2007ApJ...658.1203J


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.30CET22:49:15

2007ApJ...658.1203J - Astrophys. J., 658, 1203-1216 (2007/April-1)

A search for nitrogen-enhanced metal-poor stars.

JOHNSON J.A., HERWIG F., BEERS T.C. and CHRISTLIEB N.

Abstract (from CDS):

Theoretical models of very metal-poor intermediate-mass asymptotic giant branch (AGB) stars predict a large overabundance of primary nitrogen. The very metal-poor, carbon-enhanced, s-process-rich stars, which are thought to be the polluted companions of now extinct AGB stars, provide direct tests of the predictions of these models. Recent studies of the carbon and nitrogen abundances in metal-poor stars have focused on the most carbon-rich stars, leading to a potential selection bias against stars that have been polluted by AGB stars that produced large amounts of nitrogen and hence have small [C/N] ratios. We call these stars nitrogen-enhanced metal-poor (NEMP) stars and define them as having [N/Fe]>+0.5 and [C/N]←0.5. In this paper we report on the [C/N] abundances of a sample of 21 carbon-enhanced stars, all but three of which have [C/Fe]<+2.0. If NEMP stars were made as easily as carbon-enhanced metal-poor (CEMP) stars, then we expected to find between two and seven NEMP stars. Instead, we found no NEMP stars in our sample. Therefore, this observational bias is not an important contributor to the apparent dearth of N-rich stars. Our [C/N] values are in the same range as values reported previously in the literature (-0.5 to +2.0), and all stars are in disagreement with the predicted [C/N] ratios for both low- and high-mass AGB stars. We suggest that the decrease in [C/N] from the low-mass AGB models is due to enhanced extramixing, while the lack of NEMP stars may be caused by unfavorable mass ratios in binaries or the difficulty of mass transfer in binary systems with large mass ratios.

Abstract Copyright:

Journal keyword(s): Nuclear Reactions, Nucleosynthesis, Abundances - Stars: Abundances - Stars: AGB and Post-AGB - Stars: Carbon - Stars: Population II

