- ID:
- ivo://CDS.VizieR/J/A+A/542/A18
- Title:
- {beta}Pic Harps radial velocity data
- Short Name:
- J/A+A/542/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The {beta} Pictoris system with its debris disk and a massive giant planet orbiting at ~=9AU represents an ideal laboratory for studying giant planet formation and evolution as well as planet-disk interactions. {beta} Pic b can also help in testing brightness-mass relations at young ages. Other planets, yet undetected, may of course be present in the system. We aim at directly constraining the mass of {beta} Pic b and at searching for additional jovian planets on orbits closer than typically 2AU.
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1792. beta Pic HARPS spectrum
- ID:
- ivo://CDS.VizieR/J/A+A/607/A25
- Title:
- beta Pic HARPS spectrum
- Short Name:
- J/A+A/607/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The young planetary system beta Pictoris is surrounded by a circumstellar disk of dust and gas. Because both dust and gas have a lifetime shorter than the system age, they need to be replenished continuously. The gas composition is partly known, but its location and its origin are still a puzzle. The gas source could be the exocomets (or so-called falling and evaporating bodies, FEBs), which are observed as transient features in absorption lines of refractory elements (Mg, Ca, and Fe) when they transit in front of the star at several tens of stellar radii. Nearly 1700 high-resolution spectra of beta Pictoris have been obtained from 2003 to 2015 using the HARPS spectrograph. In these spectra, the circumstellar disk is always detected as a stable component among the numerous variable absorption signatures of transiting exocomets. Summing all the 1700 spectra allowed us to reach a signal-to-noise ratio higher than 1000, which is an unprecedentedly high number for a beta Pictoris spectrum. It revealed many weak Fe I absorption lines of the circumstellar gas in more than ten excited states. These weak lines bring new information on the physical properties of the neutral iron gas in the circumstellar disk. The population of the first excited levels follows a Boltzmann distribution with a slope consistent with a gas temperature of about 1300K; this temperature corresponds to a distance to the star of ~38 R_star_ and implies a turbulence of ksi~0.8km/s.
1793. Beta Pictoris 1994-96
- ID:
- ivo://CDS.VizieR/J/MNRAS/304/733
- Title:
- Beta Pictoris 1994-96
- Short Name:
- J/MNRAS/304/733
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution spectroscopy of the variable CaII H & K absorptions in the star Beta Pictoris. 313 spectra were obtained on 53 nights between 1994 November and 1996 December in order to characterize the lines' behaviour and to test the Falling Evaporating Bodies (FEB) scenario. Near-continuous absorption activity was seen, including blue-shifted features, one of which rivalled the strength of that reported in 1997 June by Crawford et al. (1998MNRAS.294L..31C). Redshifted features at ~5-20km/s were present until the end of 1995 and are evocative of a year-long stream of infalling bodies with typically 4-5 objects in the line of sight. At higher velocities, features were shorter lived and generally broader and shallower. These correlations also apply to blue-shifted features. On 1995 June 9 we detected a probably narrow, short-lived feature at a redshift of ~130km/s. The FEB models predict that the strength of the H line may exceed the K line value as a body tracks across the stellar disc, but we have no convincing observation of this, though we did observe some events where the H & K absorptions evolved differently.
