Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/other/JAD/16.1
- Title:
- GSC 8613-2122 UBVRI and uvby light curves
- Short Name:
- J/other/JAD/16.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a collection of more than 4000 UBVRI and uvby differential photometric measurements of the newly-discovered 12th-magnitude southern Delta Scuti star GSC 08613-02122. The star has a main pulsation period of about 4 hours with an amplitude of 0.05m in the V band. The pulsation amplitude is variable, and the O-C diagram reveals the existence of a long P~29.5-day cycle, which possibly results from the beating of the main pulsation frequency with a nearby frequency.
- ID:
- ivo://CDS.VizieR/J/MNRAS/408/475
- Title:
- HATNet Pleiades Rotation Period Catalogue
- Short Name:
- J/MNRAS/408/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the Hungarian-made Automated Telescope Network (HATNet) survey for transiting exoplanets, we measure photometric rotation periods for 368 Pleiades stars with 0.4~<M~<1.3M_{sun}_. We detect periodic variability for 74 per cent of the cluster members in this mass range that are within our field-of-view, and 93 per cent of the members with 0.7~<M~<1.0M_{sun}_. This increases, by a factor of 5, the number of Pleiades members with measured periods. We compare these data to the rich sample of spectroscopically determined projected equatorial rotation velocities (vsini) available in the literature for this cluster. Included in our sample are 14 newly identified probable cluster members which have proper motions, photometry and rotation periods consistent with membership.
- ID:
- ivo://CDS.VizieR/J/AJ/158/189
- Title:
- HD 126516 radial velocity & photometric observations
- Short Name:
- J/AJ/158/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD 126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary produces detectable eclipses of the primary, and that pair has been given the variable star name V349 Vir. Variations of the center-of-mass velocity of this short-period system have an orbital period of 702.7 days or 1.92 yr and an eccentricity of 0.36. The third star is likely a K or M dwarf. From an analysis of our photometry, we conclude that the primary of HD 126516 is not a {gamma} Dor variable. Comparison with evolutionary tracks indicates that the primary is slightly metal-poor and has an age of 2.5 Gyr. The projected rotational velocity of the primary is very low, just 4 km/s, which is 10 times less than its synchronous rotational velocity. Thus, either that component's rotation is extremely non-synchronous or the inclinations of the rotational and orbital axes are very different, and so the primary has a very large spin-orbit misalignment. Because of the moderate age of the system and the fact that its orbit is already circularized, neither situation is expected theoretically.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1350
- Title:
- Hot variable stars in NGC 330
- Short Name:
- J/AJ/135/1350
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a sample of 150 hot stars in NGC 330, a SMC cluster containing a high fraction of Be stars, we searched for photometric variables using OGLE II data. At least one third of all stars are variable, with 38 being periodic. We found 27 pulsators ({lambda} Eri variables), six eclipsing systems, two bursting sources, and several stars with unusual photometric behavior. Pulsations are present in ~30% of known Be stars, and they are long lived, lasting more than a decade. The strongest pulsators are associated with stars evolved from the main sequence.
- ID:
- ivo://CDS.VizieR/J/AJ/158/16
- Title:
- Identification of RR Lyrae stars from the DES
- Short Name:
- J/AJ/158/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Many studies have shown that RR Lyrae variable stars (RRL) are powerful stellar tracers of Galactic halo structure and satellite galaxies. The Dark Energy Survey (DES), with its deep and wide coverage (g~23.5 mag in a single exposure; over 5000 deg^2^) provides a rich opportunity to search for substructures out to the edge of the Milky Way halo. However, the sparse and unevenly sampled multiband light curves from the DES wide-field survey (a median of four observations in each of grizY over the first three years) pose a challenge for traditional techniques used to detect RRL. We present an empirically motivated and computationally efficient template-fitting method to identify these variable stars using three years of DES data. When tested on DES light curves of previously classified objects in SDSS stripe 82, our algorithm recovers 89% of RRL periods to within 1% of their true value with 85% purity and 76% completeness. Using this method, we identify 5783 RRL candidates, ~28% of which are previously undiscovered. This method will be useful for identifying RRL in other sparse multiband data sets.
