CI Aql = Nova Aql 1917, 2000

Kesao Takamizawa (Japan) reported a possible nova on Apr. 28.67 UT, which has been identified with the old "nova" CI Aql (Nova Aql 1917). The follow-up spectroscopy revealed that the star is a recurrent nova, such as, e.g., T CrB or RS Oph. Below are the high-resolution H-alpha profiles obtained on three epochs in May, 2000. Note the evolution of the P Cygni-profile suggesting an outflow velocity of 2500 km/s. Also, some additional features suggest a complex structure for the ejecta. The strong diffuse interstellar band (DIB) at 6613 A implies a considerably high reddening.

Light curve of CI Aql
The epochs of spectroscopic observations are marked in the visual light curve based on observations collected by the VSNET group (

Spectra of CI Aql
These spectra were taken in the course of a research program headed by Laszlo Kiss at University of Szeged, Szeged, Hungary in collaboration with Jim Thomson and Waldemar Ogloza (visiting astronomer from Poland). Previous results of this project can be found in Kiss & Thomson, 2000, A&A 355, L9-L12.

Laszlo Kiss, May 2000