Towards asteroseismology of main-sequence g-mode pulsators:
Spectroscopic multi-site campaigns for slowly pulsating B stars and Doradus stars
P. De Cat 1, D.J. Wright 1, E. Kambe 2, K.R. Pollard 3, F. Maisonneuve 3, P. Kilmartin 3, H. Lehmann 4, S. Yang 5, S. Saesen 6, F. Carrier 6, D.
Mkrtichian 7, L. Mantegazza 8, M. Rainer 8, E. Poretti 8, D. Laney 9, J.N. Fu 10
Koninklijke Sterrenwacht van België, Ringlaan 3, B-1180 Brussel, Belgium
2Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232, Japan
3 Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
4Thüringer Landessternwarte, Tautenburg, 07778 Tautenburg, Germany
5
Department of Physics and Astronomy, Universtity of Victoria, Victoria, BC V8W 3P6, Canada
6Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
7
Astronomical Observatory of Odessa National University, Marazlievskaya, 1v, 65014 Odessa, Ukraine
8INAF-Brera Astronomical Observatory, Via E. Bianchi 46, 23807 Merate, Italy
9South African Astronomical Observatory, PO Box 9, Observatory, 7935 Cape Town, South Africa
10Department of Astronomy, Beijing Normal University, 19 Avenue Xinjiekouwai, Beijing 100875, China
1

1. INTRODUCTION
In 2007, we started a project, dedicated to main-sequence g-mode pulsators to improve the mode identification techniques for g-mode pulsators and to study the relation between rotation and pulsation froman observational point of view. We therefore selected a sample of slowly pulsating B stars (SPB) and γ Doradus (γDor) stars with a large spread in projected rotational velocity as targets for dedicatedspectroscopic multi-site campaigns (see Table 1). For these targets, photometric observations show multiperiodic variations and/or clear line profile variations (LPVs) have been observed, making themsome of the best candidates available for total characterisation of the pulsation modes. With these multi-site campaigns, we aim to provide both a reliable identification of the strongest modes (degree l andazimuthal number m) and severe restrictions on stellar parameters (including the effective temperature, surface gravity, metallicity, inclination and rotation speed), allowing asteroseismic modelling tobecome possible for these types of stars. Currently, 11 observatories, including Okayama Astrophysical Observatory, which all have excellent high-resolution spectroscopic facilities, are involved in ourobservational efforts (see Table 2). In this poster, we introduce the sample of selected objects and give an overview of the multi-site campaigns that have been organised up to now.
Table 2. Overview of the high-resolution spectrographs involved in our multi-site campaigns so far. For
each spectrograph, we give a reference of the form 'instrument@observatory/telescope' used in the text, theresolution (R) and wavelength coverage (Δλ in nm) of the spectra, and the name of the observatory (country,eastern longitude in degrees, northern latitude in degrees, altitude in m).

Figure 1. Overview of the nights allocated to our multi-site campaigns so far. Green denotes that at least
one usable observation has been taken that night, red means that no observations could be done, blue
denotes extra time obtained by our collaborators, and black is an upcoming allocated night.

2. OBSERVATION STRATEGY

To study the g-modes in full detail (expected periods between 0.3 and 3 days), we need a long
timebase covered with observations every few hours. To additionally check if short-term p-mode
like variations are present (expected periods of a few hours), we need groups of consecutive
exposures with short integration times. Therefore we currently observe in two modes:
Low cadence mode for spectrographs with small wavelength coverage where a single exposure hasS/N ≥ 200 and exposure time ≤ 1 hour. Bright targets with exposure times ≤ 10 min are observed ingroups of 5 consecutive spectra to search for p-modes.
High cadence mode for spectrographs with a large wavelength coverage where groups of five S/N≥ 90 spectra are taken each with exposure time ≤ 10 min. LSD profiles (Donati et al., 1997,MNRAS 291, 658) are used to study the high p-mode frequencies and individual lines are used tostudy the lower g-mode frequencies.

