scholarly journals HST/STIS imaging of Fomalhaut: New main belt structure and confirmation of Fomalhaut b's eccentric orbit

2013 ◽  
Vol 8 (S299) ◽  
pp. 204-207 ◽  
Author(s):  
P. Kalas ◽  
J. R. Graham ◽  
M. P. Fitzgerald ◽  
M. Clampin
Keyword(s):  
Hubble Space Telescope ◽  
Main Belt ◽  
Contrast Imaging ◽  
Nearby Star ◽  
High Contrast Imaging ◽  
Reflected Light ◽  
New Findings ◽  
Low Mass ◽  
Dust Ring ◽  
Made In

AbstractHigh contrast imaging observations with the Hubble Space Telescope show that the nearby star Fomalhaut is surrounded by a dusty debris belt and a candidate planet, Fomalhaut b, located just inside the edge of the belt. Fomalhaut b has unexpected characteristics, such as a relatively blue spectrum, leading to the hypothesis that the detected object is a low-mass planet hosting a giant planetary dust ring or cloud seen in reflected light. Here we present new HST/STIS observations made in 2010 and 2012 that authenticate the existence of Fomalhaut b. Our MCMC analysis of four epochs of astrometry spread over eight years indicate that the orbit has a~170 AU and e~0.85. Fomalhaut b's orbit is apsidally aligned with the main belt, and periapse is located approximately ~30 AU south of the star. We also show the existence of a ~50 AU wide azimuthal dust depletion in the dust belt. These new findings provide a revised picture of Fomalhaut as a dynamically complex system, where the orbit of Fomalhaut b and the belt structure signify the presence of additional massive planets orbiting the star.

scholarly journals High-contrast Imaging with Fizeau Interferometry: the Case of Altair*

2022 ◽  
Vol 163 (2) ◽  
pp. 62
Author(s):  
E. Spalding ◽  
K. M. Morzinski ◽  
P. Hinz ◽  
J. Males ◽  
M. Meyer ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Active Phase ◽  
Phase Detector ◽  
Integration Time ◽  
Data Sets ◽  
Contrast Imaging ◽  
Science Data ◽  
Data Set ◽  
Nearby Star ◽  
High Contrast Imaging

Abstract The Large Binocular Telescope (LBT) has two 8.4 m primary mirrors that produce beams that can be combined coherently in a “Fizeau” interferometric mode. In principle, the Fizeau point-spread function (PSF) enables the probing of structure at a resolution up to three times better than that of the adaptive-optics-corrected PSF of a single 8.4 m telescope. In this work, we examined the nearby star Altair (5.13 pc, type A7V, hundreds of Myr to ≈1.4 Gyr) in the Fizeau mode with the LBT at Brα (4.05 μm) and carried out angular differential imaging to search for companions. This work presents the first filled-aperture LBT Fizeau science data set to benefit from a correcting mirror that provides active phase control. In the analysis of the λ/D angular regime, the sensitivity of the data set is down to ≈0.5 M ⊙ at 1″ for a 1.0 Gyr system. This sensitivity remains limited by the small amount of integration time, which is in turn limited by the instability of the Fizeau PSF. However, in the Fizeau fringe regime we attain sensitivities of Δm ≈ 5 at 0.″2 and put constraints on companions of 1.3 M ⊙ down to an inner angle of ≈0.″15, closer than any previously published direct imaging of Altair. This analysis is a pathfinder for future data sets of this type, and represents some of the first steps to unlocking the potential of the first Extremely Large Telescope. Fizeau observations will be able to reach dimmer targets with upgrades to the instrument, in particular the phase detector.

scholarly journals The SOPHIE search for northern extrasolar planets

2019 ◽  
Vol 625 ◽  
pp. A17 ◽  
Author(s):  
R. F. Díaz ◽  
X. Delfosse ◽  
M. J. Hobson ◽  
I. Boisse ◽  
N. Astudillo-Defru ◽  
...  
Keyword(s):  
Extrasolar Planets ◽  
Equilibrium Temperature ◽  
Current Data ◽  
Velocity Variation ◽  
High Dispersion ◽  
Correlated Noise ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Independent Analysis ◽  
Low Mass

