scholarly journals 10- m imaging of   Centauri: the Mira variable V42 as the counterpart of the IRAS source?

1995 ◽  
Vol 277 (3) ◽  
pp. 1125-1128 ◽  
Author(s):  
L. Origlia ◽  
F. R. Ferraro ◽  
F. F. Pecci
Keyword(s):  
Iras Source ◽  
Mira Variable

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 Imaging the Surface of a Star: VLBA Monitoring of the SiO Masers around U Herculis

1998 ◽  
Vol 164 ◽  
pp. 245-246
Author(s):  
P. J. Diamond ◽  
A. J. Kemball
Keyword(s):  
Circumstellar Envelope ◽  
Mira Variable

AbstractWe report on 4 epochs of VLBA polarization observations of the 43 GHz, v=1, J=1–0 SiO masers in the circumstellar envelope around the Mira variable U Herculis.

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 Phase-referenced VLBI observations of the OH masers around U Her

1997 ◽  
Vol 180 ◽  
pp. 373-373
Author(s):  
Huib Jan Van Langevelde ◽  
James Brauher ◽  
Philip J. Diamond ◽  
Richard T. Schilizzi
Keyword(s):  
Proper Motion ◽  
Instrumental Effects ◽  
Analysis Software ◽  
Mira Variable ◽  
Vlbi Observations

We have started phase referenced monitoring of the 1667 MHz masers in the Mira variable U Her. Ultimately we hope to determine the annual parallax for this star. Three sets of VLB A observations have been performed so far. The first on July 22 1994, the second on March 6 1995 and a third on August 14 1995. Observations included bright extragalactic sources to calibrate instrumental effects and cycles of calibrator–source–calibrator (≈ 2° away) of typically 6 minutes. Without any special astrometric analysis software we detect the proper motion of U Her with an accuracy of several milli–arcseconds.

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.

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