- ID:
- ivo://CDS.VizieR/J/A+A/342/773
- Title:
- Hot carbon stars B-V colour excess
- Short Name:
- J/A+A/342/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A study of 140 hot carbon and related stars. Table 3 contains our hot carbon stars (HC)-classification (see section 2.2 in the paper) for 119 hot carbon stars and their colour excess E(B-V) as determined by the method described in section 2.3. The analogous data for 21 peculiar stars (RCB variables, AC Her [a RV Tau star], V553 Cen [a class II-Cepheid] etc...) can be found in Table 4: most of them have an oxygen-type classification.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/162/188
- Title:
- Hot degenerates in the MCT survey. III.
- Short Name:
- J/AJ/162/188
- Date:
- 21 Mar 2022 00:13:43
- Publisher:
- CDS
- Description:
- We present optical spectra of 144 white dwarfs detected in the Montreal-Cambridge-Tololo colorimetric survey, including 120 DA, 12 DB, 4 DO, 1 DQ, and 7 DC stars. We also perform a model atmosphere analysis of all objects in our sample using the so-called spectroscopic technique, or the photometric technique in the case of DC white dwarfs. The main objective of this paper is to contribute to the ongoing effort of confirming spectroscopically all white dwarf candidates in the Gaia survey, in particular in the southern hemisphere. All our spectra are made available in the Montreal White Dwarf Database.
- ID:
- ivo://CDS.VizieR/J/ApJ/614/671
- Title:
- Hot, dusty ultraluminous galaxies at z~2
- Short Name:
- J/ApJ/614/671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report spectroscopic redshifts for 18 {mu}Jy radio galaxies at a mean redshift of z=2.2 that are faint at both submillimeter and optical wavelengths. While the radio fluxes of these galaxies could indicate far-IR luminosities comparable to high-redshift submillimeter-selected galaxies (>~10^12^L{Sun}), none are detected in the submillimeter.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A136
- Title:
- Hot HB stars in {omega} Cen
- Short Name:
- J/A+A/526/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UV observations of some massive globular clusters have revealed a significant population of stars hotter and fainter than the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C and N enrichment cannot be verified. We compare the observed effective temperatures, surface gravities, helium abundances, and carbon line strengths (where detectable) of our targets stars with the predictions of the two aforementioned scenarios.
- ID:
- ivo://CDS.VizieR/J/ApJ/532/308
- Title:
- Hot Horizontal Branch Stars in the Core of M32
- Short Name:
- J/ApJ/532/308
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the STIS near-UV photometry for the hot stars in the core of M32. The catalog includes 8021 stars, and gives position in the STIS image, magnitude, error, region of the image, RA (J2000), and Dec (J2000). The photometry was performed in six distinct regions of the image because of changes in the point spread function across the image. Note that the relative astrometry is quite accurate (tenths of a 0.025 arcsec STIS pixel), but the absolute astrometry is subject to a 1-2 arcsec uncertainty (associated with the position of the guide stars). Three stars were marked with a footnote in the published catalog, because they are associated with planetary nebulae in our field; they are at the following positions (x,y): (354.949, 821.325), (717.148, 669.210), and (994.924, 355.956).