VizieR on-line data: <Available at CDS (J/ApJ/658/1203): table2.dat table10.dat>

Simbad objects: 69

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Number of rows : 69

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 HE 0012-1441 Pe* 00 15 27.0563104549 -14 24 37.625530758     16.40     CEMP-s 13 0
2 HE 0024-2523 Pe* 00 27 27.6485410349 -25 06 28.291081599 15.067 15.32 14.91     CEMP-s 65 0
3 BPS CS 31062-0050 Pe* 00 30 31.0633474070 -12 05 10.873150611   13.7 13.05 12.681 12.309 CEMP-r/s 60 0
4 BPS CS 31062-0041 Pe* 00 35 03.0120523198 -15 54 29.359977750   14.754 13.934 13.476 12.984 ~ 12 0
5 GD 632 PM* 00 38 26.2800485829 -19 26 34.649458967   15.38 14.83 14.86 14.201 ~ 7 0
6 CD-24 266 BS* 00 40 47.9313778053 -24 07 34.183052519   12.955 12.656 12.441 12.216 CEMP-s 90 0
7 SKB 2 Pe* 00 41 39.8197261334 -26 18 54.463949137   13.338 12.221 11.704 11.321 CEMP-s 83 0
8 SB 960 Pe* 00 44 03.5698517387 -13 55 26.270588506   12.69 12.15 11.806 11.483 CEMP-s 103 0
9 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9607 1
10 CD-26 304 Pe* 00 57 18.1376089543 -25 26 09.699477820   13.57 12.69 12.198 11.759 CEMP-s 62 1
11 HE 0058-0244 Pe* 01 00 53.0236506123 -02 28 19.948243997   14.42 13.73 13.331 12.942 CEMP-r/s 34 0
12 BPS CS 22183-0031 Pe* 01 09 05.0899437519 -04 43 21.344131594   14.24 13.62 13.178 12.724 ~ 39 0
13 HE 0107-5240 Pe* 01 09 29.1554552993 -52 24 34.203535506   15.89 15.07 15.10 14.283 CEMP-no 229 0
14 TYC 5273-836-1 Pe* 01 14 06.4775569690 -11 02 35.436341244   12.32 12.43 11.961 11.509 ~ 11 0
15 HE 0143-0441 Pe* 01 45 37.9166316774 -04 26 43.245126791     16.38     CEMP-s 26 0
16 BPS CS 22958-0042 Pe* 02 01 07.4296353198 -57 16 58.851945318   14.037 14.52 14.222 13.902 CEMP-no 35 0
17 HE 0212-0557 Pe* 02 15 02.5101220196 -05 43 23.652630023     14.70     CEMP-s 15 0
18 BPS CS 22958-0083 Pe* 02 15 42.7298911215 -53 59 56.258017880 15.057 15.09 14.44 13.981 13.521 CEMP-no 20 0
19 HE 0305-5442 Pe* 03 06 29.5014936276 -54 30 32.498352902   14.44 13.70 13.212 12.715 KIIvw 73 0
20 BPS CS 29526-0110 Pe* 03 27 43.6395462631 -23 00 29.931204041   13.71 13.35 13.116 12.834 CEMP-r/s 47 0
21 HE 0336+0113 Pe* 03 38 52.9028202374 +01 23 07.778935029     14.96     CEMP-s 19 0
22 BPS CS 29529-0041 * 03 55 08.3656865389 -59 48 06.867711442   12.49 12.47 12.69   A1 4 0
23 HD 25329 PM* 04 03 14.9983565018 +35 16 23.806254921 9.75 9.37 8.50 7.75 7.23 K1VbFe-2 348 0
24 2MASS J04442200-4513542 C* 04 44 22.0060297382 -45 13 54.233994954 13.219 13.51 12.989 12.672 12.372 CEMP-s 22 0
25 HD 74000 PM* 08 40 50.8038415228 -16 20 42.513275817 9.84 10.09 9.66     F2 246 0
26 HE 1031-0020 Pe* 10 34 24.2082433332 -00 36 08.377734105     14.30     CEMP-s 22 0
27 HD 97916 SB* 11 15 54.2294079228 +02 05 11.982106821 9.50 9.61   8.9   F0V 154 0
28 HE 1150-0428 Pe* 11 53 06.6089448606 -04 45 03.484251112     14.91     CEMP-no 27 0
29 BPS CS 22877-0001 Pe* 13 13 55.3726645896 -12 11 41.664182839   12.78 12.38 11.695 11.218 CEMP-no 35 0
30 HE 1327-2326 Pe* 13 30 05.9395582011 -23 41 49.699027289 13.761 14.01 13.55 13.50 12.803 CEMP-no 219 0
31 HD 122653 * 14 02 50.3188208822 +17 59 16.229439851 7.448 9.55 8.06 5.616   K0 13 0
32 HE 1410+0213 Pe* 14 13 06.5623968167 +01 59 21.912907907   14.29 13.25 12.734 12.297 CEMP-no 22 0
33 HE 1434-1442 Pe* 14 37 26.5892140416 -14 54 59.397681972     15.40   15.395 CEMP-s 15 0
34 BPS CS 30301-0015 Pe* 15 08 56.8433023195 +02 30 18.628172611   14.04 13.04   12.063 CEMP-s 44 0
35 HE 1509-0806 Pe* 15 11 41.5759272135 -08 17 40.210829904     14.80     CEMP-s 13 0
