1997A&A...323..429B


Query : 1997A&A...323..429B

1997A&A...323..429B - Astronomy and Astrophysics, volume 323429-441 (1997/7-2)

A spectroscopic search for high azimuthal-order pulsation in broad-lined late F- and early G-stars.

BAADE D. and KJELDSEN H.

Abstract (from CDS):

During 3 consecutive nights, 13 southern F- and G-type dwarfs and giants outside the conventional δ Scuti instability strip were observed at high spectral (3km/s) and medium temporal (10-15min) resolution. The stars were selected for their reported broad spectral lines (vsini≥40km/s) so that pulsation in higher azimuthal-order nonradial harmonics could, via the rotational Doppler effect, reveal itself by line profile variability. Two stars turned out to have very narrow lines, one was confirmed as a short-period double-lined binary. Line profile ondulations typical of pulsation with azimuthal order 8≤m≤14 were detected in δ Aql and ε2 Ara. In addition, ε2 Ara displayed line profile distortions at a larger scale as they would result from a mode with m∼4. The observational sampling of all three variabilities constrains possible periods only poorly. However, if the variations are periodic, they may well be too slow for p-mode oscillations. This would suggest a relation to the new class of γ Dor variables in which g-modes seem to be excited. If so, the two stars could be the first γ Dor stars with detected higher nonradial-harmonic pulsation. While uvby photometry places δ Aql still just within the δ Scuti strip, ε2 Ara would be the reddest candidate γ Dor star to date. For the remaining 8 stars, upper amplitude limits between 2 and 6km/s were derived for nonradial mode orders 6≤m≤16 and p-modes with periods ∼20minutes. In 3 stars narrow absorption lines were detected which probably are due to a cool companion.

Abstract Copyright: ∼

Journal keyword(s): stars: oscillations - stars: δ Sct - Sun: oscillations - stars: individual: delta Aql, ε2 Ara (HD 153580)

Simbad objects: 13

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Number of rows : 13
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 * psi03 Psc * 01 09 49.2008972448 +19 39 30.264861132   6.263 5.562     F9IIIa 136 0
2 * kap Tuc PM* 01 15 46.0891031031 -68 52 33.401317053   5.39 4.95 4.82   F6V 146 0
3 * b02 Car PM* 08 59 24.1816749896 -59 05 01.362386263   5.58 5.16     F4V 86 0
4 * iot Cha PM* 09 24 09.2243584872 -80 47 12.757529220   5.81 5.36     F3/5III/V 58 0
5 HD 99453 SB* 11 25 43.1445953813 -63 58 20.917354031   5.67 5.17     F7V 66 0
6 * 66 Vir PM* 13 24 33.2485660488 -05 09 50.404470804   6.167 5.749     K2V 87 0
7 * g Lup PM* 15 41 11.3768069149 -44 39 40.341696305   5.036 4.633     F4V 212 0
8 * eps02 Ara ** 17 03 08.7535948608 -53 14 12.969631572   5.750 5.278     F5VFe+0.5 97 0
9 * eta Sco PM* 17 12 09.1940948534 -43 14 21.082311424 3.83 3.74 3.33 2.97 2.77 F5IV 158 0
10 * rho Tel SB* 19 06 19.9561471392 -52 20 27.280858848   5.700 5.174     F6V 85 0
11 * del Aql ** 19 25 29.90139 +03 06 53.2061 3.72 3.68 3.36 3.11 2.95 F1IV-V(n) 247 0
12 HD 189245 PM* 20 00 20.2493681318 -33 42 12.424573369   6.15 5.66     F7V 119 0
13 * alf01 Cap ** 20 17 38.8691281056 -12 30 29.563869708 6.14 5.34 4.27 3.49 2.94 G3Ib 142 0

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