67     K0 10 0
27 HD 164781 PM* 17 57 03.6426510384 +68 49 19.654243097   9.74 9.01     G8V 6 0
28 BD+64 1235 * 17 58 01.4842653031 +64 09 34.509614760   11.07 10.11     G 4 0
29 TYC 4212-61-1 * 17 58 28.3025700245 +67 26 08.762013795   11.19 10.53     G2 3 0
30 HD 164873 * 17 58 47.7269175937 +63 50 37.804555339   8.66 8.49     A2 4 0
31 HD 164984 * 17 59 13.7347530267 +64 08 33.277562400   7.68 7.26     F2 18 0
32 TYC 4212-1074-1 * 17 59 23.0182425856 +66 02 56.293347352   11.46 10.29     K0III 12 0
33 NAME NEP reg 18 00 00.000 +66 33 38.55           ~ 251 0
34 TYC 4213-617-1 * 18 00 02.1413674424 +66 45 54.996131553   11.28 10.68     F8 6 0
35 V* EF Dra EB* 18 05 30.406392 +69 45 15.54228   10.92 10.34 10.40   F8/9V 73 0
36 HD 166227 * 18 05 30.6059859056 +62 19 00.581456809   9.05 8.15     K0 4 0
37 BD+65 1242 * 18 05 45.4320156434 +65 51 58.912773286   9.79 9.36     F5 4 0
38 HD 166578 * 18 06 40.5629620238 +64 13 17.130010958   7.63 6.68     K0 15 0
39 HD 166975 * 18 08 45.4794599499 +62 56 35.651687711   9.36 8.61     G5 3 0
40 V* LP Dra RS* 18 09 55.4988492938 +69 40 49.790702828       8.0   K2V 41 0
41 TYC 4433-597-1 * 18 10 49.9870904837 +70 16 09.988111008   11.30 10.62     G9 4 0
42 TYC 4429-90-1 * 18 13 48.6193412152 +68 31 32.973194679   12.01 10.76     K2 1 0
43 * 36 Dra PM* 18 13 53.8327884671 +64 23 50.225272101   5.41   4.8   F5V 179 0
44 BD+65 1255 * 18 16 21.3677343573 +65 29 38.077948726   9.92 8.33     K5 2 0
45 TYC 4209-270-1 PM* 18 16 49.7268593974 +65 04 27.499464575   11.57 10.86     ~ 2 0
46 BD+70 990 * 18 18 31.8924450821 +70 42 16.878050731   10.86 10.04     G5 6 0
47 HD 169531 * 18 20 19.2938507500 +65 19 18.805838637   8.46 8.00     F8 15 0
48 TYC 4222-1770-1 PM* 18 21 47.0035251472 +63 57 14.584673663   10.52 9.75     K0 3 0
49 HD 170527 PM* 18 25 10.1138992273 +64 50 18.306252451   7.86 6.86     K0 30 0
50 RX J1825.5+6234 Ro* 18 25 33.0066680565 +62 34 14.703522023   11.52 10.37     K 6 0
51 HD 172066 PM* 18 32 30.2114230407 +68 36 51.096972851   8.11 7.59     G5 20 0
52 LSPM J1833+6513 PM* 18 33 48.068 +65 13 40.23       8.9   K3 4 0
53 TYC 4434-2172-1 * 18 34 33.9660684113 +69 31 45.445990491   12.04 11.24     K5 1 0
54 HD 172569 PM* 18 36 13.2699273811 +65 29 19.297152128 6.440 6.340 6.060     F0V 44 0
55 HD 172669 PM* 18 36 23.4524176434 +66 54 47.672941831   8.18 7.60     G3V 19 0
56 PM J18394+6903 PM* 18 39 25.6971338480 +69 03 03.570036549   12.1   11.522   M2.0V 12 0
57 BD+70 1017 PM* 18 40 43.2195567244 +70 38 49.634316739   10.30 9.41     K2~ 4 0
58 HD 173398 PM* 18 40 56.4083143355 +62 44 58.065638016   7.086 6.091     K0III 34 0
59 BD+69 1000 * 18 43 12.4678973330 +69 55 55.468093628   9.85 9.43     F0 2 0
60 NAME Gould Belt PoG ~ ~           ~ 703 1
61 NAME NEP Supercluster SCG ~ ~           ~ 10 0

    Equat.    Gal    SGal    Ecl

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2020.04.08-14:30:21

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