New H-alpha emission stars in the Milky Way.

Stephenson, C. B.; Sanduleak, N.

doi:10.1086/190437

Cited by 120 publications

(89 citation statements)

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“…The absence of spatial variations in the slightly extended two-dimensional spectrum indicates that the illuminated lobes emit probably as a consequence of dust scattering the light coming from the central star. Similar reÑection nebulae have been observed around other prototypical bipolar PPNe, such as M1-92 (Solf 1994 Stephenson & Sanduleak (1977), IRAS 16594[4656 was Ðrst suggested as a possible transition object between the AGB and the PN stage independently by and van der Veen, Habing, & Geballe (1989), based on its IRAS colors, although it was wrongly classiÐed as an O-rich PPN candi-date at that moment because it erroneously appeared to be associated with the O-rich low-resolution spectrometer (LRS) class 74 in the IRAS LRS Catalog (Olnon et al 1986). …”

Section: T He Iso Spectrumsupporting

confidence: 79%

Infrared Space ObservatoryObservations of IRAS 16594−4656: A New Proto–Planetary Nebula with a Strong 21 Micron Dust Feature

García-Lario¹,

Manchado

Ulla

et al. 1999

ApJ

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Based on ISO short-wavelength spectrograph (SWS) ] long-wavelength spectrograph (LWS) observations, IRAS 16594[4656 is identiÐed as a new member of the rare class of C-rich protoÈplanetary nebulae with the 21 km dust feature in emission. In addition, the major polycyclic aromatic hydrocarbon (PAH) emission bands at 3. 3, 6.2, 7.7, 8.6, and 11.3 km are detected, together with unusually strong features at 12.6 and 13.4 km, very rarely observed, attributed to PAH species with a high degree of hydrogenation. The shapes and relative intensities of the various features found are consistent with a mixed population of transient decomposition products of large hydrogenated amorphous carbonaceous (HAC) grains, consisting of fullerenes with di †erent degrees of hydrogenation, which we suggest to be the main carriers of the strong 21 km feature, and a combination of small and large partially dehydrogenated cationic PAH molecules excited by the visible radiation coming from the central star. Additional features corresponding to crystalline silicates (mostly pyroxenes) are also tentatively detected, together with a possible very broad unidentiÐed emission feature centered around 30 km, previously reported as appearing in combination with the 21 km feature in other protoÈplanetary nebulae candidates.

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Section: T He Iso Spectrumsupporting

confidence: 79%

Infrared Space ObservatoryObservations of IRAS 16594−4656: A New Proto–Planetary Nebula with a Strong 21 Micron Dust Feature

García-Lario¹,

Manchado

Ulla

et al. 1999

ApJ

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“…Therefore, we searched again Table 1 of Sanduleak & Stephenson (1972) and found that Stephenson & Sanduleak (1977) and later spectroscopically observed by Downes & Keyes (1988). Its spectrum is described by Van de Steene et al (1996) and Parthasarathy et al (2000).…”

Section: Introductionmentioning

confidence: 95%

Identification of PN G232.0+05.7 as a new halo planetary nebula and of IRAS 19336-0400 as a new type III planetary nebula

