stars: variables: general; stars: oscillations; stars: individual: HD 12901; HD 48501; line: profiles
Abstract :
[en] We gathered long-term multicolour Geneva UB[SUB]1[/SUB]BB[SUB]2[/SUB]V[SUB]1[/SUB]VG photometric and high-resolution (R=40 000) spectroscopic data of the two gamma Doradus stars HD 12901 and HD 48501. The photometry reveals three frequencies for each of the two stars: f[SUB]1[/SUB]=1.21563 c d[SUP]-1[/SUP], f[SUB]2[/SUB]=1.39594 c d[SUP]-1[/SUP] and f[SUB]3[/SUB]=2.18636 c d[SUP]-1[/SUP] for HD 12901 and f[SUB]1[/SUB]=1.09408 c d[SUP]-1[/SUP], f[SUB]2[/SUB]=1.29054 c d[SUP]-1[/SUP] and f[SUB]3[/SUB]=1.19924 c d[SUP]-1[/SUP] for HD 48501. The photometric amplitude is each time largest in the Geneva B[SUB]1[/SUB] filter and the variations in all the different filters are perfectly in phase within the measurement errors. Mode identification points out that the six modes are all l=1 modes and that the non-adiabatic temperature variations are extremely small, in contradiction to current theoretical predictions. Our spectra show that all the observed frequencies are intrinsic to the stars and cannot be due to binarity. We detect clear line-profile variations at low amplitude (<1 km s[SUP]-1[/SUP]) due to the oscillations of both targets. The estimated v sin i from the spectra are Ë 53 km s[SUP]-1[/SUP] for HD 12901 and Ë 29 km s[SUP]-1[/SUP] for HD 48501. It is at present unclear if the triplet-like structure for HD 48501 is the consequence of rotational splitting or of the large separation expected for high-order gravity modes in the asymptotic regime. Based on observations gathered with the Swiss 0.7 m telescope equipped with the photometer P 7 and with the Swiss 1.2 m Euler telescope equipped with the spectrograph CORALIE, both situated at La Silla, Chile. Reduced data available upon request from the first author.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Aerts, C.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
Cuypers, J.; Royal Observatory, Ringlaan 3, 1180 Brussel, Belgium
De Cat, P.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
Dupret, Marc-Antoine ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique
De Ridder, J.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
Eyer, L.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium ; Princeton University Observatory, Princeton, NJ 08544, USA
Scuflaire, Richard ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Evol. et stabilité des étoiles et des amas d'étoiles (ESEA)
Waelkens, C.; Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
Language :
English
Title :
Long-term multicolour photometry and high-resolution spectroscopy of the two gamma Doradus stars HD 12901 and HD 48501
Breger, M., Garrido, R., Handler, G., et al. 2002, MNRAS, 329, 531
Breger, M., Handler, G., Garrido, R., et al. 1997, A&A, 324, 566
Breger, M., Pamyatnykh, A. A., Pikall, H., & Garrido, R. 1999, A&A, 341, 151
Cuypers, J. 1987, The Period Analysis of Variable Stars, Academiae Analecta, Royal Academy of Sciences, 49, 3, Belgium
De Cat, P., & Aerts, C. 2002, A&A, 393, 965
Dupret, M.-A., De Ridder, J., De Cat, P., et al. 2003, A&A, 398, 677
Eyer, L. 1998, Ph.D. Thesis, Geneva Observatory, Switzerland
Eyer, L., & Aerts, C. 2000, A&A, 361, 201
Eyer, L., Aerts, C., van Loon, M., Bouckaert, F., & Cuypers, J. 2002, in Observational Aspects of Pulsating B- and A Stars, ed. C. Sterken, & D. W. Kurtz, ASP Conf. Ser., 256, 203
Fekel, F. C., Warner, B., & Kaye, A. B. 2003, AJ, 125, 2196
Garrido, R. 2000, in Delta Scuti and Related Stars, Reference Handbook and Proc. 6th Vienna Workshop in Astrophysics, ed. M. Breger, & M. Montgomery, ASP Conf. Ser., 210, 67
Guzik, J., Kaye, A. B., Bradley, P. A., et al. 2000, ApJ, 542, L57
Handler, G. 1999, MNRAS, 309, L19
Handler, G. 2002, http://www.astro.univie.ac.at/~gerald/gdorlist.html
Handler, G., & Aerts, C. 2003, in Variable stars in the local group, ed. D. W. Kurtz, & K. Pollard, ASP Conf. Ser., in press
Handler, G., & Shobbrook, R. R. 2002, MNRAS, 333, 251
Henry, G. W., & Fekel, F. C. 2002, PASP, 114, 988
Krisciunas, K. 1998, in New Eyes to See Inside the Sun and Stars: Pushing the Limits of Helio- and Asteroseismology with New Observations from Ground and from Space, ed. F. L. Deubner, J. Christensen-Dalsgaard, & D. W. Kurtz (Kluwer Academic Publishers), 339
Löffler, W. 2002, in Asteroseismology Across the HR Diagram, ed. M. J. Thompson, M. H. Cunha, & M. J. P. F. G. Monteiro (Kluwer Acdemic Publishers), 529
Mantegazza, L., Poretti, E., Bossi, M., & Zerbi, F. M. 1995, in Astrophysical applications of stellar pulsation, ed. R. S. Stobie, & P. A. Whitelock, ASP Conf. Ser., 83, 339
Mathias, P., Chapellier, E., Le Contel, J.-M., et al. 2003, in Asteroseismology across the HR diagram, ed. M. J. Thompson, M. H. Cunha, & M. J. P. F. G. Monteiro (Kluwer Academic Publishers), 359
Poretti, E., Koen, C., Bossi, M., et al. 2002, A&A, 384, 513
Roberts, D. H., Lehár, J., & Dreher, J. W. 1987, AJ, 238, 946
Scargle, J. D. 1982, ApJ, 263, 835
Stellingwerf, R. F. 1978, ApJ, 224, 953
Zerbi, F. M. 2000, in Delta Scuti and related Stars, 6th Vienna Workshop in Astrophysics, ed. M. Breger, M. H. Montgomery, ASP Conf. Ser., 201, 332