Photometric variability and spectral features of the protoplanetary nebula LSII + 34° 26 = V1853 Cyg

Архипова, В. П.; Иконникова, Н. П.; Noskova, R. I.; Комиссарова, Г. В.; Клочкова, В. Г.; Есипов, В. Ф.

doi:10.1134/1.1415861

Cited by 27 publications

(34 citation statements)

References 5 publications

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“…IRAS 20462+3416.-Our H profile is different from that previously reported by Smith & Lambert (1994) and García-Lario et al (1997b) in particular, the blueshifted absorption component of the P Cygni profile is less pronounced in our observations. These authors already noticed strong changes in the profile of H and other lines in a time scale of days, which are interpreted in terms of mass-loss episodes (see also Arkhipova et al 2001a). We confirm such changes in some recombination lines, for example, we detect the He i k6678 line in absorption; however, this line has had a remarkable P Cygni profile in the past.…”

Section: Variability Of the H Profilesupporting

confidence: 66%

Echelle Long‐Slit Optical Spectroscopy of Evolved Stars

Contreras

Sahai²,

Paz

et al. 2008

Astrophysical Journal Supplement Series, The

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We present echelle long-slit optical spectra of a sample of objects evolving off the asymptotic giant branch (AGB), most of them in the preplanetary nebula ( PPN ) phase, obtained with the ESI and MIKE spectrographs at the 10 m Keck II and 6.5 m Magellan-I telescopes, respectively. The total wavelength range covered with ESI (MIKE) is $3900Y10900 8 ($3600Y7200 8). In this paper, we focus our analysis mainly on the H profiles. Prominent H emission is detected in half of the objects, most of which show broad H wings (with total widths of up to $4000 km s À1 ). In the majority of the H -emission sources, fast, post-AGB winds are revealed by P-Cygni profiles. In $37% of the objects H is observed in absorption. In almost all cases, the absorption profile is partially filled with emission, leading to complex, structured profiles that are interpreted as an indication of incipient post-AGB mass loss. The rest of the objects ($13%) are H nondetections. We investigate correlations between the H profile and different stellar and envelope parameters. All sources in which H is seen mainly in absorption have F-G type central stars, whereas sources with intense H emission span a larger range of spectral types from O to G, with a relative maximum around B, and also including very late C types. Shocks may be an important excitation/ionization agent of the close stellar surroundings for objects with late type central stars. Sources with pure emission or P Cygni H profiles have larger J À K color excess than objects with H mainly in absorption, which suggests the presence of warm dust near the star in the former. The two classes of profile sources also segregate in the IRAS color-color diagram in a way that intense H -emitters have dust grains with a larger range of temperatures. Spectral classification of the central stars in our sample is presented. For a subsample (13 objects), the stellar luminosity has been derived from the analysis of the O i 7771Y7775 8 infrared triplet. The location in the HR diagram of most of these targets, which represent $30% of the whole sample, is consistent with relatively high final (and, presumably, initial) masses in the range M f $ 0:6 Y0:9 M (M i $ 3Y 8 M ).

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Section: Variability Of the H Profilesupporting

confidence: 66%

Echelle Long‐Slit Optical Spectroscopy of Evolved Stars

Contreras

Sahai²,

Paz

et al. 2008

Astrophysical Journal Supplement Series, The

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“…This high galactic latitude (b = +20) post-AGB star (SAO 85766, HD 341617) appears to have evolved rapidly, from a spectral type of A5 in the 1924 HDE catalogue to B1-1.5 based on a 1995 spectrum (Arkhipova et al 1999). The evolution may be even more dramatic, as Parthasarathy et al (2000a) point out that the spectral type was still consistent with A5I in 1973 UV observations, but had become B1I in their 1993 high resolution spectroscopy.…”

Section: Iras 18062+2410mentioning

confidence: 98%

Imaging the transition between pre-planetary and planetary nebulae: integral field spectroscopy of hot post-AGB stars with NIFS

Gledhill

Forde

2014

Monthly Notices of the Royal Astronomical Society

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We present 2-2.4 µm integral field spectroscopy of a sample of hot post-AGB stars with early-B spectral types, using the NIFS instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary nebulae (PNe). We use molecular hydrogen emission lines together with hydrogen and helium recombination lines to explore the distribution of molecular and atomic gas and the extent of the developing ionized region. We see a range of evolutionary stages: IRAS 18062+2410 and IRAS 18379-1707 have recently developed compact and unresolved regions of photoionized H within axisymmetric molecular envelopes, with the former object increasing its Brγ flux by a factor of 5.3 in 14 years; IRAS 22023+5249 and IRAS 20462+3416 have extended Brγ nebulae and in the latter object only weak H 2 emission remains; IRAS 19336-0400 is at a more advanced stage of PN formation where H 2 is mostly dissociated and we see structure in both the H and He recombination line nebulae. IRAS 19200+3457 is the only object not to show the He I line at 2.058 µm and is probably the least evolved object in our sample; the H 2 emission forms a ring around the star and we suggest that this object may be a rare example of a "round" pre-PN in transition to a "round" PN.

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“…A multiwavelength study by García-Lario et al (1997) confirmed that the central star is surrounded by a very low excitation and compact nebula (Ueta et al 2000). The presence of P-Cygni profiles indicate ongoing post-AGB mass-loss (Garcia-Lario et al 1997, Arkhipova et al 2001b. Like Hen 1357 and SAO 85766, LS II +34 26 seems to be another rapidly evolving hot post-AGB star.…”

Section: Ls II +34 26 and Ls Iv -12 111mentioning

confidence: 81%

“…Such nebular emission lines seems to absent in the spectrum of LS II + 34 26 obtained by Turner & Drilling in 1977. Differences in the spectrograms obtained by Turner &Drilling in 1977 and1981 and the recent spectra of LS II +34 26 (Parthasarathy 1994, Garcia-Lario et al 1997, Arkhipova et al 2001b) suggest that it is rapidly evolving into the PN stage. A multiwavelength study by García-Lario et al (1997) confirmed that the central star is surrounded by a very low excitation and compact nebula (Ueta et al 2000).…”

Section: Ls II +34 26 and Ls Iv -12 111mentioning

confidence: 99%

“…Like Hen 1357 and SAO 85766, LS II +34 26 seems to be another rapidly evolving hot post-AGB star. Recently Arkhipova et al (2001b) made photometric and spectroscopic observations of LSII +34 26 and found rapid irregular low amplitude light variations similar to that of SAO 85766 (Arkhipova et al 1999(Arkhipova et al , 2001a.…”

Section: Ls II +34 26 and Ls Iv -12 111mentioning

confidence: 99%

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