Pereira

Miranda

2007

A&A

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Aims. We determined the nature and Peimbert type of two low-excitation planetary nebulae, PNG 232.0+05.7 and IRAS 19336-0400. Methods. We used low resolution optical spectroscopy in the range 3200-9000 Å. Results. We derived line intensities, reddening, physical conditions (electron density and temperature) and ionic and elemental abundances. Based on the abundance analysis and its radial velocity we conclude that PNG 232.0+05.7 is a halo planetary nebulae. This discovery thus adds this object to the sample of ten known halo planetary nebulae. IRAS 19336-0400 is probably a type III planetary nebulae, as strongly suggested by its abundances and high radial velocity, although this conclusion awaits a better estimation of its distance.Key words. planetary nebulae: individual: PN G232.0+05.7 -planetary nebulae: individual: IRAS 19336+0400 IntroductionThe two objects analyzed in this work, PN G232.0+05.7 and IRAS 19336-0400, came to our attention for different reasons. In the case of PN G232.0+05.7 we were looking for whether in Table 1 of Sanduleak & Stephenson (1972) an object classified as a very low-excitation nebula, would have any information about the presence of absorption features in its spectrum. If so, this object could be a good target to be labelled as a "peculiar planetary nebula" as those singled out by Lutz (1977). In her study, she realize that there is a small group of objects in the Catalogue of Planetary Nebulae (Perek & Kohoutek 1967) that appear peculiar because they have nebular emission lines in combination with the absorption spectrum of a cool (spectral type A to K) central star.To illustrate the connection between an object classified as a very low-excitation compact nebula and one that could might be called as "peculiar planetary nebula", according to Lutz (1977), we could mention Hen 3-1312 (=SaSt 2-12, Sanduleak & Stephenson 1972). Pereira (2004) shows that Hen 3-1312 has a continuum spectrum of a F-type star with emission lines. Another example of a very low-excitation compact nebula, but instead, with a continuum of a hot star, is provided by the object Hen 2-138 (=SaSt 2-10, its spectrum is shown in Fig. 1).Since our primary goal is to find an object which presents in its spectrum emission lines in combination with the absorption features of a cool star, we first need to observe spectroscopically a candidate in order to set what kind of very low-excitation compact nebula we are going to investigate. Therefore, we searched again Table 1 of Sanduleak & Stephenson (1972) and found that Stephenson & Sanduleak (1977) and later spectroscopically observed by Downes & Keyes (1988). Its spectrum is described by Van de Steene et al. (1996) and Parthasarathy et al. (2000). They both suggest that IRAS 19336-0400 is a young and low-excitation planetary nebula with a B1 supergiant central star.In this paper we present an abundance analysis of these two low-excitation objects, based on low resolution optical spectroscopy, carried out with the aim of investigating their nature in detail. ...

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“…8 Star 2883 in the catalog of Luminous Stars in the Southern Milky Way (Stephenson & Sanduleak 1971) is also known as CPD −63 • 2495. The use of SS 2883 should be avoided, as this acronym refers to the catalog of emission-line stars by Stephenson & Sanduleak (1977), which contains only 455 stars.…”

Section: Introductionmentioning

confidence: 99%

Astrophysical Parameters of Ls 2883 and Implications for the PSR B1259-63 Gamma-Ray Binary

Negueruela

Ribó

Herrero

et al. 2011

ApJ

123

174

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Only a few binary systems with compact objects display TeV emission. The physical properties of the companion stars represent basic input for understanding the physical mechanisms behind the particle acceleration, emission, and absorption processes in these so-called gamma-ray binaries. Here we present high-resolution and high signalto-noise optical spectra of LS 2883, the Be star forming a gamma-ray binary with the young non-accreting pulsar PSR B1259-63, showing it to rotate faster and be significantly earlier and more luminous than previously thought. Analysis of the interstellar lines suggests that the system is located at the same distance as (and thus is likely a member of) Cen OB1. Taking the distance to the association, d = 2.3 kpc, and a color excess of E(B − V ) = 0.85 for LS 2883 results in M V ≈ −4.4. Because of fast rotation, LS 2883 is oblate (R eq 9.7 R and R pole 8.1 R ) and presents a temperature gradient (T eq ≈ 27,500 K, log g eq = 3.7; T pole ≈ 34,000 K, log g pole = 4.1). If the star did not rotate, it would have parameters corresponding to a late O-type star. We estimate its luminosity at log(L * /L ) 4.79 and its mass at M * ≈ 30 M . The mass function then implies an inclination of the binary system i orb ≈ 23• , slightly smaller than previous estimates. We discuss the implications of these new astrophysical parameters of LS 2883 for the production of high-energy and very high-energy gamma rays in the PSR B1259-63/ LS 2883 gamma-ray binary system. In particular, the stellar properties are very important for prediction of the line-like bulk Comptonization component from the unshocked ultrarelativistic pulsar wind.

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New H-alpha emission stars in the Milky Way.

Cited by 120 publications

References 0 publications

Infrared Space ObservatoryObservations of IRAS 16594−4656: A New Proto–Planetary Nebula with a Strong 21 Micron Dust Feature

Infrared Space ObservatoryObservations of IRAS 16594−4656: A New Proto–Planetary Nebula with a Strong 21 Micron Dust Feature

Identification of PN G232.0+05.7 as a new halo planetary nebula and of IRAS 19336-0400 as a new type III planetary nebula

Astrophysical Parameters of Ls 2883 and Implications for the PSR B1259-63 Gamma-Ray Binary

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