- ID:
- ivo://CDS.VizieR/J/MNRAS/489/574
- Title:
- beta Pictoris 1997 and 1998 spectra
- Short Name:
- J/MNRAS/489/574
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopy with resolution R~33000 of the circumstellar CaII H & K absorptions in the star beta Pictoris during 1997 and 1998. From 1997 April onwards, both lines were observed simultaneously. A total of 688 spectra were obtained on 95 nights in order to characterize the lines' behaviour. Near-continuous Falling Evaporating Body (FEB) variable absorption activity was seen, including additional strong, blue-shifted features besides the one on 1997 June 19-20 already reported by others. Temporal coverage is more even than in the HARPS spectra from 2004-11 that have been analysed for FEB orbital parameters via a model of FEB evaporation. Our observations likely encompass the 1997-98 Hill-sphere transit by beta Pic b, but we have found no clear signature of transiting material. Lower-velocity FEB absorptions tend to be deeper, narrower and longer lived, in confirmation of earlier studies. The ratio of line strengths for one absorption on 1998 November 27 is evocative of the variations expected for a single FEB making a transit perpendicular to the stellar rotation axis. Analysis with the evaporation model produces similar distributions of orbital parameters to those obtained from the HARPS observations, but when the derived orbital parameters are fed into a model based solely on gravitational dynamics of point masses, the predicted FEB accelerations do not agree with observed values. More sophisticated modelling is called for. There is no convincing intrinsic variation in the central circumstellar absorption such as might be expected if an HI ring is responsible for the confinement of circumstellar Ca^+^ ions. Our observations are available electronically for further analysis by others.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A132
- Title:
- beta Pictoris debris disk image
- Short Name:
- J/A+A/646/A132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nearby young star beta Pictoris hosts a rich and complex planetary system, with at least two giant planets and a nearly edge-on debris disk that contains several dynamical subpopulations of planetesimals. While the inner ranges of the debris disk have been studied extensively, less information is known about the outer, fainter parts of the disk. Here we present an analysis of archival FORS V-band imaging data from 2003-2004, which have previously not been explored scientifically because the halo substructure of the bright stellar point spread function is complex. Here we present the deepest imaging yet for the outer range of the beta Pic disk.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A179
- Title:
- beta Pictoris moving group RV of 81 stars
- Short Name:
- J/A+A/642/A179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The {beta} Pictoris moving group is one of the most well-known young associations in the solar neighbourhood and several members are known to host circumstellar discs, planets, and comets. Measuring its age with precision is basic to study several astrophysical processes such as planet formation and disc evolution which are strongly age dependent. We aim to determine a precise and accurate dynamical traceback age for the {beta} Pictoris moving group. Our sample combines the extremely precise Gaia DR2 astrometry with ground-based radial velocities measured in an homogeneous manner. We use an updated version of our algorithm to determine dynamical ages. The new approach takes into account a robust estimate of the spatial and kinematic covariance matrices of the association to improve the sample selection process and to perform the traceback analysis. We estimate a dynamical age of 18.5_-2.4_^+2.0^Myr for the {beta} Pictoris moving group. We investigated the spatial substructure of the association at birth time and we propose the existence of a core of stars more concentrated. We also provide precise radial velocity measurements for 81 members of {beta} Pic, including ten stars with the first determination of their radial velocities. Our dynamical traceback age is three times more precise than previous traceback age estimates and, more important, for the first time, reconciles the traceback age with the most recent estimates of other dynamical, lithium depletion boundary, and isochronal ages. This has been possible thanks to the excellent astrometric and spectroscopic precisions, the homogeneity of our sample, and the detailed analysis of binaries and membership.
1797. beta Pictoris photometry
- ID:
- ivo://CDS.VizieR/J/A+A/648/A15
- Title:
- beta Pictoris photometry
- Short Name:
- J/A+A/648/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric monitoring of beta Pictoris in 1981 showed anomalous fluctuations of up to 4% over several days, consistent with foreground material transiting the stellar disk. The subsequent discovery of the gas giant planet beta Pictoris b and the predicted transit of its Hill sphere to within 0.1 au projected distance of the planet provided an opportunity to search for the transit of a circumplanetary disk in this 21+/-4Myr-old planetary system. Continuous broadband photometric monitoring of beta Pictoris requires ground- based observatories at multiple longitudes to provide redundancy and to provide triggers for rapid spectroscopic followup. These observatories include the dedicated beta Pictoris monitoring observatory bRing at Sutherland and Siding Springs, the ASTEP400 telescope at Concordia, and observations from the space observatories BRITE and Hubble Space Telescope. We search the combined light curves for evidence of short period transient events caused by rings and for longer term photometric variability due to diffuse circumplanetary material. We find no photometric event that matches with the event seen in November 1981, and there is no systematic photometric dimming of the star as a function of the Hill sphere radius. We conclude that the 1981 event was not caused by the transit of a circumplanetary disk around beta Pictoris b. The upper limit on the long term variability of beta Pictoris places an upper limit of 1.8x10^22^g of dust within the Hill sphere. Circumplanetary material is either condensed into a non-transiting disk, is condensed into a disk with moons that has a small obliquity, or is below our detection threshold. This is the first time that a dedicated international campaign has mapped the Hill sphere transit of a gas giant extrasolar planet at 10 au.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/4160
- Title:
- BETA pilot multi-epoch continuum survey
- Short Name:
- J/MNRAS/457/4160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Boolardy Engineering Test Array is a 6x12m dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within an ~30deg^2^ field of view. By cycling the array through 12 interleaved pointing positions and using nine digitally formed beams, we effectively mimic a traditional 1hx108 pointing survey, covering ~150deg^2^ over 711-1015MHz in 12h of observing time. Three such observations were executed over the course of a week. We verify the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1{sigma} thermal noise level of 375{mu}Jy/beam, although the effective noise is a factor of ~3 higher due to residual sidelobe confusion. From this we derive a catalogue of 3722 discrete radio components, using the 35 per cent fractional bandwidth to measure in-band spectral indices for 1037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths.
