- ID:
- ivo://CDS.VizieR/J/AJ/130/1805
- Title:
- H{alpha} emission stars in NGC 2362
- Short Name:
- J/AJ/130/1805
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An H{alpha} emission survey of the young cluster NGC 2362 resulted in the detection of 130 H{alpha} emission stars in an 11'x11' field approximately centered on the fourth magnitude O9 Ib multiple star {tau} CMa. The survey was carried out using the wide-field grism spectrograph on the University of Hawaii 2.2m telescope and the Gemini Multi-Object Spectrograph (GMOS) on Gemini North. Deep optical VR_C_I_C_ (to V~23.0) and near-infrared (NIR) photometry (JHK) to K~16 were obtained for several fields within the cluster. Spectra covering the 6000-8000{AA} region at a resolution of R~3000 (adequate for the determination of LiI{lambda}6708 line strengths) were also acquired for ~200 pre-main-sequence (PMS) candidates with GMOS.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/129/829
- Title:
- H{alpha} emission stars in NGC 2264
- Short Name:
- J/AJ/129/829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An H{alpha} emission survey of the young cluster NGC 2264 in the Mon OB1 association resulted in the detection of 490 H{alpha} emission stars in a 25'x40' field approximately centered between the O7 V multiple star S Mon and the Cone Nebula. The survey was carried out with the wide-field grism spectrograph (WFGS) on the University of Hawaii 2.2m telescope on Mauna Kea. X-ray observations made with the European Photon Imaging Camera (EPIC) on board the European Space Agency's XMM-Newton satellite observatory will be discussed in a subsequent paper. Optical (BVR_C_I_C_) photometry was obtained for selected fields to supplement similar data from the literature. Spectra covering the 6000-8000{AA} region at a resolution of R~3000 (adequate for the determination of Li I {lambda}6708 line strengths) were obtained for 150 H{alpha} and X-ray emission sources with the Gemini Multi-Object Spectrograph (GMOS).
- ID:
- ivo://CDS.VizieR/II/309
- Title:
- H{alpha} emission stars in the Orion Nebula
- Short Name:
- II/309
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog of 534 H{alpha} emission lines stars in the region of the Orion Nebula (5{deg}x5{deg}) is presented, an the basis of 240 "new" H{alpha} stars found on Tonantzintla spectral plates and previous known H{alpha} emission stars.
- ID:
- ivo://CDS.VizieR/III/177
- Title:
- H-alpha emission stars in the Orion region
- Short Name:
- III/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extensive survey observations were carried out for H-alpha emission stars in six Kiso Areas in the Orion region. The observations were made using mainly the Kiso Schmidt telescope, and partly using the CTIO Curtis Schmidt telescope. Our surveys extends the limiting magnitude to V=17.5 over an area of 150 square degrees, and the total number of detected H-alpha emission stars were 1157. The celestial coordinates and the V magnitudes were measured along with an eye estimation of the H-alpha intensities. The identification from the previous observations were also made. The brightness distribution, which is peaked around V=15, suggests that they are probable candidates of T Tauri-type stars.
- ID:
- ivo://CDS.VizieR/J/AN/324/437
- Title:
- H{alpha} emission stars toward Bulge
- Short Name:
- J/AN/324/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is dealing with the investigation of H-alpha emission stars towards the galactic bulge. In this important region 533 H-alpha emission stars have already been discovered. We add 98 new and 9 possible new (perhaps identical with known objects) H-alpha emission stars found in the objective-prism survey of planetary nebulae and we give the identification charts, the accurate coordinates as well as a rough description. The distribution in l, b of all objects shows the expected concentration towards the galactic equator with the maximum near l=0 and b=0 distorted probably due to strong interstellar extinction.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2739
- Title:
- H-alpha emitting regions in M33
- Short Name:
- J/AJ/110/2739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report finding charts and accurate positions for 432 compact H{alpha} emitting regions in the Local Group Galaxy M33 (NGC 598), in an effort to isolate candidates for an SS433-like stellar system. The objects were extracted from narrowband images, centered in the rest frame H{alpha} ({lambda}6563A) and in the red continuum at 6100A. The atlas is complete down to V=~20, and includes 279 compact H II regions and 153 line emitting point-like sources. The point-like sources undoubtedly include a variety of objects: very small H II regions, early type stars with intense stellar winds, and Wolf-Rayet stars, but should also contain objects with the characteristics of SS433. This extensive survey of compact H{alpha} regions in M33 is a first step towards the identification of peculiar stellar systems like SS433 in external galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/143/61
