Abstract
Photometric I band light curves of 21 ultra cool M and L dwarfs are presented. Variability with amplitudes of 0.01 to 0.055 magnitudes (RMS) with typical timescales of an hour to several hours are discovered in half of these objects. Periodic variability is discovered in a few cases, but interestingly several variable objects show no significant periods, even though the observations were almost certainly sensitive to the expected rotation periods. It is argued that in these cases the variability is due to the evolution of the surface features on timescales of a few hours. This is supported in the case of 2M1145 for which no common period is found in two separate light curves. It is speculated that these features are photospheric dust clouds, with their evolution possibly driven by rotation and turbulence. An alternative possibility is magnetically-induced surface features. However, chromospheric activity undergoes a sharp decrease between M7 and L1, which may be related to the observed greater occurrence of variability in objects later than M9.
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C.A.L. Bailer-Jones, R. Mundt: A&A 348, 800 (1999)
C.A.L. Bailer-Jones, R. Mundt: A&A submitted (2000)
G. Basri, Cool Stars 11 (ASP Conf. Ser.), in press (2000)
G. Basri, S. Mohanty, F. Allard, et al.: ApJ 538, 363 (2000)
V.J.S. Béj ar, M.R. Zapatero Osorio, R. Rebolo: ApJ 521, 671 (1999)
A.J. Burgasser, J.D. Kirkpatrick, M.E. Brown, et al.: AJ 120, 1100 (2000)
A. Burrows, CM. Sharp: ApJ 512, 843 (1999)
G. Chabrier, I. Baraffe: ARAA, in press (2000)
G. Chabrier, I. Baraffe, F. Allard, P. Hauschildt: ApJ 542, 464 (2000)
T.J. Deeming: Astrophysics & Space Science 36, 137 (1975)
X. Fan, G.R. Knapp, M.R. Strauss, et al.: AJ 119, 928 (2000)
J.E. Gizis, D.G. Monet, I.N. Reid, J.D. Kirkpatrick, J. Liebert, R.J. Williams: AJ 120, 1085 (2000)
H.R.A. Jones, T. Tsuji: ApJ 480, L39 (1997)
J.D. Kirkpatrick, I.N. Reid, J. Liebert, et al: ApJ 519, 802 (1999)
J.D. Kirkpatrick, I.N. Reid, J. Liebert, et al., AJ 120, 447 (2000)
D.W. Koerner, J.D. Kirkpatrick, M.W. McElwain, N.R. Bonaventura: ApJ 526, L25 (1999)
S.L. Leggett, T.R. Geballe, X. Fan, et al.: ApJ 536, L45 (2000)
H.J. Lehto: private communication (2000)
K. Lodders: ApJ 519, 793 (1999)
E.L. Martín, G. Basri, M.R. Zapatero-Osorio, R. Rebolo, R.J. García López: ApJ 507, 41 (1998)
E.L. Martín, X. Delfosse, G. Basri, B. Goldman, T. Forveille, M.R. Zapatero-Osorio: ApJ 118, 2466 (1999)
T. Nakajima, T. Tsuji, T. Maihara, et al.: PASJ 52, 87 (2000)
K.S. Noll, T.R. Geballe, S.K. Leggett, M.S. Marley: ApJ 541, L75 (2000)
R. Rebolo, M.R. Zapatero Osorio, E.L. Martín: Nature 377, 129 (1995)
I.N. Reid, J.D. Kirkpatrick, J.E. Gizis, et al.: AJ 119, 369 (2000)
R. Rebolo, E.L. Martfn, G. Basri, G.W. Marcy, M.R. Zapatero-Osorio: ApJ 469, L53 (1996)
D.H. Roberts, J. Lehar, J.W. Dreher: AJ 93, 968 (1987)
D.M. Terndrup, A. Krishnamurthi, M.H. Pinsonneault, J.R. Stauffer: ApJ 118, 1814 (1999)
C.G. Tinney, A.J. Tolley: MNRAS 304, 119 (1999)
M.R. Zapatero Osorio, R. Rebolo, E.L. Martin, et al.: A&AS 134, 537 (1999)
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Bailer-Jones, C.A.L. (2001). Surface Features, Rotation and Atmospheric Variability of Ultra Cool Dwarfs. In: Jones, H.R.A., Steele, I.A. (eds) Ultracool Dwarfs. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-56672-1_9
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DOI: https://doi.org/10.1007/978-3-642-56672-1_9
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