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IM Nor: call for observations (Hachisu et al.)
The following message is from Hachisu-san (University of Tokyo), who
has been studying IM Nor as a joint program with the VSNET team.
IM Nor is now experiencing an exciting stage, and we call for intensive
time-resolved observing campaign.
Other basic information on IM Nor on VSNET include:
* Kato et al. (2002) A&A 391, L7 (first paper on IM Nor by the VSNET team,
suggesting the possibility of eclipses), preprint available on the website.
* http://vsnet.kusastro.kyoto-u.ac.jp/vsnet/Novae/imnor.html
(VSNET page; use this for correct identification)
Those who contribute time-resolved observations (orbital light curves)
to this campaign will be, in principle, included as co-authors of the
planned paper by Hachisu et al.
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IM Nor --- observing campaign
Woudt and Warner published very interesting orbital light curves
of the recurrent nova IM Nor (astro-ph/0304002). They showed
periodic dips in brightness and concluded that the orbital period is
2.462 h, as short as T Pyx, another very short orbital period
recurrent nova. IM Nor has already decayed to V=16.5 mag but
still 1.5-2.0 mag brighter than the quiescent level.
At the present stage, the accretion disk, which is irradiated by
the hot white dwarf, dominates in visual light. If we follow
the changes of orbital light curve shapes from time to time,
we are able to catch the geometrical structure change of the disk
and also the decay of the hydrogen burning on the white dwarf.
This is a very rare opportunity and definitely important
for the recurrent nova physics. We request to observe IM Nor
as long as possible and send us the data.
We are now modeling the recurrent nova IM Nor by fitting both the
overall (decline from the peak to the quiescence) light curve
and the orbital light curves at each stage.
We expect that the orbital modulations of IM Nor are reproduced by
an eclipsing model for an inclination angle of 70-75 degree,
although its eclipse depth is as shallow as 0.3 mag.
However, we need more data to construct a comprehensive model
of IM Nor.
with best wishes,
Izumi Hachisu
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Department of Earth Science and Astronomy
College of Arts and Sciences, University of Tokyo
Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
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TEL: +81-3-5454-6615 FAX: +81-3-3465-3925
e-mail: hachisu@chianti.c.u-tokyo.ac.jp
WWW: http://grape.c.u-tokyo.ac.jp/~hachisu/index.shtml
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