- ID:
- ivo://CDS.VizieR/J/A+A/643/A110
- Title:
- beta Cas BRITE and SMEI light curves
- Short Name:
- J/A+A/643/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- F type stars are characterised by several physical processes such as different pulsation mechanisms, rotation, convection, diffusion, and magnetic fields. The rapidly rotating delta Scuti star beta Cas can be considered as a benchmark star to study the interaction of several of these effects. We investigate the pulsational and magnetic field properties of beta Cas. We also determine the star's apparent fundamental parameters and chemical abundances. Based on photometric time series obtained from three different space missions (BRITE-Constellation, SMEI, and TESS), we conduct a frequency analysis and investigate the stability of the pulsation amplitudes over four years of observations. We investigate the presence of a magnetic field and its properties using spectropolarimetric observations taken with the Narval instrument by applying the Least Square Deconvolution and Zeeman Doppler Imaging techniques. beta Cas shows only three independent p-mode frequencies down to the few ppm-level; its highest amplitude frequency is suggested to be a n=3, l=2, m=0 mode. Its magnetic field structure is quite complex and almost certainly of a dynamo origin. beta Cas' atmosphere is slightly deficient in iron peak elements and slightly overabundant in C, O, and heavier elements. Atypically for delta Scuti stars, we can only detect three pulsation modes down to exceptionally low noise levels for beta Cas.The star is also one of very few delta Scuti pulsators known to date to show a measurable magnetic field, and the first delta Scuti star with a dynamo magnetic field. These characteristics make beta Cas an interesting target for future studies of dynamo processes in the thin convective envelopes of F-type stars, of the transition region between fossil and dynamo fields, and the interaction between pulsations and magnetic field.
« Previous |
1 - 10 of 11
|
Next »
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/627/A28
- Title:
- beta Pic BRITE, bRing, SMEI light curves
- Short Name:
- J/A+A/627/A28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanet properties crucially depend on the parameters of their host stars: more accurate stellar parameters yield more accurate exoplanet characteristics. When the exoplanet host star shows pulsations, asteroseismology can be used for an improved description of the stellar parameters. We aim to revisit the pulsational properties of {beta} Pic and identify its pulsation modes from normalized amplitudes in five different passbands. We also investigate the potential presence of a magnetic field. We conducted a frequency analysis using three seasons of BRITE-Constellation observations in the two BRITE filters, the about 620-day-long bRing light curve, and the nearly 8-year-long SMEI photometric time series. We calculated normalized amplitudes using all passbands and including previously published values obtained from ASTEP observations. We investigated the magnetic properties of {beta} Pic using spectropolarimetric observations conducted with the HARPSpol instrument. Using 2D rotating models, we fit the normalized amplitudes and frequencies through Monte Carlo Markov chains. We identify 15 pulsation frequencies in the range from 34 to 55d^-1^, where two, F13 at 53.6917d^-1^ and F11 at 50.4921d^-1^, display clear amplitude variability. We use the normalized amplitudes in up to five passbands to identify the modes as three l=1, six l=2, and six l=3 modes. {beta} Pic is shown to be non-magnetic with an upper limit of the possible undetected dipolar field of 300 Gauss. Multiple fits to the frequencies and normalized amplitudes are obtained, including one with a near equator-on inclination for {beta} Pic, which corresponds to our expectations based on the orbital inclination of {beta} Pic b and the orientation of the circumstellar disk. This solution leads to a rotation rate of 27% of the Keplerian breakup velocity, a radius of 1.497+/-0.025R_{sun}_, and a mass of 1.797+/-0.035M_{sun}_. The ~2% errors in radius and mass do not account for uncertainties in the models and a potentially erroneous mode-identification.
