Mariangela Bonavita | University of Edinburgh (original) (raw)
Papers by Mariangela Bonavita
Proceedings of the International Astronomical Union, 2011
EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high c... more EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high contrast imager based on a high performing extreme adaptive optics system, a diffraction suppression module, and two scientific instruments: an Integral Field Spectrograph (IFS) for the near infrared (0.95-1.65 μm), and a differential polarization imager (E-POL). Both these instruments should allow imaging and characterization of planets shining in reflected light, possibly down to Earth-size. A few high interesting science cases are presented.
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar... more We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ~3 M_sun and low-mass stars at ~0.2 M_sun. We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ~2 M_Jup. The inferred multiplicity frequency within our sensitivity limits between ~10-1500 AU is 26.3(+6.6/-4.9)%. Applying a completeness correction, 62(+/-14)% of all Taurus stars between 0.7 and 1.4 M_sun appear to be multiple. Higher order multiples were found in 1.8(+4.2/-1.5)% of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ~3.5-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ~2 Myr and ~20 Myr, respectively.
We present the intrinsic radial velocity limits obtained from two different asteroseismological c... more We present the intrinsic radial velocity limits obtained from two different asteroseismological campaigns performed with SARG, the high resolution spectrograph of the TNG (Telescopio Nazionale Galileo). The nightly averages show rms dispersion of just 0.2 m/s over one week. This allows us to exclude short period planets of a few Earth masses around these stars.
High contrast imaging appears to be not only the most promising technique to explore the outer re... more High contrast imaging appears to be not only the most promising technique to explore the outer regions of extrasolar planetary systems, giving us a view of a complementary separation domain, but will also give us information on their atmospheres. The possibility of coupling an integral field spectrograph to a module for extreme adaptive optics and a 8m class telescope is
Although very successful (more than 350 planets discovered up to now) indirect methods for extras... more Although very successful (more than 350 planets discovered up to now) indirect methods for extrasolar planet detection (radial velocity, transits) are sensitive to planets quite close to their hosts. Moreover, accurate studies of planet characteristics are feasible only for a subset of object which are strongly irradiated. Standing at this point, any information about the exoplanets in wide orbits (more than 5-10 AU) is missing. High contrast imaging could be the key to open us a door to an unexplored region of star planet separation and to shed light on these unknown far away worlds. But it's not just a matter of detections. In fact coupling integral field spectrographs to extreme adaptive optic modules at the focus of 8m class telescopes (SPHERE for VLT and GPI for South Gemini), and in the future to ELTs (EPICS), would allow us to perform a first order characterization of the exoplanets themselves. Here we present the potential of the high contrast imaging technique, comparin...
Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are abo... more Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a small number of rocky planets. EPICS is a proposed instrument for the European ELT, dedicated to the detection and characterization of Exoplanets by direct imaging, spectroscopy and polarimetry. ESO completed a phase-A study for EPICS with a large European consortium which - by simulations and demonstration experiments - investigated state-of-the-art diffraction and speckle suppression techniques to deliver highest contrasts. This contribution presents the instrument concept and analysis as well as its main innovations and science capabilities. In particular we'll in...
The Astrophysical Journal, 2015
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar... more We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and substellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ∼3 M ⊙ and low-mass stars at ∼0.2 M ⊙ . We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ∼2 M Jup . The inferred multiplicity frequency within our sensitivity limits between ∼10-1500 AU is 26.3 +6.6 −4.9 %. Applying a completeness correction, 62%±14% of all Taurus stars between 0.7 and 1.4 M ⊙ appear to be multiple. Higher order multiples were found in 1.8 +4.2 −1.5 % of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ∼3.5-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ∼2 Myr and ∼20 Myr, respectively.
Proceedings of the International Astronomical Union, 2013
ABSTRACT Several tools have been developed in the past few years for the statistical analysis of ... more ABSTRACT Several tools have been developed in the past few years for the statistical analysis of the exoplanet search surveys, mostly using a combination of Monte-Carlo simulations or a Bayesian approach.Here we present the Quick-MESS, a grid-based, non-Monte Carlo tool aimed to perform statistical analyses on results from and help with the planning of direct imaging surveys. Quick-MESS uses the (expected) contrast curves for direct imaging surveys to assess for each target the probability that a planet of a given mass and semi-major axis can be detected. By using a grid-based approach Quick-MESS is typically more than an order of magnitude faster than tools based on Monte-Carlo sampling of the planet distribution. In addition, Quick-MESS is extremely flexible, enabling the study of a large range of parameter space for the mass and semi-major axes distributions without the need of re-simulating the planet distribution. In order to show examples of the capabilities of the Quick-MESS, we present the analysis of the Gemini Deep Planet Survey and the predictions for upcoming surveys with extreme-AO instruments.
