scholarly journals The hidden nuclear spectrum of the luminous IRAS source FSC 10214+4724

1994 ◽  
Vol 429 ◽  
pp. L49 ◽  
Author(s):  
Buell T. Jannuzi ◽  
Richard Elston ◽  
Gary D. Schmidt ◽  
Paul S. Smith ◽  
H. S. Stockman
Keyword(s):  
Iras Source

scholarly journals SAO 244567 (HEN1357): A Post-Agb Star which has turned into a Planetary Nebula within the last 20 years

1998 ◽  
Vol 11 (1) ◽  
pp. 358-358
Author(s):  
M. Parthasarathy
Keyword(s):  
Planetary Nebula ◽  
Far Infrared ◽  
Central Star ◽  
Terminal Velocity ◽  
Galactic Latitude ◽  
Iras Source ◽  
High Galactic Latitude ◽  
Alpha Emission ◽  
Early Type Star ◽  
Emission Strength

SAO 244567 (Henl357) (IRAS 17119-5926) is a high galactic latitude (1 = 331°, b = −12°) early type star, originally classified as a B or A type H-alpha emission line star by Henize (1976). It is an IRAS source with far infrared colours similar to planetary nebulae. The IUE ultraviolet spectra obtained during the last eight years show that the central star is rapidly evolving. It is found that the central star of this young PN has faded by a factor of 3 within the last seven eight years. The terminal velocity of the stellar wind has decreased from −3500 km/sec in 1988 to almost zero in 1994. In 1988 the C IV (1550A) line which was a P-Cygni profile with strong absorption component had almost vanished by 1994. The CIII] 1909A emission strength increased markedly within 4 years from 1988 to 1992. The optical spectra obtained since 1990 shows very clearly only the nebular spectrum which is very similar to that of low excitation planetary nebula. The optical spectrum of SAO 244567 obtained in 1971 shows that it was a post-AGB B 1 or B2 supergiant at that time. This result shows that SAO 244567 has turned into a planetary nebula within the last 20 years. Recently Bobrowsky (1994) obtained narrowband optically resolved images in both H-beta and [OIII] 5007A with the HST planetary camera which revealed a well resolved nebula of size 2 seconds of arc. In this paper we discuss the recent new results.

scholarly journals Near-infrared observations of the Z about 2.3 IRAS source FSC 10214 + 4724

1991 ◽  
Vol 381 ◽  
pp. L55 ◽  
Author(s):  
B. T. Soifer ◽  
G. Neugebauer ◽  
J. R. Graham ◽  
K. Matthews ◽  
J. M. Mazzarella ◽  
...  
Keyword(s):  
Near Infrared ◽  
Iras Source ◽  
Infrared Observations

scholarly journals   Andromedae (K3 III):an IRAS source with an unusual ultraviolet spectrum*

1987 ◽  
Vol 224 (1) ◽  
pp. 93-106 ◽  
Author(s):  
P. G. Judge ◽  
C. Jordan ◽  
M. Rowan-Robinson
Keyword(s):  
Ultraviolet Spectrum ◽  
Iras Source

scholarly journals The IUE Ultraviolet Spectrum of PC 11

1993 ◽  
Vol 155 ◽  
pp. 398-398 ◽  
Author(s):  
M. Parthasarathy ◽  
S.R. Pottasch ◽  
J. Clavel
Keyword(s):  
Short Wavelength ◽  
Planetary Nebula ◽  
Significant Variation ◽  
Central Star ◽  
Ultraviolet Spectrum ◽  
Emission Lines ◽  
Symbiotic Star ◽  
Iras Source ◽  
Long Wavelength ◽  
Cold Dust

PC 11 (HD 149427, PK 331-5 1) is classified as a young planetary nebula with strong OIII 4363Å and a Zanstra temperature of TZ = 27000K. It is also classified as (D′ — type) yellow symbiotic star with A — F type companion. It is an IRAS source with detached cold dust with far intrared (IRAS) colours similar to planetary nebulae. The IUE short wavelength (SWP) spectra show emission lines due to OIII] (1661/1666Å). NIII] (1746/1754Å) CIII] (1907/1909Å). The OIII] and NIII] emission lines show significant variation. Variation in the strength of CIII] is not very significant. The strength of OIII] has decreased and NIII] has increased. The long wavelength (LWP) spectrum shows stellar continuum (A-F) and absorption lines due Mg II 2800Å feature. It also show emission lines at 2772Å (?) 3133Å −3140Å (very strong) (OIII, [FeV], 3209Å (He II?) ([FEII]). The variation in the strength of emission line due OIII] and NIII] and the presence of stellar continuum (A-F) suggests that the central star of PC 11 is a binary.

