Central Bureau for Astronomical Telegrams
IAUC 9082: OUTBURST OF R71 IN THE LMC
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Circular No. 9082
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
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OUTBURST OF R71 IN THE LARGE MAGELLANIC CLOUD
R. Gamen, Instituto de Astrofisica de La Plata, CONICET; R.
Barba, Universidad de La Serena and Insituto de Ciencias
Astronomicas y de la Tierra, CONICET, San Juan; N. Walborn, Space
Telescope Science Institute (STScI); A. Bonanos, Institute of
Astronomy and Astrophysics, National Observatory of Athens; N.
Morrell, Las Campanas Observatory (LCO), Carnegie Observatories; D.
Lennon, European Space Agency and STScI; G. Ferrero, Facultad de
Ciencias Astronomicas y Geofisicas, Universidad Nacional de La
Plata; G. Preston, Carnegie Observatories; and E. Schkolnik,
Department of Terrestrial Magnetism, Carnegie Institution, write
that in early Aug. 2009, A. Jones (Nelson, New Zealand) reported an
unusual visual brightening of the luminous blue variable HDE 269006
(= R71) in the Large Magellanic cloud to visual mag 9. Inspection
of the ASAS-3 photometric database (ASAS 050207-7120.2) shows that
the unusually gradual rise in the light curve of R71 started
approximately 5 years ago, albeit with some oscillations during
that time, becoming steeper over the last 1300 days; the latest
outburst was first reported via vsnet by P. Williams in Mar. 2008
and T. Kato in Apr. 2008 based on visual observations and the
ASAS-3 photometric database, and by Munari et al. (2009, A.Ap. 503,
511), who noted that R71 had brightened to V = 9.97 and that RAVE
spectroscopy in Feb. 2008 showed it to be similar to an early-A
supergiant. After a bright maximum in 1975 (V approximately 9.9),
the star had faded to V about 10.8-11.0.
R71 is now visually the brightest star in the LMC. Follow-up
spectroscopic observations obtained at Complejo Astronomico El
Leoncito on Aug. 9 by Ferrero, and at LCO by Schkolnik on Aug. 20
and 24 and by Preston on Aug. 26, showed that the spectrum of R71
resembles that of an extreme early-F-type hypergiant. This
spectrum is significantly cooler than that previously seen at the
maximum state in 1970-1977, when the system reached an A1 Ieq
spectral type (Thackeray 1974, MNRAS 168, 221; Wolf et al. 1981,
A.Ap. 103, 94). Currently the spectrum of R71 displays a populous
set of sharp and deep absorption lines of singly ionized and
neutral metals characteristic of an F0 Ia spectrum. Narrow and
distinctive P-Cyg profiles in H_alpha, H_beta, Fe II (multiplet 42),
and Ca II infrared triplet emission lines are also present. This
high-state spectrum is unprecedented in R71 and, together with the
unprecedented visual magnitude, indicates an extreme outburst in
this LBV star, with the characteristic conservation of the
bolometric magnitude.
(C) Copyright 2009 CBAT
2009 October 14 (9082) Daniel W. E. Green
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