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- ID:
- ivo://CDS.VizieR/J/A+A/655/A46
- Title:
- Simulated IR spectra of PN Hubble 12
- Short Name:
- J/A+A/655/A46
- Date:
- 10 Mar 2022 07:09:39
- Publisher:
- CDS
- Description:
- We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST and CFHT observations of this nebula reveal three pairs of bipolar structures and an arc-shaped filament near the western waist of Hb 12. The existence of nested bipolar lobes together with the presence of H2 knots suggests that these structures originated from several mass-ejection events during the pre-PN phase. To understand the intrinsic structures of Hb 12, a three-dimensional model enabling the visualisation of this PN at various orientations was constructed. The modelling results show that Hb 12 may resemble other nested hourglass nebulae, such as Hen 2-320 and M 2-9, suggesting that this type of PN may be common and the morphologies of PNs are not so diverse as is shown by their visual appearances. The infrared spectra show that this PN has a mixed chemistry. We discuss the possible material that may cause the unidentified infrared emissions. The analyses of the infrared spectra and the spectral energy distribution suggest the existence of a cool companion in the nucleus of this object.
- ID:
- ivo://CDS.VizieR/J/A+AS/127/185
- Title:
- SiO masers in OH/IR stars, proto-PN and PN
- Short Name:
- J/A+AS/127/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for SiO masers towards a sample of 126 objects including OH/IR stars, proto-planetary and planetary nebulae. All objects are classified as oxygen-rich, and most of them are associated with OH or H_2_O masers. SiO masers were found only in variable objects like the OH/IR stars and a few objects classified as proto-planetary nebulae, but with variable central stars that may be part of binary systems. In one object, OH 15.7+0.8, which appears to be varying irregularly and most likely recently left the AGB, an SiO maser was tentatively detected. Thus, we conclude that variability and SiO maser emission are closely linked, and that SiO masers disappear very soon after a star has reached the end of the AGB, when pulsation and mass loss cease.
- ID:
- ivo://CDS.VizieR/III/85
- Title:
- Sixth Catalogue of Galactic Wolf-Rayet Stars
- Short Name:
- III/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This dataset consists of three files which reproduce data from three tables in the reference. The first file is a catalog of 159 Population I Galactic Wolf-Rayet Stars. The catalog includes a cross index between a running entry number, the best known or earliest catalog reference, HD, BD/CPD, CD, and LS. Each star also has a equatorial (1950.0) and galactic positions, precession to 2000.0, spectral type, binary information (if it applies), narrow-band v and b photometry, and reference codes for each of the previous data. The second file is a catalog of 45 Central Stars of Planetary Nebulae of Type [WR], [WR-Of], [O VI], [WC 10] and [WC 11]. The catalog contains a running entry number and identifications for the planetary nebula in which the star is located. Each star also has a equatorial (1950.0) and galactic positions, spectral type, visual magnitude, reference codes for each of the previous data, and an index for additional references which are in the third file.
- ID:
- ivo://CDS.VizieR/J/MNRAS/311/741
- Title:
- SMC emission-line objects
- Short Name:
- J/MNRAS/311/741
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- H{alpha} and [OIII] narrow-band, wide-field (7x7deg^2^), CCD images of the Small Magellanic Cloud were compared, and a catalogue of candidate planetary nebulae and H{alpha} emission-line stars was compiled. The catalogue contains 131 planetary nebulae candidates, 23 of which are already known to be or are probable planetary nebulae or very low excitation objects. Also, 218 emission-line candidates have been identified, with 113 already known. Our catalogue therefore provides a useful supplement to those of Meyssonnier & Azzopardi (1993, Cat. <J/A+AS/102/451>) and Sanduleak, MacConnell & Davis Phillip (1978PASP...90..621S). Further observations are required to confirm the identity of the unknown objects.