- Title:
- H{alpha} spectroscopy in IC 1396 HII region
- Short Name:
- J/AJ/143/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have made an extensive survey of emission-line stars in the IC 1396 H II region to investigate the low-mass population of pre-main-sequence (PMS) stars. A total of 639 H{alpha} emission-line stars were detected in an area of 4.2deg^2^ and their i' photometry was measured. Their spatial distribution exhibits several aggregates near the elephant trunk globule (Rim A) and bright-rimmed clouds at the edge of the H II region (Rim B and SFO 37, 38, 39, 41), and near HD206267, which is the main exciting star of the HII region. Based on the extinction estimated from the near-infrared color-color diagram, we have selected PMS star candidates associated with IC1396. The age and mass were derived from the extinction-corrected color-magnitude diagram and theoretical PMS tracks. Most of our PMS candidates have ages of <3Myr and masses of 0.2-0.6M_{sun}_. Although it appears that only a few stars were formed in the last 1Myr in the east region of the exciting star, the age difference among subregions in our surveyed area is not clear from the statistical test. Our results may suggest that massive stars were born after the continuous formation of low-mass stars for 10Myr. The birth of the exciting star could be the late stage of slow but contiguous star formation in the natal molecular cloud. It may have triggered the formation of many low-mass stars at the dense inhomogeneity in and around the HII region by a radiation-driven implosion.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2597
- Title:
- H{alpha} stars and HH objects near BRCs
- Short Name:
- J/AJ/123/2597
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Bright-rimmed clouds (BRCs) found in H II regions are probably sites of triggered star formation due to compression by ionization/shock fronts. Many BRCs harbor IRAS point sources of low dust temperature. They also frequently contain a small cluster of near-IR stars that is elongated along the axis of the BRC. Here we present the results of our H{alpha} grism spectroscopy and narrowband imaging observations of BRCs in search of candidate premain-sequence stars of the T Tauri, Herbig Ae/Be and related types, and Herbig-Haro (HH) objects. We have detected a large number (460) of H{alpha} emission stars down to a limiting magnitude of about R=20 in and around all but two of the 28 BRCs observed. The present study has, for the first time, reached down nearly to the faintest classical T Tauri star population in OB associations. A total of 12 new HH objects have been found.
- ID:
- ivo://CDS.VizieR/J/AJ/135/2323
- Title:
- H{alpha} stars and HH objects near BRCs
- Short Name:
- J/AJ/135/2323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out near-IR/optical observations to examine star formation toward a bright-rimmed cometary globule (BRC37) facing the exciting star(s) of an HII region (IC1396) containing an IRAS source, which is considered to be an intermediate-mass protostar. With slitless spectroscopy we detected ten H{alpha} emission stars around the globule, six of which are near the tip of the globule and are aligned along the direction to the exciting stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/4180
- Title:
- H{alpha} stars in M31 HST photometry
- Short Name:
- J/MNRAS/465/4180
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 224 stars that emit H{alpha} (H{alpha} stars) in the Andromeda galaxy (M31). The stars were selected from ~5000 spectra, collected as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo survey using Keck II/DEIMOS. We used six-filter Hubble Space Telescope photometry from the Panchromatic Hubble Andromeda Treasury survey to classify and investigate the properties of the H{alpha} stars. We identified five distinct categories of H{alpha} star: B-type main-sequence (MS) stars, 'transitioning'-MS (T-MS) stars, red core He burning (RHeB) stars, non-C-rich asymptotic giant branch (AGB) stars, and C-rich AGB stars. We found that ~12 per cent of B-type stars exhibit H{alpha} emission (Be stars). The frequency of Be to all B stars is known to vary with the metallicity of their environment. Comparing this proportion of Be stars with other environments around the Local Group, the result could indicate that M31 is more metal-rich than the Milky Way. We predict that the 17 T-MS H{alpha} stars are Be stars evolving off the MS with fading H{alpha} emission. We separated RHeB from AGB H{alpha} stars. We conclude that the 61 RHeB and AGB stars are likely to be long-period variables. We found that ~14 per cent of C-rich AGB stars (C stars) emit H{alpha}, which is an upper limit for the ratio of C-rich Miras to C stars. This catalogue of H{alpha} stars will be useful to constrain stellar evolutionary models, calibrate distance indicators for intermediate-age populations, and investigate the properties of M31.