Proceedings of the International Astronomical Union, 2010
EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high c... more EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high contrast imager based on a high performing extreme adaptive optics system, a diffraction suppression module, and two scientific instruments: an Integral Field Spectrograph (IFS) for the near infrared (0.95-1.65 mum), and a differential polarization imager (E-POL). Both these instruments should allow imaging and characterization
Astrophysics and Space Science Library, 2010
The Astrophysical Journal, 2014
Even though only a handful of sub-stellar companions have been found via direct imaging, each of ... more Even though only a handful of sub-stellar companions have been found via direct imaging, each of these discoveries has had a tremendous impact on our understanding of the star formation process and the physics of cool atmospheres. Young stars are prime targets for direct imaging searches for planets and brown dwarfs, due to the favorable brightness contrast expected at such ages and also because it is often possible to derive relatively good age estimates for these primaries. Here we present the direct imaging discovery of HD 284149 b, a 18 − 50 M Jup companion at a projected separation of 400 AU from a young (25 +25 10 Myr) F8 star, with which it shares common proper motion
EAS Publications Series, 2010
The available results of deep imaging searches for planetary companions around nearby stars provi... more The available results of deep imaging searches for planetary companions around nearby stars provide us useful constraints on the frequencies of giant planets in very wide orbits. Here we present some preliminary results of the Monte Carlo simulation which compare the published detection limits with the generated planetary masses and orbital parameters. This allow us to consider the impications of
ESO Astrophysics Symposia, 2008
We present the status of the radial velocity planet search ongoing at TNG. We are observing about... more We present the status of the radial velocity planet search ongoing at TNG. We are observing about 50 wide binaries with similar components, searching for planets and abundance anomalies caused by the ingestion of metal-rich planetary material. A by-product of our project is the detection of several new spectroscopic binaries. No clear planet detection emerged up to now. Evaluation of the statistical significance in terms of frequency of planets in binaries is in progress. The abundance analysis of half of the sample revealed no pair with large difference.
Ground-based and Airborne Instrumentation for Astronomy III, 2010
The SPHERE is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the ... more The SPHERE is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the vicinity of bright stars and to characterize them through spectroscopic and polarimetric observations. It is a complete system with a core made of an extreme-Adaptive Optics (AO) wavefront correction, a pupil tracker and diffraction suppression through a variety of coronagraphs. At its back
Proceedings of the International Astronomical Union, 2011
EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high c... more EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high contrast imager based on a high performing extreme adaptive optics system, a diffraction suppression module, and two scientific instruments: an Integral Field Spectrograph (IFS) for the near infrared (0.95-1.65 μm), and a differential polarization imager (E-POL). Both these instruments should allow imaging and characterization of planets shining in reflected light, possibly down to Earth-size. A few high interesting science cases are presented.
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar... more We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ~3 M_sun and low-mass stars at ~0.2 M_sun. We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ~2 M_Jup. The inferred multiplicity frequency within our sensitivity limits between ~10-1500 AU is 26.3(+6.6/-4.9)%. Applying a completeness correction, 62(+/-14)% of all Taurus stars between 0.7 and 1.4 M_sun appear to be multiple. Higher order multiples were found in 1.8(+4.2/-1.5)% of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ~3.5-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ~2 Myr and ~20 Myr, respectively.
We present the intrinsic radial velocity limits obtained from two different asteroseismological c... more We present the intrinsic radial velocity limits obtained from two different asteroseismological campaigns performed with SARG, the high resolution spectrograph of the TNG (Telescopio Nazionale Galileo). The nightly averages show rms dispersion of just 0.2 m/s over one week. This allows us to exclude short period planets of a few Earth masses around these stars.
High contrast imaging appears to be not only the most promising technique to explore the outer re... more High contrast imaging appears to be not only the most promising technique to explore the outer regions of extrasolar planetary systems, giving us a view of a complementary separation domain, but will also give us information on their atmospheres. The possibility of coupling an integral field spectrograph to a module for extreme adaptive optics and a 8m class telescope is
Although very successful (more than 350 planets discovered up to now) indirect methods for extras... more Although very successful (more than 350 planets discovered up to now) indirect methods for extrasolar planet detection (radial velocity, transits) are sensitive to planets quite close to their hosts. Moreover, accurate studies of planet characteristics are feasible only for a subset of object which are strongly irradiated. Standing at this point, any information about the exoplanets in wide orbits (more than 5-10 AU) is missing. High contrast imaging could be the key to open us a door to an unexplored region of star planet separation and to shed light on these unknown far away worlds. But it's not just a matter of detections. In fact coupling integral field spectrographs to extreme adaptive optic modules at the focus of 8m class telescopes (SPHERE for VLT and GPI for South Gemini), and in the future to ELTs (EPICS), would allow us to perform a first order characterization of the exoplanets themselves. Here we present the potential of the high contrast imaging technique, comparin...
Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are abo... more Presently, dedicated instruments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a small number of rocky planets. EPICS is a proposed instrument for the European ELT, dedicated to the detection and characterization of Exoplanets by direct imaging, spectroscopy and polarimetry. ESO completed a phase-A study for EPICS with a large European consortium which - by simulations and demonstration experiments - investigated state-of-the-art diffraction and speckle suppression techniques to deliver highest contrasts. This contribution presents the instrument concept and analysis as well as its main innovations and science capabilities. In particular we'll in...