- ID:
- ivo://CDS.VizieR/J/PASP/120/380
- Title:
- Spatial orientation of planetary nebulae
- Short Name:
- J/PASP/120/380
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the spatial orientation of a homogeneous sample of 440 elongated Planetary Nebulae (PNe) in order to determine the orientation of their apparent major axis with respect to the Milky Way plane. We present some important geometrical and statistical considerations that have been overlooked by previous works on the subject. The global distribution of galactic position angles (GPA) of PNe is quantitatively not very different from a random distribution of orientations in the Galaxy. Nevertheless, we find that there is at least one region on the sky, toward the Galactic center, where a weak correlation may exist between the orientation of the major axis of some PNe and the Galactic equator, with an excess of axes with GPA~100{deg}. Therefore, we confirm that extrinsic phenomena (i.e., global Galactic magnetic fields, shell compression from motion relative to the Interstellar Medium) do not determine the morphology of PNe on most of the sky, with a possible exception toward the Galactic center.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2963
- Title:
- Spatiokinematics of NGC 1514
- Short Name:
- J/AJ/126/2963
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New spatiokinematic observations were undertaken of the planetary nebula NGC 1514 in the [O III] line at 5007{AA} using an imaging Fabry-Perot spectrometer. Our results show an inner ellipsoidal shell and polar blobs that do not conform to bipolar morphology. It is argued that the nebula is a descendant of a common envelope binary system the periodicity of which is estimated to be about 10 days, with a progenitor mass of 4.5M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/ApJ/771/114
- Title:
- Spectral analysis of 100 evolved PNe from SPM
- Short Name:
- J/ApJ/771/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have selected a group of 100 evolved planetary nebulae (PNe) and study their kinematics based upon spatially-resolved, long-slit, echelle spectroscopy. The data have been drawn from the San Pedro Martir Kinematic Catalogue of PNe (SPM Catalogue). The aim is to characterize in detail the global kinematics of PNe at advanced stages of evolution with the largest sample of homogenous data used to date for this purpose. The results reveal two groups that share kinematics, morphology, and photo-ionization characteristics of the nebular shell and central star luminosities at the different late stages under study. The typical flow velocities we measure are usually larger than seen in earlier evolutionary stages, with the largest velocities occurring in objects with very weak or absent [NII]{lambda}6584 line emission, by all indications the least evolved objects in our sample. The most evolved objects expand more slowly. This apparent deceleration during the final stage of PNe evolution is predicted by hydrodynamical models, but other explanations are also possible. These results provide a template for comparison with the predictions of theoretical models.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A71
- Title:
- Spectra of 14 Magellanic Cloud planetary nebulae
- Short Name:
- J/A+A/642/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained new spectra of fourteen Magellanic Cloud planetary nebulae with the South African Large Telescope to determine heating rates of their central stars and to verify evolutionary models of post asymptotic giant branch stars. We compared new spectra with observations made in previous years. Five planetary nebulae showed an increase of the excitation with time. Four of their central stars exhibit [WC] features in their spectra, including three new detections. This raises the total number of [WC] central stars of PNe in the Magellanic Clouds to ten. We compared determined heating rates of the four [WC] central stars with the He burning post asymptotic giant branch evolutionary tracks and the remaining star with the H-burning tracks. Determined heating rates are consistent with the evolutionary models for both H and He-burning post asymptotic giant branch stars. The central stars of the PNe which show the fastest increase of excitation are also the most luminous in the sample. This indicates that [WC] central stars in the Magellanic Clouds evolve faster than H-burning central stars and originate from more massive progenitors.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A135
- Title:
- Spectra of 78 PN central stars
- Short Name:
- J/A+A/614/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There are more than 3000 known Galactic planetary nebulae (PNe), but only 492 central stars of Galactic planetary nebulae (CSPN) have known spectral types. It is vital to increase this number in order to have reliable statistics, which will lead to an increase of our understanding of these amazing objects. We aim to contribute to the knowledge of central stars of planetary nebulae and stellar evolution. This observational study is based on Gemini Multi-Object Spectrographs (GMOS) and with the Intermediate Dispersion Spectrograph (IDS) at the Isaac Newton Telescope (INT) spectra of 78 CSPN. The objects were selected because they did not have any previous classification, or the present classification is ambiguous. These new high quality spectra allowed us to identify the key stellar lines for determining spectral classification in the Morgan-Keenan (MK) system. We have acquired optical spectra of a large sample of CSPN. From the observed targets, 50 are classified here for the first time while for 28 the existing classifications have been improved. In seven objects we have identified a P-Cygni profile at the HeI lines. Six of these CSPN are late O-type. The vast majority of the stars in the sample exhibit an absorption-type spectrum, and in one case we have found wide emission lines typical of [WR] stars. We give a complementary, and preliminary, classification criterion to obtain the sub-type of the O(H)-type CSPN. Finally, we give a more realistic value of the proportion of CSPN that are rich or poor in hydrogen.