- ID:
- ivo://CDS.VizieR/B/corot
- Title:
- CoRoT observation log (N2-4.4)
- Short Name:
- B/corot
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CoRoT, a space astronomy mission, has measured photometric micro-variability of stars from minutes to months (up to 150 days) with a high duty cycle (more than 90%). The mission was led by CNES in association with four French laboratories and 7 participating countries and agencies (Austria, Belgium, Brazil, Germany, Spain, and the ESA Science Programme). The satellite was composed of a PROTEUS platform (the 3rd in the series) and a unique instrument: a stellar rapid photometer. It was launched on December 27th 2006 by a Soyuz Rocket, from Baikonour. The mission has lasted almost 6 years (the nominal 3-year duration and a 3-year extension) and has observed more than 160 000 stars. It stopped sending data on November 2nd 2012. Two regions of the sky were accessible for long period of time: circles of 10 degrees centered on the equator around alpha=06:50 and alpha=18:50. They were called the CoRoT eyes: the "anticenter" and the "center eye" (as they are approximately in these directions). Each pointing covers 1.4x2.8 square degrees within one of those CoRoT eyes. The original scientific objectives were focussed on the study of stellar pulsations (asteroseismology) to probe the internal structure of stars, and the detection of small exoplanets through their "transit" in front of their host star, and the measurement of their size. This lead to introduce two modes of observations, working simultaneously: - The "bright star" mode dedicated to very precise seismology of a small sample of bright and closeby stars - The "faint star" mode, observing a very large number of stars at the same time, to detect transits, which are rare events, as they imply the alignment of the star, the planet and the observer. The large amount of data gathered in this mode turned out to be extremely fruitful for many topics of stellar physics. Beyond these two initial objectives, CoRoT data revealed stellar variability associated with various other phenomena: granulation, rotational modulation by spots associated with magnetic activity, oblateness induced by a nearby companion star, ... The data of this CoRoT CDS archive correspond to the legacy release V4.4 of CoRoT N2 data. A complete description can be found in the "CoRoTN2versions_30sept2014.pdf" document available on the vizier ftp as well as on project websites listed in the "See also" field below. Other archives provide an access to the CoRoT data at different levels, or to complementary catalogues - the CoRoT IAS archive at idoc-corot.ias.u-psud.fr/ and mirrors of this archive at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoT_exo_index.html and at exoplanetarchive.ipac.caltech.edu/applications/ETSS/CoRoT_astero_index.html - archive at https://sipad-corot.cnes.fr/ or at the CoRoT IAS archive, but they require a deep understanding of the instrument and the observation conditions to be scientifically helpful. - Raw data N0 are available upon request at the CoRoT CNES archive. - Complementary data on the CoRoT targets, obtained through ground based complementary observations, can be found in :
- ID:
- ivo://CDS.VizieR/J/A+A/608/A103
- Title:
- 43 Cyg decorrelated 156-day light curve
- Short Name:
- J/A+A/608/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric time series of the gamma Doradus star 43 Cyg obtained with the BRITE-Constellation nano-satellites allow us to study its pulsational properties in detail and to constrain its interior structure. We aim to find a g-mode period spacing pattern that allows us to determine the near-core rotation rate of 43 Cyg and redetermine the star's fundamental atmospheric parameters and chemical composition. We conducted a frequency analysis using the 156-days long data set obtained with the BRITE-Toronto satellite and employed a suite of MESA/GYRE models to derive the mode identification, asymptotic period spacing and near-core rotation rate. We also used high-resolution, high signal-to-noise ratio spectroscopic data obtained at the 1.2m Mercator telescope with the HERMES spectrograph to redetermine the fundamental atmospheric parameters and chemical composition of 43 Cyg using the software Spectroscopy Made Easy (SME). We detected 43 intrinsic pulsation frequencies and identified 18 of them to be part of a period spacing pattern consisting of prograde dipole modes with an asymptotic period spacing of 2970(+700,-570)s. The near-core rotation rate was determined to be 0.56(+0.12,-0.14)c/d. The atmosphere of 43 Cyg shows solar chemical composition at an effective temperature of 7150+/-150K, a logg of 4.2+/-0.6dex and a projected rotational velocity, vsini, of 44+/-4km/s. The morphology of the observed period spacing patterns shows indications of the presence of a significant chemical gradient in the stellar interior.