-----------------------------------------------------------------------------------------------------------------ReferenceRObservatory
Δλ(country, long, lat, alt)-----------------------------------------------------------------------------------------------------------------9682M@DAO/1.2-m
60,000Dominion Astronomical Observatory
625-645(Canada, -123, 49, 230)
RA2@McD/2.1-m
60,000
McDonald Observatory
540-660(Texas USA, -104, 31, 2026)
HARPS@ESO/3.6-m
120,000
European Southern Observatory
378-691(La Silla Chile, -71,-29, 2347)
FEROS@ESO/2.2-m
48,000European Southern Observatory
370-900(La Silla Chile, -71,-29, 2347)
HERMES@ENO/1.2-m
85,000
Roque de los Muchachos Observatory
377-900(La Palma, -18, 29, 2326)
SOPHIE@OHP/1.93-m
40,000Observatory de Haute Provence
388-694(France, 6, 44, 665)
CES@TAUT/2.0-m
67,000Karl Schwarzchild Observatory472-740(Germany, 12, 51, 331)
GIRAFFE@SAAO/1.9-m 35,000
South African Astronomical Observatory
380-1050(South Africa, 21,-32, 1771)
COUDE@XING/2.16-m
35,000
Xinglong Observatory
560-900(China, 118, 40, 950)
BOES@BOA/1.8-m
90,000Bohyunsan Optical Astronomical Observatory
381-810(Korea, 129, 36, 1127)
HIDES@OAO/1.88-m
50,000
Okayama Astrophysical Observatory400-775(Japan, 134, 35, 372)
HERCULES@MJUO/1.0-m 45,000
Mount John University Observatory
380-900(New Zealand, 170,-44, 1027)------------------------------------------------------------------------------------------------------------------In Table 1, we list the number observations obtained so far in the low cadence mode are given incolumn #LC, and those in high cadence mode in column #HC., we also list the number of HIDES
spectra taken in column #HIDES to highlight the large contribution made to the project by theOAO.
Table 1. Overview of all the targets that were selected for our spectroscopic multi-site campaigns. For eachtarget, we give the HD number, right ascension, declination, spectral type, the mean magnitude in theJohnson V filter, the projected rotational velocity, pulsational classification, starting year of the multi-site
campaign, the number of observed spectra in the high and low cadence mode and the number of spectra
taken with HIDES. The targets marked with * are observable with an airmass below 2.0 from all theinvolved observatories.
---------------------------------------------------------------------------------------------------------------------------HDnralpha2000 delta2000
SpT
V Bin vsini class year
#LC #HC #HIDES---------------------------------------------------------------------------------------------------------------------------12901
40745
55892
65526*
112429135825139095147787
167858*182640*18963121839602 06 10.7 -10 16 34
06 00 17.7 -12 54 00
07 12 33.6 -46 45 33
07 59 03.0 -04 20 00
12 55 28.5 +65 26 19
15 15 32.2 -10 30 02
15 37 16.9 -32 03 26
16 27 57.3 -64 03 29
18 17 04.9 +01 00 21
19 25 29.9 +03 06 53
20 02 40.8 -41 25 04
23 07 28.7 +21 08 03

F0F2IVF0IV
A3F0IV-V
F0
F0V
F4IV
F2VF0IV
F0V
A5V

6.7646.2
40
4.5547.056
5.2101
7.338
7.965
5.3 SB2 8+25
6.6 SB1 5
3.4857.5446.038γDorγDorγDorγDorγDorγDorγDorγDorγDorγDorγDorγDor2009
2008
earlier20092009
2009
earlier
2007
20072009
2007
2008

34525044273
69333 464
10 368855300527 1067
22 33098 278131 3131857421071
03 25 57.4 +49 07 15 B7V
6.1
62 SPB 2008 159 128
9225558* 04 03 44.6 +05 26 08 B3V
5.322 SPB 2008 170
995928114* 04 26 21.1 +08 35 25 B6IV
6.1
11 SPB 2009
212525182255 19 22 50.9 +26 15 45 B6III
5.2 SB1 14 SPB 200970 24251----------------------------------------------------------------------------------------------------------------------------Figure 2. To demonstrate the variability of some of our targets, and the quality of the data we are able tocollect we show the Si II 6347Å profiles for HD21071 (left) and HD25558 (middle) and the LSD profiles for
HD218396 (right) all taken from HIDES@OAO/1.88-m, phased to each stars strongest photometricfrequency.

3. ORGANISED MULTI-SITE CAMPAIGNSOur first aim is to focus on each selected target (Table 1) initially for one year and to analyse theobtained data with already existing older data. The most promising targets will be selected for verylong-term monitoring. So far, we have organised 3 multi-site campaigns: campaign 1 in spring of2007 and 2008 for 3 γDor stars (HD147787, HD167858, HD189631), campaign 2 in fall 2008 for 2
SPB stars (HD21071, HD25558) and the planet hosting γDor star HD218396, and campaign 3 in2009 for 2 SPB stars (HD28114, HD182255) and 6 γDor stars (HD12901, HD40745, HD65526,HD112429, HD135825, HD182640). An overview of the nights allocated to our multi-site campaign
is given in Fig. 1. The analysed HIDES@OAO/1.88-m observations obtained during campaign 2 arepresented in Fig. 2, showing clear line profile variations for all objects. For each of the stars, thevisible variations appear consistent with one of the frequencies known from photometry.

CONCLUSIONS & FUTURE

So far, we have collected 150+ spectra for 8 stars. We are now analysing these data and will use theresults to establish a few well characterised stars for both the γDor and SPB classes, which are sorelyneeded. We also hope to better understand the problems encountered thus far with modeidentification of these g-mode pulsations, and will to try to improve on the current mode
identification methods for these stars.