The Astrophysical Journal, 2015
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar... more We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and substellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive Taurus members at ∼3 M ⊙ and low-mass stars at ∼0.2 M ⊙ . We detected 74 companion candidates, 34 of these reported for the first time. Twenty-five companions are likely physically bound, partly confirmed by follow-up observations. Four candidate companions are likely unrelated field stars. Assuming physical association with their host star, estimated companion masses are as low as ∼2 M Jup . The inferred multiplicity frequency within our sensitivity limits between ∼10-1500 AU is 26.3 +6.6 −4.9 %. Applying a completeness correction, 62%±14% of all Taurus stars between 0.7 and 1.4 M ⊙ appear to be multiple. Higher order multiples were found in 1.8 +4.2 −1.5 % of the cases, in agreement with previous observations of the field. We estimate a sub-stellar companion frequency of ∼3.5-8.8% within our sensitivity limits from the discovery of two likely bound and three other tentative very low-mass companions. This frequency appears to be in agreement with what is expected from the tail of the stellar companion mass ratio distribution, suggesting that stellar and brown dwarf companions share the same dominant formation mechanism. Further, we find evidence for possible evolution of binary parameters between two identified sub-populations in Taurus with ages of ∼2 Myr and ∼20 Myr, respectively.
Proceedings of the International Astronomical Union, 2013
ABSTRACT Several tools have been developed in the past few years for the statistical analysis of ... more ABSTRACT Several tools have been developed in the past few years for the statistical analysis of the exoplanet search surveys, mostly using a combination of Monte-Carlo simulations or a Bayesian approach.Here we present the Quick-MESS, a grid-based, non-Monte Carlo tool aimed to perform statistical analyses on results from and help with the planning of direct imaging surveys. Quick-MESS uses the (expected) contrast curves for direct imaging surveys to assess for each target the probability that a planet of a given mass and semi-major axis can be detected. By using a grid-based approach Quick-MESS is typically more than an order of magnitude faster than tools based on Monte-Carlo sampling of the planet distribution. In addition, Quick-MESS is extremely flexible, enabling the study of a large range of parameter space for the mass and semi-major axes distributions without the need of re-simulating the planet distribution. In order to show examples of the capabilities of the Quick-MESS, we present the analysis of the Gemini Deep Planet Survey and the predictions for upcoming surveys with extreme-AO instruments.
Proceedings of the International Astronomical Union, 2010
EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high c... more EPICS is the proposed planet finder for the European Extremely Large Telescope. EPICS is a high contrast imager based on a high performing extreme adaptive optics system, a diffraction suppression module, and two scientific instruments: an Integral Field Spectrograph (IFS) for the near infrared (0.95-1.65 mum), and a differential polarization imager (E-POL). Both these instruments should allow imaging and characterization
Astrophysics and Space Science Library, 2010
The Astrophysical Journal, 2014
Even though only a handful of sub-stellar companions have been found via direct imaging, each of ... more Even though only a handful of sub-stellar companions have been found via direct imaging, each of these discoveries has had a tremendous impact on our understanding of the star formation process and the physics of cool atmospheres. Young stars are prime targets for direct imaging searches for planets and brown dwarfs, due to the favorable brightness contrast expected at such ages and also because it is often possible to derive relatively good age estimates for these primaries. Here we present the direct imaging discovery of HD 284149 b, a 18 − 50 M Jup companion at a projected separation of 400 AU from a young (25 +25 10 Myr) F8 star, with which it shares common proper motion
EAS Publications Series, 2010
The available results of deep imaging searches for planetary companions around nearby stars provi... more The available results of deep imaging searches for planetary companions around nearby stars provide us useful constraints on the frequencies of giant planets in very wide orbits. Here we present some preliminary results of the Monte Carlo simulation which compare the published detection limits with the generated planetary masses and orbital parameters. This allow us to consider the impications of
ESO Astrophysics Symposia, 2008
We present the status of the radial velocity planet search ongoing at TNG. We are observing about... more We present the status of the radial velocity planet search ongoing at TNG. We are observing about 50 wide binaries with similar components, searching for planets and abundance anomalies caused by the ingestion of metal-rich planetary material. A by-product of our project is the detection of several new spectroscopic binaries. No clear planet detection emerged up to now. Evaluation of the statistical significance in terms of frequency of planets in binaries is in progress. The abundance analysis of half of the sample revealed no pair with large difference.
Ground-based and Airborne Instrumentation for Astronomy III, 2010
The SPHERE is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the ... more The SPHERE is an exo-solar planet imager, which goal is to detect giant exo-solar planets in the vicinity of bright stars and to characterize them through spectroscopic and polarimetric observations. It is a complete system with a core made of an extreme-Adaptive Optics (AO) wavefront correction, a pupil tracker and diffraction suppression through a variety of coronagraphs. At its back