- ID:
- ivo://CDS.VizieR/J/ApJ/788/39
- Title:
- Hot Jupiter exoplanets host stars EW and abundances
- Short Name:
- J/ApJ/788/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot Jupiters, the C/O ratio affects the partitioning of carbon in the major observable molecules, making these elements diagnostic of temperature structure and composition. Here we present measurements of carbon and oxygen abundances in 16 stars that host transiting hot Jupiter exoplanets, and we compare our C/O ratios to those measured in larger samples of host stars, as well as those estimated for the corresponding exoplanet atmospheres. With standard stellar abundance analysis we derive stellar parameters as well as [C/H] and [O/H] from multiple abundance indicators, including synthesis fitting of the [O I] {lambda}6300 line and non-LTE corrections for the O I triplet. Our results, in agreement with recent suggestions, indicate that previously measured exoplanet host star C/O ratios may have been overestimated. The mean transiting exoplanet host star C/O ratio from this sample is 0.54 (C/O_{sun}_=0.54), versus previously measured C/O_host star_ means of ~0.65-0.75. We also observe the increase in C/O with [Fe/H] expected for all stars based on Galactic chemical evolution; a linear fit to our results falls slightly below that of other exoplanet host star studies but has a similar slope. Though the C/O ratios of even the most-observed exoplanets are still uncertain, the more precise abundance analysis possible right now for their host stars can help constrain these planets' formation environments and current compositions.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A81
- Title:
- 15 hot Jupiter exoplanets light curves
- Short Name:
- J/A+A/622/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transit events of extrasolar planets offer a wealth of information for planetary characterization. However, for many known targets, the uncertainty of their predicted transit windows prohibits an accurate scheduling of follow-up observations. In this work, we refine the ephemerides of 21 hot Jupiter exoplanets with the largest timing uncertainties. We collected 120 professional and amateur transit light curves of the targets of interest, observed with a range of telescopes of 0.3m-2.2m, and analyzed them along with the timing information of the planets discovery papers. In the case of WASP-117b, we measured a timing deviation compared to the known ephemeris of about 3.5h, and for HAT-P-29b and HAT-P-31b the deviation amounted to about 2h and more. For all targets, the new ephemeris predicts transit timings with uncertainties of less than 6-min in the year 2018 and less than 13-min until 2025. Thus, our results allow for an accurate scheduling of follow-up observations in the next decade.
- ID:
- ivo://CDS.VizieR/J/AJ/131/866
- Title:
- Hot populations in M87 globular clusters
- Short Name:
- J/AJ/131/866
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To explore the production of UV-bright stars in old, metal-rich populations like those in elliptical galaxies, we have obtained Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph far- and near-UV photometry of globular clusters (GCs) in four fields in the giant elliptical (gE) galaxy M87. To a limit of m_FUV_~25 we detect a total of 66 GCs in common with the deep HST optical-band study of Kundu et al. (1999, Cat. <J/ApJ/513/733>).
- ID:
- ivo://CDS.VizieR/J/A+A/506/1055
- Title:
- Hot stars emitting in X-ray. I.
- Short Name:
- J/A+A/506/1055
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following the advent of increasingly sensitive X-ray observatories, deep observations of early-type stars became possible. However, the results for only a few objects or clusters have until now been reported and there has been no large survey comparable to that based upon the ROSAT All-Sky Survey (RASS). A limited survey of X-ray sources, consisting of all public XMM observations (2XMMi) and slew survey data (XMMSL1), is now available. The X-ray counterparts to hot, massive stars have been searched for in these catalogs. About 300 OB stars were detected with XMM. Half of them were bright enough for a spectral analysis to be possible, and we make available the detailed spectral properties that were derived. The X-ray spectra of O stars are represented well by low (<1keV) temperature components and seem to indicate that an absorption column is present in addition to the interstellar contribution. The X-ray fluxes are well correlated with the bolometric fluxes, with a scatter comparable to that of the RASS studies and thus larger than found previously with XMM for some individual clusters. These results contrast with those of B stars that exhibit a large scatter in the L_X-L_BOL relation, no additional absorption being found, and the fits indicate a plasma at higher temperatures. Variability (either within one exposure or between multiple exposures) was also investigated whenever possible: short-term variations are far more rare than long-term ones (the former affects a few percent of the sample, while the latter concerns between one third and two thirds of the sources).
- ID:
- ivo://CDS.VizieR/J/MNRAS/425/355
- Title:
- Hot stars in LMC UKST H{alpha} survey
- Short Name:
- J/MNRAS/425/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new, accurate positions, spectral classifications, radial and rotational velocities, H{alpha} fluxes, equivalent widths and B, V, I, R magnitudes for 579 hot emission-line stars (classes B0-F9) in the Large Magellanic Cloud (LMC) which include 469 new discoveries. Candidate emission-line stars were discovered using a deep, high-resolution H{alpha} map of the central 25 degree^2^ of the LMC obtained by median stacking a dozen 2h H{alpha} exposures taken with the UK Schmidt Telescope (UKST). Spectroscopic follow-up observations on the Anglo-Australian Telescope, the UKST, the Very Large Telescope, the South African Astronomical Observatory 1.9m and the 2.3-m telescope at Siding Spring Observatory have established the identity of these faint sources down to magnitude R_equiv_~23 for H{alpha} (4.5x10^-17^ergs/cm^2^/s/{AA}).