Central Bureau for Astronomical Telegrams
IAUC 7787: 1999 TC_36; 2001is, 2001it
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Circular No. 7787
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Phone 617-495-7440/7244/7444 (for emergency use only)
1999 TC_36
C. A. Trujillo and M. E. Brown, California Institute of
Technology, report the discovery of a companion to the plutino 1999
TC_36 (MPEC 1999-Y19, 2000-O37; MPO 20742). Observations were
collected on two dates, the first spanning about 45 min centered on
2001 Dec. 8.906 UT and the second on Dec. 9.307, as part of an
ongoing survey for transneptunian binaries undertaken with the
Hubble Space Telescope STIS instrument. Separations of 0".3651 +/-
0".0011 in p.a. 2.0 +/- 0.1 deg and 0".3698 +/- 0".0007 in p.a. 3.7
+/- 0.1 deg were measured for the two dates, respectively. At a
geocentric distance of 31.16 AU, this separation corresponds to at
least 8000 km between components. The pair exhibit a flux
difference of 2.21 +/- 0.01 magnitudes in the unfiltered images.
Recovery observations are necessary for companion orbit
determination; however, due to the close proximity and large flux
difference between the primary and companion, uncorrected ground-
based recovery is likely to be difficult.
This report provides an opportunity to correct a misconception
on IAUC 7749. In referring to IAUC 7733, it was suggested that
2001 QT_297 is a plutino, whereas it is more likely to be a
cubewano.
SUPERNOVAE 2001is AND 2001it
T. Matheson, S. Jha, P. Challis, and R. Kirshner, Harvard-
Smithsonian Center for Astrophysics, report that a spectrum (range
370-750 nm) of SN 2001it (cf. IAUC 7782), obtained by M. Calkins on
Jan. 6.55 UT with the F. L. Whipple Observatory 1.5-m telescope (+
FAST spectrograph), shows it to be a type-II supernova. Weak P-Cyg
lines of hydrogen are apparent on a relatively blue continuum.
S. Benetti, G. Altavilla, A. Pastorello, M. Turatto, S.
Desidera, and E. Giro, Osservatorio Astronomico di Padova; and E.
Cappellaro, Osservatorio Astronomico di Capodimonte, write: "A
spectrum (range 400-780 nm, resolution 2.5 nm) of SN 2001is (cf.
IAUC 7782), obtained on Jan. 8.86 UT with the Asiago 1.82-m
telescope (+ AFOSC), shows it to be a type-Ib supernova, 2-3 weeks
after maximum. The spectrum closely resemble those of the type-Ib
SN 1999dn, which has a residual hydrogen contamination in the
spectra (Branch et al. 2002, Ap.J., in press). We also observed
SN 2001it, whose spectrum is that of a type-II supernova around
maximum; H-alpha shows a broad emission feature, without
absorption, from which an expansion velocity (FWHM) of about 10 500
km/s is derived."
(C) Copyright 2002 CBAT
2002 January 10 (7787) Daniel W. E. Green
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