- ID:
- ivo://archive.stsci.edu/euve
- Title:
- Extreme Ultraviolet Explorer
- Short Name:
- EUVE
- Date:
- 22 Jul 2020 21:28:51
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- Launched in June, 1992, The Extreme Ultraviolet Explorer (EUVE) conducted the first extreme ultraviolet (70-760 Angstroms) survey of the sky and subsequently began a Guest Observer Program of pointed
- ID:
- ivo://archive.stsci.edu/fuse
- Title:
- Far Ultraviolet Spectroscopic Explorer
- Short Name:
- FUSE
- Date:
- 22 Jul 2020 21:29:31
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The Far Ultraviolet Spectroscopic Explorer (FUSE), launched on June 24, 1999, covers the 905-1187 Å spectral region and will obtain high resolution spectra of hot and cool stars, AGNs, supernova remnants, planetary nebulae, solar system objects as well as perform detailed studies of the interstellar medium. FUSE will be able to observe sources 10 000 times fainter than Copernicus, an early FUV mission, and has superior resolving power than the Hopkins Ultraviolet Telescope (HUT) and the Berkeley Spectrograph (BEFS) and the Tübingen Echelle Spectrograph (TUES) of the Orbiting Retrievable Far and Extreme Ultraviolet Spectrometers (ORFEUS). FUSE was planned for a 3 year lifetime with funding for an additional 2 years expected.
- ID:
- ivo://archive.stsci.edu/hst/hsp
- Title:
- High Speed Photometer
- Short Name:
- HST.HSP
- Date:
- 23 Jul 2020 19:49:53
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The High Speed Photometer (HSP) was one of the four original axial instruments on the Hubble Space Telescope (HST). The HSP was designed to make very rapid photometric observations of astrophysical sources in a variety of filters and passbands from the near ultraviolet to the visible. The HSP was removed from HST during the First Servicing Mission in December, 1993.
- ID:
- ivo://archive.stsci.edu/hut
- Title:
- Hopkins Ultraviolet Telescope
- Short Name:
- HUT
- Date:
- 22 Jul 2020 21:30:05
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The Hopkins Ultraviolet Telescope (HUT) was a shuttle-borne instrument used to obtain ultraviolet spectra in the far ultraviolet region of the spectrum. It was part of the ASTRO payload complement of three co-mounted instruments that flew in December 1990 and March 1995 as Space Shuttle missions. More than 650 spectra were obtained of 340 targets. In April, 2013, the HUT data was reprocessed to improve calibration, expand metadata, add new data products, and update file formats. The current cone service uses the metadata from these reprocessed files.
- ID:
- ivo://archive.stsci.edu/k2
- Title:
- Kepler K2 Data Search Catalog
- Short Name:
- K2
- Date:
- 22 Jul 2020 21:33:57
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- Launched in 2009, the Kepler Mission is surveying a region of our galaxy to determine what fraction of stars in our galaxy have planets and measure the size distribution of those exoplanets. Although Kepler completed its primary mission to determine the fraction of stars that have planets in 2013, it is continuing the search, using a more limited survey mode, under the new name K2. The K2 Data Search Service provides the main catalog for all K2 data.
- ID:
- ivo://archive.stsci.edu/kepler_koi
- Title:
- Kepler Objects of Interest (KOI)
- Short Name:
- KOI CS
- Date:
- 12 Feb 2020 19:51:12
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- Launched in 2009, the Kepler Mission is surveying a region of our galaxy to determine what fraction of stars in our galaxy have planets and measure the size distribution of those exoplanets. Although Kepler completed its primary mission to determine the fraction of stars that have planets in 2013, it is continuing the search, using a more limited survey mode, under the new name K2. KOI is the Kepler Objects of Interest catalog listing observed Kepler targets which are flagged as potentially having exoplanets but may be false positives caused by other types of transient detection. This catalog is produced by the Kepler project and brought to MAST via NExScI.