Similarly to the post for GG Car, I though that it is better to keep a track of all papers I find for my sample. As far as Hen 3-298 (Simbad) the results are not that many!
- 1966 / Wray, J. D. 1966(PhD thesis, Northwestern University)
First detection as an Hα emission star. - 1976 / Henize, K. G. 1976 (ApJS, 30, 491)
Also included in this catalog for Hα emission stars in the Southern Skies. - 1986 / Olnon, F. M.; Raimond, E.; Neugebauer, G.; van Duinen, R. J.; Habing, H. J.; Aumann, H. H.; Beintema, D. A.; Boggess, N.; Borgman, J.; Clegg, P. E.; Gillett, F. C.; Hauser, M. G.; Houck, J. R.; Jennings, R. E.; de Jong, T.; Low, F. J.; Marsden, P. L.; Pottasch, S. R.; Soifer, B. T.; Walker, R. G.; Emerson, J. P.; Rowan-Robinson, M.; Wesselius, P. R.; Baud, B.; Beichman, C. A.; Gautier, T. N.; Harris, S.; Miley, G. K.; Young, E. 1986 (A&A, 65, 607)
Detected as an IR excess source. - 1994 / The, P. S.; de Winter, D.; Perez, M. R. 1994 (A&AS, 104, 315)
Included in this catalog as an emission line star. - 2005 / Miroshnichenko, A. S.; Bjorkman, K. S.; Grosso, M.; Hinkle, K.; Levato, H.; Marang, F. 2005 (A&A, 436, 653)
The first dedicated study of Hen 3-298. They identified double-peaked emission lines, such as Hα with a stronger red peak, and the [CaII] doublet. [OI] lines were found single-peaked. They also detected CO features in emission and estimated the temperature ~2000 K, suggesting that originates from a dust free zone, inside but close to the dusty disk. Moreover, they estimate log L/L☉∼ 5.1 and a spectral type of no earlier than B3, at a distance of 3-4.5 kpc. Suggesting a supergiant nature. - 2013 / Oksala, M. E.; Kraus, M.; Cidale, L. S.; Muratore, M. F.; Borges Fernandes, M. 2013 (A&A, 558A, 170)
Part of the IR survey. Detecting and studying the CO features (also estimating ~2000 K), and estimating the ratio 12CO/13CO=20±5 (consistent with supergiants; Kraus 2009).