2001ApJ...563..325D


C.D.S. - SIMBAD4 rel 1.7 - 2020.05.25CEST01:45:46

2001ApJ...563..325D - Astrophys. J., 563, 325-333 (2001/December-2)

Chemical abundances of OB stars with high projected rotational velocities.

DAFLON S., CUNHA K., BUTLER K. and SMITH V.V.

Abstract (from CDS):

Elemental abundances of carbon, nitrogen, oxygen, magnesium, aluminum, and silicon are presented for a sample of 12 rapidly rotating OB star (vsini>60km.s–1) members of the Cep OB2, Cyg OB3, and Cyg OB7 associations. The abundances are derived from spectrum synthesis, using both LTE and non-LTE calculations. As found in almost all previous studies of OB stars, the average abundances are slightly below solar, by about 0.1 to 0.3 dex. In the case of oxygen, even with the recently derived low solar abundances, the OB stars are closer to, but still below, the solar value.
Result. for the nine Cep OB2 members in this sample can be combined with results published previously for eight Cep OB2 stars with low projected rotational velocities to yield the most complete set of abundances, to date, for this particular association. These abundances provide a clear picture of both the general chemical and individual stellar evolution that has occurred within this association. By placing the Cep OB2 stars studied in an HR-diagram we identify the presence of two distinct age subgroups, with both subgroups having quite uniform chemical abundances. Two stars are found in the older subgroup that show significant N/O overabundances, with both stars being two of the most massive, the most evolved, and the most rapidly rotating of the members studied in Cep OB2. These characteristics of increased N abundances being tied to high mass, rapid rotation, and an evolved phase are those predicted from models of rotating stars that undergo rotationally driven mixing.

Abstract Copyright:

Journal keyword(s): Stars: Abundances - Stars: Early-Type - Stars: Rotation

Status at CDS:  

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 - 2020
#notes
1 V* V453 Cyg Al* 20 06 34.9662773363 +35 44 26.267177168 7.83 8.52 8.40     B1III 180 0
2 Ass Cyg OB 3 As* 20 07 +35.9           ~ 165 0
3 HD 228199 * 20 11 27.2644566068 +36 29 56.854384259   9.41 9.34     B0.5:V 31 0
4 Ass Cyg OB 7 As* 21 08 +47.6           ~ 193 0
5 HD 202347 * 21 13 41.8579262350 +45 36 41.260356208 6.6 7.41 7.50     B1V 61 0
6 HD 239681 * 21 28 26.7493230578 +60 14 55.567143958 9.01 9.55 9.34     B5 14 0
7 HD 205794 * 21 35 43.8313293451 +57 28 03.477814338 8.22 8.71 8.43     B0.5V 43 0
8 HD 239710 Y*O 21 36 41.0387098938 +57 30 08.251421528 9.43 9.86 12.74     B3V 30 1
9 HD 205948 * 21 36 47.8727267523 +57 35 02.093115652 8.33 8.90 8.65     B2V 34 0
10 HD 206183 * 21 38 26.2840282278 +56 58 25.455651545 6.75 7.55 7.41     O9.5IV-V 86 0
11 HD 239724 * 21 38 39.5276966902 +57 22 01.708417892 9.02 9.51 9.14     B1III 30 0
12 LS III +57 12 ** 21 38 56.733 +57 29 39.22 7.53     8.73   B1V 38 0
13 HD 206267 SB* 21 38 57.6182747705 +57 29 20.557311013 5.09 5.83 5.62   5.56 O6.0V((f))+O9:V 450 0
14 IC 1396 OpC 21 39 00 +57 29.4           ~ 444 1
15 HD 206327 * 21 39 01.0395954253 +61 33 22.131900075 8.31 9.37 9.19     B2V 40 0
16 HD 239729 ** 21 39 27.4061267024 +57 29 00.804868050 8.17 8.71 8.35   7.96 B0V 62 1
17 HD 239743 ** 21 42 46.6297601332 +60 17 45.301641792 9.45 9.53 9.03     B2V 25 0
18 HD 239742 * 21 42 52.1028735885 +57 01 01.025430421 9.05 9.61 9.41     B2V 30 0
19 HD 239745 Em* 21 43 24.4644726136 +57 01 23.352412705 8.60 9.21 8.92     B1V 34 0
20 HD 239748 * 21 43 41.3010635844 +58 14 23.293287780 8.26 8.92 8.75     B1V 27 0
21 HD 235618 * 21 46 50.8196024301 +55 20 07.194099369 10.03 10.28 9.77     B1 22 0
22 HD 207538 * 21 47 39.7898466603 +59 42 01.344202478 7 7.55 7.30     O9.7IV 177 1
23 HD 207951 * 21 50 40.6341866736 +61 48 11.226432058 7.75 8.30 8.18     B2V 26 0
24 Ass Cep OB 2 As* 21 51 +60.0           ~ 279 0
25 HD 209339 ** 22 00 39.2641276076 +62 29 16.064937019 5.9 8.73 8.51 7.61   O9.7IV 168 0
26 Ass Cep OB 2b As* ~ ~           ~ 4 0
27 Ass Cep OB 2a As* ~ ~           ~ 6 0

    Equat.    Gal    SGal    Ecl

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2020.05.25-01:45:46

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