Central Bureau for Astronomical Telegrams
IAUC 3823: HH 57 IRS 8; GD 356 = Gr 329 = LP 137-43
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Circular No. 3823
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
HH 57 IRS 8
B. Reipurth, University Observatory, Copenhagen: and J.
Krautter, Max-Planck-Institut fur Extraterrestrische Physik,
Garching, report: "The newly-brightened object that Graham (IAUC
3785, 3792) has identified with the infrared source HH 57 IRS 8
(Reipurth and Wamsteker 1983, A.Ap. 119, 14) was observed
spectroscopically by us on 1981 June 4.2 UT. The 59-A/mm red image-
dissector-scanner spectrum obtained with the European Southern
Observatory's 3.6-m telescope reveals a slightly red continuum
with two pronounced features: H-alpha is in absorption and blueshifted
by ~ 200 km/s, and the Li I 671-nm absorption is strong and broad.
This spectral appearance, together with the large brightening
noted by Graham, is consistent with a star undergoing an FU-Ori-
type eruption. We conclude that the event occurred or was well
underway at least two years ago."
GD 356 = Gr 329 = LP 137-43
J. L. Greenstein, Palomar Observatory, communicates: "Seven
Palomar 0.5-nm-resolution spectra of this high-latitude, unique-
spectrum white dwarf (Giclas et al. 1967, Lowell Obs. Bull. 7, No.
4: Greenstein 1974, Ap.J. 189, L131; Luyten 1977, White Dwarfs II,
Univ. Minn.), at R.A. = 16h39m49s, Decl. = +53deg46'9 (equinox 1950.0;
mag 15.1: mu = 0".24/yr, distance 30-50 pc), were obtained on five
nights in 1982 and 1983 (the latter courtesy Oke and Sargent).
These show constant, 5-nm-wide, triple, weak-emission HS and H&,
not Doppler-shifted, but consistent with centroids of hydrogen in
a magnetic field of 10 MG (Kemic 1974, JILA Rep. No. 113). There
is no magnetic field in the continuum (Angel et al. 1981, Ap.J.
Suppl. 45, 457), but no other white-dwarf emission regions are
known in so strong a field. The fluxes on four multichannel
spectra are nearly flat at 3 mJy, and there is no red excess to 850
nm. A model at 7500 K fits the data, but the radius is somewhat
large. The emission volume has a radius from 75 to 0.7 times that
of a white dwarf, at electron densities 10**10 to 10**13. GD 356 is
not a known x-ray, infrared or radio source. If the emission
region surrounds an accretion disk, the underlying magnetic field
is very large. If in a disk, the fixed Zeeman pattern requires
either zero or rapid spin of the magnetic axis. A hot, magnetized
corona is possible. High-time-resolution photometry and
observations at other wavelengths are needed."
1983 June 8 (3823) Brian G. Marsden
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