Long period variables in the globular cluster 47 Tuc: Radial velocity variations

• Published in: Astronomy and astrophysics (Berlin) Vol. 432; no. 1; pp. 207 - 217
• Main Authors: Lebzelter, T., Wood, P. R., Hinkle, K. H., Joyce, R. R., Fekel, F. C.
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.03.2005
• Subjects: stars: AGB and post-AGB; stars: evolution; stars: late-type; Circumstellar dust; stars: evolution; Light curves; Luminosity; Mass loss; Loss rate; stars: AGB and post-AGB; Globular clusters; Long period variable star; stars: late-type; Radial velocity; Infrared excess; Large Magellanic Cloud
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361:20047164

We present near infrared velocity curves for 12 long period variables (LPVs) in the globular cluster 47 Tuc (NGC 104). New light curves are also presented for these variables. Results are compared with the period-luminosity sequences occupied by the LPVs in the LMC. Sequence C variables (fundamental mode pulsators) have larger velocity amplitudes than sequence B variables (first overtone pulsators). We show that, at similar luminosities, higher mass loss rates are associated with larger pulsation amplitudes. One variable (V18) does not fit the normal period luminosity sequences and it has an unusually large amount of circumstellar dust, suggesting that it has recently undergone a thermal pulse on the AGB. Finally, we report the discovery of three new long period variable stars in the cluster core, all previously found to have a large infrared excess.