NOVA ERIDANI 2009 - Update

According to the Cbets 2053 & 2055 the transient in Eridanus has been spectroscopically confirmed as a nova. Spectra obtained on Nov. 26 by H. Maehara (Kyoto University) and by M. Fujii (Okayama) shows that the object seems likely to be an He/N-class nova.

This nova has been designated NOVA ERIDANI 2009.

Moreover another spectrum obtained by NASA researchers using the Aerospace Near-Infrared Imaging Spectrograph on the 3-m Shane reflector of Lick Observatory shows very strong, broad emission lines and confirm this object as a nova.

In the meantime prediscovery measurements of Nova Eridani 2009 have been reported on VSNET mailing list by "Pi of the Sky” team.

According to their measurement the nova reached the magnitude 5.60 (R-filter) on Nov. 15:

20091113.301 7.10 R "Pi of the Sky"

20091114.304 5.71 R "Pi of the Sky"

20091115.308 5.60 R "Pi of the Sky"

20091116.302 5.92 R "Pi of the Sky"

20091117.297 6.09 R "Pi of the Sky"

ASAS-3 system (Pojmanski 2002, Acta. Astron. 52, 397) also detected this object at the following V magnitudes:

Nov. 10.236 UT, [14.0:

Nov. 19.241, 7.34;

Nov. 22.179, 7.98;

Nov. 24.269, 8.12.

by Ernesto Guido

POSSIBLE NOVA IN ERIDANUS

Following the posting on the Central Bureau's unconfirmed-objects webpage & Cbet No. 2050 about the discovery by K. Itagaki (Yamagata, Japan) of a possible Nova in Eri we performed some follow-up of this object remotely through a 0.25-m, f/3,4 reflector +CCD, from GRAS Observatory (near Mayhill, NM).

On our images taken on November 26.36 we can confirm the presence of an optical counterpart with unfiltered CCD magnitude about 8.2 (UCAC2 Catalogue reference stars) at coordinates:

R.A. = 04 47 54.12, Decl.= -10 10 43.1

(equinox 2000.0; UCAC2 catalogue reference stars).

Our image:

A comparison with a DSS red plate (limiting magnitude about 20), obtained on 1990, Nov. 23, shows the proximity of a 15th-mag star to the position of the possible nova in Eri. This is an animation showing our image and the DSS plate:

On the Cbet Yamaoka (Kyushu University) suggests that it might be the brightening of the 15th-mag blue star noting "that the amplitude of seven magnitudes is rather large for a dwarf nova, but somewhat small for a rapid classical nova".

Spectroscopic and time-resolved photometric observations are required to understand the real nature of this transient.

UPDATE

For an update about this object please see our Nov. 27, 2009 post:

http://remanzacco.blogspot.com/2009/11/nova-eridani-2009-update.html

by Ernesto Guido and Giovanni Sostero