Table 2
Summary of optical spectra of Var C.
| Date | JD | Features | Spectral type | Ref. |
|
|
||||
| 30 Nov. 1946 | 2 432 155 | Ca ii K and Ca ii H in absorption with | later than F0 | 1 |
| nearly equal strength | ||||
| Hγ and Hδ weakly in absorption | ||||
| 23 Aug. 1947 | 2 432 421 | Ca ii K and Ca ii H in absorption with | later than F0 | 1 |
| nearly equal strength | ||||
| 24/25 July–22 Sept. 1949 | 2 433 122–2 433 182 | faint Hβ in emission | 1 | |
| 3 Aug.–28/31 Oct. 1951 | 2 433 862–2 433 951 | Hβ and Hγ in emission | late A-typea | 1 |
| Ca ii K and Ca ii H in absorption | ||||
| 29 Nov. 1951 | 2 433 980 | Hβ and Hγ in emission | 1 | |
| 27/28 Sept. 1973 | 2 441 953 | bright Hα in emission | 2 | |
| 14 Oct.–10 Nov. 1974 | 2 442 335–2 442 362 | several hydrogen, He i Fe ii, | late B-typea | 3 |
| and [Fe ii] lines in emission | ||||
| Ca ii K in absorption | ||||
| Aug. 1976 | ≈2 443 006 | compared to previous spectrum: | early B-typea | 4 |
| hydrogen and He i emission lines weaker | ||||
| some of the Fe ii and [Fe ii] lines no longer seen | ||||
| 10/11 Nov. 1983 | 2 445 649.5 | Hα, Hγ and numerous Fe ii lines in emission | A-typea | 5 |
| all with P-Cygni profiles | ||||
| strong Mg iiλ4481 in absorption | ||||
| Nov.–Dec. 1985 | ≈2 446 385–≈2 446 415 | Hα and Hβ in emission | F0Ia–F5Ia | 6 |
| several strong Fe ii and | ||||
| ionised metal lines in absorption | ||||
| I(Ca ii K) >I(Ca ii H + Hϵ) | ||||
| Aug.–Sept. 1986 | ≈2 446 658–≈2 446 689 | weaker metallic lines | A2–A3 | 6 |
| I(Ca ii H + Hϵ) >I(Ca ii K) | ||||
| 15/16/17 Sept. 1987 | 2 447 054–2 447 056 | Fe ii and other metallic lines in absorption | A-type | 6 |
| several Fe ii-lines in emission | ||||
| Hα, Hβ, and Hγ showed P-Cygni profiles | ||||
| 3/6 Oct.–13 Dec. 1992 | 2 448 899–2 448 970 | weak He i lines in absorption | late B-typea | 7 |
| compared to previous spectra: | ||||
| hydrogen and Fe ii emission lines getting stronger | ||||
| 14/15 Dec. 1993 | 2 449 336.5 | pronounced hydrogen lines in emission | late B-typea | 8 |
| several Fe ii and [Fe ii] lines in emission | ||||
| weak He i line | ||||
| 30 Nov. 2003 | 2 452 974 | Hβ in emission and numerous metallic lines | F0Ia–F5Ia | 9 |
| in absorption | ||||
| 13 Nov. 2004 | 2 453 323 | Hα, Hβ, and Hγ in emission, some weak Fe i | A-type | 10 |
| lines in absorption or emission | ||||
| 7/8 Dec. 2004–16 Jan. 2005 | 2 453 347–2 453 387 | strong hydrogen lines in emission | B[e] | 11 |
| several Fe ii and [Fe ii] lines in emission | ||||
| 22 Oct. 2008 | 2 454 762 | Hα and Hβ, in emission, some He i lines and | B-type | 10 |
| several Fe i lines in emission | ||||
| 29 Sept.–2 Oct. 2010 | 2 455 469–2 455 472 | Hα, Hβ, and Hγ in emission, several He i and | B-typea | 9 |
| Fe ii lines in emission, P-Cygni profiles | ||||
| 3 Oct. 2010 | 2 455 473 | hydrogen, He i, Fe ii, and [Fe ii] lines in emission, | B1–B2 | 12 |
| P-Cygni profiles | ||||
| 18 Sept. 2013 | 2 456 554 | hydrogen lines in emission | A-typea | 13 |
| 5 Oct. 2013 | 2 456 571 | Fe ii, [Fe ii], and strong hydrogen lines in emission, | late B-typea | 14 |
| P-Cygni profiles | ||||
| He i very weakly in absorption | ||||
| 7 Oct. 2013 | 2 456 573 | hydrogen in emission (weaker than in 10/2010), | late A-type | 12 |
| Ca ii and Mg ii in absorption, | ||||
| Fe ii in emission with P-Cygni profiles | ||||
| 1/2 Nov. 2013 | 2 456 598.5 | Fe ii, [Fe ii], and strong hydrogen lines in emission, | late B-typea | 14 |
| P-Cygni profiles | ||||
| He i very weakly in absorption | ||||
Notes.
Reference. (1) Hubble & Sandage (1953); (2) Sharov et al. (1975); (3) Humphreys (1975); (4) Humphreys (1978); (5) Kenyon & Gallagher (1985); (6) Humphreys et al. (1988); (7) Szeifert et al. (1996); (8) Massey et al. (1995); (9) Clark et al. (2012); (10) this paper; (11) Viotti et al. (2006); (12) Humphreys et al. (2014); (13) Viotti et al. (2013); (14) Valeev et al. (2013).
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