36 BPS CS 22884-0097 * 15 47 22.9110883342 -11 07 03.529448265   15.46 14.86 14.461 14.019 ~ 9 0
37 LP 625-44 Pe* 16 43 14.0364804654 -01 55 30.408914037   12.84 11.68     CEMP-s 101 0
38 HD 160617 PM* 17 42 49.3235999900 -40 19 15.505712142   9.18 8.73 8.394 8.065 G0 184 0
39 HD 166913 PM* 18 16 25.6833261555 -59 24 11.241154880   8.66 8.23     F5/7Vw 122 0
40 BPS CS 22947-0187 HB* 19 18 31.6263239095 -47 13 31.155732437   13.63 12.99 12.508 12.085 CEMP-s 35 0
41 BPS CS 22891-0171 Pe* 19 28 04.0286056429 -59 24 26.474409843   15.15 14.29 13.808 13.375 CEMP-s 13 0
42 HD 186478 Pe* 19 45 14.1410795461 -17 29 27.071420634   10.116 9.302 8.527 7.961 K2III 131 0
43 BD-18 5550 Pe* 19 58 49.7370363913 -18 12 11.142309703 10.18 10.03 9.35 9.04 8.74 CEMP-no 164 0
44 BPS CS 22950-0048 HS* 20 20 27.7100566786 -13 08 37.518394718     14.9     sdOHe 3 0
45 BPS CS 22950-0046 Pe* 20 21 28.3976234633 -13 16 33.602336953   15.13 14.224 13.639 13.066 CEMP-no 37 0
46 BPS CS 22879-0029 Pe* 20 38 51.8045564280 -38 36 46.780565144   14.89 14.45 14.145 13.821 CEMP-s 16 0
47 HD 196944 Pe* 20 40 46.0790261041 -06 47 50.650812411   9.01 8.40 8.08   CEMP-s 88 0
48 BPS CS 22880-0074 Pe* 20 46 03.2162078511 -20 59 14.111093923   13.84 13.27 12.770 12.382 CEMP-s 45 0
49 BPS CS 30314-0067 Pe* 20 52 50.9876997217 -34 19 40.549001966   12.98 11.85 11.175 10.583 CEMP-no 27 0
50 BPS CS 29498-0043 Pe* 21 03 52.1197489072 -29 42 50.344264361   14.8 13.72 13.013 12.406 CEMP-no 88 0
51 BPS CS 22898-0027 Pe* 21 05 45.0995574992 -18 36 57.505496795   13.26 12.76 12.476 12.094 CEMP-r/s 80 0
52 BPS CS 22898-0062 * 21 14 10.3425358512 -18 42 43.000233510   14.43 13.80 13.368 12.948 ~ 9 0
53 BPS CS 30322-0023 * 21 30 32.1818570433 -46 16 24.615679322   13.473 12.166 11.498 10.908 ~ 47 0
54 HE 2134-3940 Pe* 21 37 45.7673672486 -39 27 22.314122762   13.790 12.660 12.160 11.760 KIIvw 81 0
55 BPS CS 29495-0042 Pe* 21 39 11.4050814416 -28 17 54.386094187   14.32 13.68 13.192 12.782 CEMP-s 13 0
56 BPS CS 22948-0104 Pe* 21 51 45.7604474454 -37 52 30.874822283   14.55 13.96 13.519 13.108 ~ 13 0
57 HE 2156-3130 Pe* 21 59 05.7785371282 -31 16 12.134699144   14.86 14.07 13.523 13.011 CEMP-no 19 0
58 HE 2158-0348 Pe* 22 00 39.9763616015 -03 34 12.069272984     15.71   14.726 CEMP-s 21 0
59 BPS CS 22881-0036 Pe* 22 07 58.4409012147 -40 44 16.477797121   14.42 13.95 13.633 13.278 CEMP-s 35 0
60 BPS CS 22960-0053 Pe* 22 16 17.0866862947 -43 54 19.740558500 15.69 15.705 14.950 14.537 14.046 CEMP-s 22 0
61 BPS CS 22892-0052 Pe* 22 17 01.6558480594 -16 39 27.051900047   14.03 13.20 13.06 12.19 KIIvw 416 0
62 BPS CS 29502-0092 Pe* 22 22 35.9981441327 -01 38 27.624102360   12.64 11.87 11.365 10.862 CEMP-no 45 0
63 BPS CS 29512-0073 Pe* 22 28 36.7001192788 -12 24 44.112909323   14.71 14.14 13.76 13.384 CEMP-s 18 0
64 HE 2232-0603 Pe* 22 34 47.4283794688 -05 48 17.344893935   16.861 16.51 15.894 15.591 ~ 16 0
65 BPS CS 22887-0048 Pe* 22 46 44.6213635273 -11 08 42.417225666   13.26 12.87 12.588 12.31 CEMP-r/s 20 0
66 BPS CS 22949-0008 Pe* 23 16 58.7311560608 -03 20 52.619469600   14.61 14.15 13.858 13.545 CEMP-s 19 0
67 HE 2323-0256 Pe* 23 26 29.8073543039 -02 39 58.037206596   15.12 14.36   13.358 CEMP-no 172 0
68 BPS CS 22945-0024 Pe* 23 36 42.4769851926 -65 35 43.820932544 15.076 15.08 14.36     CEMP-s 12 0
69 HE 2356-0410 Pe* 23 59 13.1417869434 -03 53 48.220053208   14.39 13.60 13.164 12.713 CEMP-no 82 0

    Equat.    Gal    SGal    Ecl

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2020.11.30-22:49:16

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