scholarly journals The Chemical Composition of Post AGB Stars

1993 ◽  
Vol 155 ◽  
pp. 352-352
Author(s):  
M. Parthasarathy ◽  
P. Garcia Lario ◽  
S.R. Pottasch
Keyword(s):  
Chemical Composition ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Agb Stars ◽  
Dust Shell ◽  
Signal To Noise ◽  
Iras Source ◽  
Triple Alpha ◽  
Cno Abundances ◽  
Cold Dust

The F-type supergiant HD 56126 (F5I) is an IRAS source with detached cold dust shell with characteristics similar to the dust shells around planetary nebulae. From an analysis of high resolution and high signal to noise ratio spectra metal and CNO abundances have been determined. It is found that in HD 56126 [C/H] =−0.01, [N/H]=+0.17, [O/H] = −0.02, [S/H]=+0.01 and [Fe/H]< −1.0. The C/N/O abundance ratios and CNO abundances relative to Fe of HD 56126 and related post AGB stars suggest that they have on their photospheres the material processed by triple alpha, CN and ON cycles.

scholarly journals Seyfert Activity in Ring Galaxies Due to Galactic Interactions

1999 ◽  
Vol 194 ◽  
pp. 424-425
Author(s):  
Tapan K. Chatterjee
Keyword(s):  
Ring Structure ◽  
Ring Formation ◽  
Optical Counterpart ◽  
Iras Source ◽  
Ring Galaxies

Observations indicate that ring galaxies are more active than spirals (e.g., Ghigo et al., 1983 Appleton and Struck-Marcell, 1987). However, Seyfert activity is noted in only a few ring galaxies, e.g. NGC 985 (de Vaucouleurs & de Vaucouleurs 1975), NGC 1144 = Arp 118 (Huchra et al. 1982), ring galaxy in Sextans-optical counterpart of the IRAS source 09595-0755 (Wakamatus & Nishida). This is indicative of the fact that this type of activity requires favorable circumstances. In this context a previous work on the stellar episode of ring formation, Chatterjee (1984), is extended, including gas and studying the evolution of the ring structure, due to rebounds of the compact elliptical about the plane of the disk.

scholarly journals Hubble Space Telescope Observations of the Luminous IRAS Source FSC 10214+4724: A Gravitationally Lensed Infrared Quasar

1996 ◽  
Vol 461 ◽  
pp. 72 ◽  
Author(s):  
Peter R. Eisenhardt ◽  
Lee Armus ◽  
David W. Hogg ◽  
B. T. Soifer ◽  
G. Neugebauer ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Iras Source ◽  
Space Telescope

scholarly journals High spatial resolution continuum and H-alpha imaging of the high-redshift IRAS source FSC 10214+4724

1992 ◽  
Vol 399 ◽  
pp. L55 ◽  
Author(s):  
B. T. Soifer ◽  
G. Neugebauer ◽  
K. Matthews ◽  
C. Lawrence ◽  
J. Mazzarella
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
High Redshift ◽  
Iras Source

scholarly journals Strange Among the Strange: The B-emission Star γ Cassiopeiæ

2002 ◽  
Vol 187 ◽  
pp. 221-237 ◽  
Author(s):  
P. Harmanec
Keyword(s):  
Unsolved Problem ◽  
Central Star ◽  
Time Variability ◽  
Be Stars ◽  
Iras Source ◽  
B Stars ◽  
X Ray ◽  
Spectroscopic Binary ◽  
Present Understanding

Abstractγ Cas (HD 5394) is an important representative of Be stars, hot B stars exhibiting Balmer and other emission lines in their spectra at certain epochs. Its emission spectrum was observed as early as in 1863 and has undergone spectacular changes since then. γ Cas is also extremely interesting because it qualifies for several phenomenologically defined groups: it is a light and colour variable, long-term radial-velocity variable, X-ray source, IRAS source, rapid line-profile variable, a single-line spectroscopic binary and a central star of a reflection nebula.A critical compilation of the wealth of observational data on the star, with emphasis on its time variability on several time scales, as well as an estimate of the most probable values of all basic physical properties of the object is presented. It is pointed out that in spite of a large quantity of data, systematic and well-calibrated observations are still rather rare. The present understanding of the object is put into perspective of the more general – and as yet unsolved – problem of the formation of Be envelopes.

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