- ID:
- ivo://nasa.heasarc/askapbeta
- Title:
- BETA Pilot Multi-Epoch Continuum Survey of Spitzer SPT Deep Field
- Short Name:
- ASKAPBETA
- Date:
- 18 Apr 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Boolardy Engineering Test Array (BETA) is a 6 x 12m-dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within an ~30 deg<sup>2</sup> field of view. By cycling the array through 12 interleaved pointing positions and using nine digitally formed beams, the authors have effectively mimicked a traditional 1 hours x 108 pointing survey, covering ~150 deg<sup>2</sup> over 711-1015 MHz in just 12 hours of observing time. Three such observations were executed over the course of a week. The authors verified the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1-sigma thermal noise level of 375 µJy/beam, although the effective noise is a factor of ~3 higher due to residual sidelobe confusion. From this, the authors have derived a catalog of 3,722 discrete radio components, using the 35% fractional bandwidth to measure in-band spectral indices for 1037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope (SPT) Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths. The target field was observed with BETA on three separate occasions as part of the commissioning and verification of the instrument. The telescope delivers 304 MHz of instantaneous bandwidth and for these observations the sky frequency range was 711-1015 MHz, corresponding to a fractional bandwidth of 35%. The data were captured with a frequency resolution of 18.5 kHz, using 16,416 frequency channels across the band. The PYBDSM source finder was used to extract a component catalog from the deep mosaic image formed from a combination of all epochs and sub-bands. Components were fit to islands of emission that had a peak brightness of >5 sigma and an island boundary threshold of >3 sigma, where sigma is the local estimate of the background noise level. Component spectral indices were assigned by matching positions at which spectral indices were successfully fit (Section 4.5 of the reference paper). Following the excision of some spurious detections at the noisy edge of the mosaic, the final catalog contains 3,722 components, 1,037 of which have in-band spectral index measurements. This table was created by the HEASARC in March 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/457/4160">CDS Catalog J/MNRAS/457/4160</a> file table3.dat, the list of source components found in the ASKAP-BETA Survey covering two-thirds of the Spitzer SPT Deep Field. This is a service provided by NASA HEASARC .
1800. Bet Aur light curves
- ID:
- ivo://CDS.VizieR/J/A+A/467/1215
- Title:
- Bet Aur light curves
- Short Name:
- J/A+A/467/1215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the most precise light curve ever obtained of a detached eclipsing binary star and use it investigate the inclusion of non-linear limb darkening laws in light curve models of eclipsing binaries. This light curve, of the bright eclipsing system beta Aurigae, was obtained using the star tracker aboard the WIRE satellite and contains 30000 datapoints with a point-to-point scatter of 0.3mmag. We analyse the WIRE light curve using a version of the EBOP code modified to include non-linear limb darkening laws and to directly incorporate observed times of minimum light and spectroscopic light ratios into the photometric solution as individual observations. We also analyse the dataset with the Wilson-Devinney code to ensure that the two models give consistent results. EBOP is able to provide an excellent fit to the high-precision WIRE data. Whilst the fractional radii of the stars are only defined to a precision of 5% by this light curve, including an accurate published spectroscopic light ratio improves this dramatically to 0.5%. Using non-linear limb darkening improves the quality of the fit significantly compared to the linear law and causes the measured radii to increase by 0.4%. It is possible to derive all of the limb darkening coefficients from the light curve, although they are strongly correlated with each other. The fitted coefficients agree with theoretical predictions to within their fairly large error estimates. We were able to obtain a reasonably good fit to the data using the Wilson- Devinney code, but only using the highest available integration accuracy and by iterating for a long time. Bolometric albedos of 0.6 were found, which are appropriate to convective rather than radiative envelopes. The radii and masses of the components of beta Aurigae are R_A_=2.762+/-0.017R_{sun}_, R_B_=2.568+/-0.017R_{sun}_, M_A_=2.376+/-0.027M_{sun}_ and M_B_=2.291+/-0.027M_{sun}_, where A and B denote the primary and secondary star, respectively. Theoretical stellar evolutionary models can match these parameters for a solar metal abundance and an age of 450 to 500Myr. The Hipparcos trigonometric parallax and an interferometrically-derived orbital parallax give distances to beta Aurigae which are in excellent agreement with each other and with distances derived using surface brightness relations and several sets of empirical and theoretical bolometric corrections.
