2008A&A...488..685V


Query : 2008A&A...488..685V

2008A&A...488..685V - Astronomy and Astrophysics, volume 488, 685-696 (2008/9-3)

Testing the forward modeling approach in asteroseismology. I. Seismic solutions for the hot B subdwarf Balloon 090100001 with and without a priori mode identification.

VAN GROOTEL V., CHARPINET S., FONTAINE G., BRASSARD P., GREEN E.M., CHAYER P. and RANDALL S.K.

Abstract (from CDS):

Balloon 090100001, the brightest of the known pulsating hot B subdwarfs, exhibits simultaneoulsy both short- and long-period pulsation modes, and shows relatively large amplitudes for its dominant modes. For these reasons, it has been studied extensively over the past few years, including a successful experiment carried out at the Canada-France-Hawaii Telescope to pin down or constrain the value of the degree index l of several pulsation modes through multicolor photometry. The primary goal of this paper is to take advantage of such partial mode identification to test the robustness of our standard approach to the asteroseismology of pulsating subdwarf B stars. The latter is based on the forward approach whereby a model that best matches the observed periods is searched for in parameter space with no a priori assumption about mode identification. When successful, this method leads to the determination of the global structural parameters of the pulsator. As a bonus, it also leads, after the fact, to complete mode identification. For the first time, with the availability of partial mode identification for Balloon 090100001, we are able to evaluate the sensitivity of the inferred seismic model to possible uncertainty in mode identification. We carry out a number of exercises based on the double optimization technique that we developed within the framework of the forward modeling approach in asteroseismology. We use the set of ten periods corresponding to the independent pulsation modes for which values of l have been either formally identified or constrained through multicolor photometry in Balloon 090100001. These exercises differ in that they assume different a priori mode identification. Our primary result is that the asteroseismic solution stands very robust, whether or not external constraints on the values of the degree l are used. Although this may come as a small surprise, the test proves to be conclusive, and small differences in mode identification among the ten modes do not affect in any significant way, at the typical accuracy presently achieved, the final emergent seismic model. This is due to the structure of the p-mode pulsation spectra in sdB stars. In all cases, the inferred structural parameters of Balloon 090100001 remain practically unchanged. They correspond, and this constitutes our second important result, to a star beyond the TAEHB with Teff=28000±1200K, logg=5.383±0.004, M*/M=0.432±0.015, and logMenv/M*=-4.89±0.14. Other structural parameters are also derived.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: interiors - stars: subdwarfs - stars: individual: Balloon 090100001

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 PG 0014+068 HS* 00 16 54.2537878176 +07 04 30.043437816   15.3       sdO 71 1
2 V* DW Lyn HS* 07 07 09.7960158264 +60 38 50.159268348   14.7   15.34   sdB 52 1
3 V* DT Lyn HS* 09 14 55.3780066224 +45 23 41.396157600   14.92       sdBO 27 0
4 V* UY Sex HS* 10 50 02.8265487864 -00 00 36.879009588 12.063 13.184 13.474 13.606 13.769 sdO9VIIHe6 160 0
5 Feige 48 HS* 11 47 14.4978515760 +61 15 31.789400364   13.12 13.28     sdB 115 0
6 PG 1219+534 HS* 12 21 29.0914917288 +53 04 36.796062144   12.41       sdB 82 1
7 PG 1325+102 HS* 13 27 48.5600155368 +09 54 51.049107756   13.73 13.98 14.29   sdBO 56 1
8 CD-40 13747 HS* 20 15 04.7880723672 -40 05 44.110361148 11.91 12.09 11.82     sdO 47 0
9 V* V391 Peg HS* 22 04 12.1045050096 +26 25 07.819080600   14.41 14.61 15.00   sdB 108 2
10 Balloon 90100001 HS* 23 15 21.4810390968 +29 05 01.433373360   11.90 12.30     sdB 88 0

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2023.05.30-06:44:27

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