- ID:
- ivo://CDS.VizieR/J/A+A/654/A157
- Title:
- 5 ILRTs light curves and spectra
- Short Name:
- J/A+A/654/A157
- Date:
- 07 Mar 2022 07:10:34
- Publisher:
- CDS
- Description:
- We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family of objects similar to the prototypical ILRT SN 2008S. These events have a rise time that is less than 15 days and absolute peak magnitudes of between -11:5 and -14:5mag. Their pseudo-bolometric light curves peak in the range 0.5-9.0*10^40^erg/s and their total radiated energies are on the order of (0.3-3)*10^47^erg. After maximum brightness, the light curves show a monotonic decline or a plateau, resembling those of faint supernovae IIL or IIP, respectively. At late phases, the light curves flatten, roughly following the slope of the ^56^Co decay. If the late-time power source is indeed radioactive decay, these transients produce ^56^Ni masses on the order of 10^-4^ to 10^-3^M_{sun}_. The spectral energy distribution of our ILRT sample, extending from the optical to the mid-infrared (MIR) domain, reveals a clear IR excess soon after explosion and non-negligible MIR emission at very late phases. The spectra show prominent H lines in emission with a typical velocity of a few hundred km/s, along with CaII features. In particular, the [CaII]7291,7324 doublet is visible at all times, which is a characteristic feature for this family of transients. The identified progenitor of SN 2008S, which is luminous in archival Spitzer MIR images, suggests an intermediate-mass precursor star embedded in a dusty cocoon. We propose the explosion of a super-asymptotic giant branch star forming an electron-capture supernova as a plausible explanation for these events.
- ID:
- ivo://CDS.VizieR/J/AJ/144/187
- Title:
- Iris photometry near southern Cepheids. V. AQ Pup
- Short Name:
- J/AJ/144/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photometric UBV survey is presented for 610 stars in a region surrounding the Cepheid AQ Puppis and centered southwest of the variable, based upon photoelectric measures for 14 stars and calibrated iris photometry of photographic plates of the field for 596 stars. An analysis of reddening and distance for program stars indicates that the major dust complex in this direction is ~1.8kpc distant, producing differential extinction described by a ratio of total-to-selective extinction of R=A_V_/E_B-V_=3.10+/-0.20. Zero-age main-sequence fitting for the main group of B-type stars along the line of sight yields a distance of 3.21+/-0.19kpc (V_0_-M_V_=12.53+/-0.13s.e.). The 29.97 Cepheid AQ Pup, of field reddening E_B-V_=0.47+/-0.07 (E_B-V_(B0)=0.51+/-0.07), appears to be associated with B-type stars lying within 5' of it as well as with a sparse group of stars, designated Turner 14, centered south of it at J2000.0=07:58:37, -29:25:00, with a mean reddening of E_B-V_=0.81+/-0.01. AQ Pup has an inferred luminosity as a cluster member of <M_V_>=-5.40+/-0.25 and an evolutionary age of 3x10^7^yr. Its observed rate of period increase of +300.1+/-1.2s/yr is an order of magnitude larger than what is observed for Cepheids of comparable period in the third crossing of the instability strip, and may be indicative of a high rate of mass loss or a putative fifth crossing. Another sparse cluster, designated Turner 13, surrounds the newly recognized 2.59 Cepheid V620 Pup, of space reddening E_B-V_=0.64+/-0.02 (E_B-V_(B0)=0.68+/-0.02), distance 2.88+/-0.11kpc (V_0_-M_V_=12.30+/-0.08s.e.), evolutionary age 10^8^yr, and an inferred luminosity as a likely cluster member of <M_V_>=-2.74+/-0.11. V620 Pup is tentatively identified as a first crosser, pending additional observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/137
- Title:
- ISLAndS project. III. Variable stars
- Short Name:
- J/ApJ/850/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (296), II (251), III (111), XV (117), XVI (8), and XXVIII (87). We also detect a total of 15 Anomalous Cepheids, three eclipsing binaries, and seven field RRL stars compatible with being members of the M31 halo or the Giant Stellar Stream. We derive robust and homogeneous distances to the six galaxies using different methods based on the properties of the RRL stars. Working with the up-to-date set of Period-Wesenheit (I, B-I) relations published by Marconi et al., we obtain distance moduli of {mu}0=[24.49, 24.16, 24.36, 24.42, 23.70, 24.43]mag (respectively), with systematic uncertainties of 0.08mag and statistical uncertainties <0.11mag. We have considered an enlarged sample of 16 M31 satellites with published variability studies, and compared their pulsational observables (e.g., periods and amplitudes) with those of 15 Milky Way satellites for which similar data are available. The properties of the (strictly old) RRL in both satellite systems do not show any significant difference. In particular, we found a strikingly similar correlation between the mean period distribution of the fundamental RRL pulsators (RRab) and the mean metallicities of the galaxies. This indicates that the old RRL progenitors were similar at the early stage in the two environments, suggesting very similar characteristics for the earliest stages of evolution of both satellite systems.
- ID:
- ivo://CDS.VizieR/J/AcA/54/347
- Title:
- IVB mag of LMC ellipsoidal variables
- Short Name:
- J/AcA/54/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the OGLE-II and OGLE-III photometry of red giants in the Large Magellanic Cloud to select and study objects revealing ellipsoidal variability. We detected 1546 candidates for long period ellipsoidal variables and 121 eclipsing binary systems with clear ellipsoidal modulation.