Periodic radial velocity variations in the nearby M-dwarf star Gl 411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08 days, but favour the former slightly. The velocity variation has an amplitude of 1.6 m s−1, making this the lowest-amplitude signal detected with SOPHIE up to now. We have performed a detailed analysis of the significance of the signal and its origin, including extensive simulations with both uncorrelated and correlated noise, representing the signal induced by stellar activity. The signal is significantly detected, and the results from all tests point to its planetary origin. Additionally, the presence of an additional acceleration in the velocity time series is suggested by the current data. On the other hand, a previously reported signal with a period of 9.9 days, detected in HIRES velocities of this star, is not recovered in the SOPHIE data. An independent analysis of the HIRES dataset also fails to unveil the 9.9-day signal. If the 12.95-day period is the real one, the amplitude of the signal detected with SOPHIE implies the presence of a planet, called Gl 411 b, with a minimum mass of around three Earth masses, orbiting its star at a distance of 0.079 AU. The planet receives about 3.5 times the insolation received by Earth, which implies an equilibrium temperature between 256 and 350 K, and makes it too hot to be in the habitable zone. At a distance of only 2.5 pc, Gl 411 b, is the third closest low-mass planet detected to date. Its proximity to Earth will permit probing its atmosphere with a combination of high-contrast imaging and high-dispersion spectroscopy in the next decade.

scholarly journals A temperate exo-Earth around a quiet M dwarf at 3.4 parsec

2018 ◽  
Vol 613 ◽  
pp. A25 ◽  
Author(s):  
X. Bonfils ◽  
N. Astudillo-Defru ◽  
R. Díaz ◽  
J.-M. Almenara ◽  
T. Forveille ◽  
...  
Keyword(s):  
Giant Planet ◽  
Angular Separation ◽  
Magnetic Activity ◽  
High Dispersion ◽  
Contrast Imaging ◽  
M Dwarfs ◽  
High Contrast Imaging ◽  
Habitable Zones ◽  
Low Mass ◽  
Large Telescopes

The combination of high-contrast imaging and high-dispersion spectroscopy, which has successfully been use to detect the atmosphere of a giant planet, is one of the most promising potential probes of the atmosphere of Earth-size worlds. The forthcoming generation of extremely large telescopes (ELTs) may obtain sufficient contrast with this technique to detect O2 in the atmosphere of those worlds that orbit low-mass M dwarfs. This is strong motivation to carry out a census of planets around cool stars for which habitable zones can be resolved by ELTs, i.e. for M dwarfs within ~5 parsec. Our HARPS survey has been a major contributor to that sample of nearby planets. Here we report on our radial velocity observations of Ross 128 (Proxima Virginis, GJ447, HIP 57548), an M4 dwarf just 3.4 parsec away from our Sun. This source hosts an exo-Earth with a projected mass m sini = 1.35 M⊕ and an orbital period of 9.9 days. Ross 128 b receives less than 1.5 times as much flux as Earth from the Sun and its equilibrium ranges in temperature between 269 K for an Earth-like albedo and 213 K for a Venus-like albedo. Recent studies place it close to the inner edge of the conventional habitable zone. An 80-day long light curve from K2 campaign C01 demonstrates that Ross 128 b does not transit. Together with the All Sky Automated Survey (ASAS) photometry and spectroscopic activity indices, the K2 photometry shows that Ross 128 rotates slowly and has weak magnetic activity. In a habitability context, this makes survival of its atmosphere against erosion more likely. Ross 128 b is the second closest known exo-Earth, after Proxima Centauri b (1.3 parsec), and the closest temperate planet known around a quiet star. The 15 mas planet-star angular separation at maximum elongation will be resolved by ELTs (>3λ∕D) in the optical bands of O2.

scholarly journals SPOTS: The Search for Planets Orbiting Two Stars

2018 ◽  
Vol 619 ◽  
pp. A43 ◽  
Author(s):  
R. Asensio-Torres ◽  
M. Janson ◽  
M. Bonavita ◽  
S. Desidera ◽  
C. Thalmann ◽  
...  
Keyword(s):  
Binary Stars ◽  
Imaging Techniques ◽  
Contrast Imaging ◽  
Direct Imaging ◽  
Upper Limit ◽  
High Contrast Imaging ◽  
Survey Results ◽  
Low Mass ◽  
Best Fit ◽  
Observational Program

Binary stars constitute a large percentage of the stellar population, yet relatively little is known about the planetary systems orbiting them. Most constraints on circumbinary planets (CBPs) so far come from transit observations with the Kepler telescope, which is sensitive to close-in exoplanets but does not constrain planets on wider orbits. However, with continuous developments in high-contrast imaging techniques, this population can now be addressed through direct imaging. We present the full survey results of the Search for Planets Orbiting Two Stars (SPOTS) survey, which is the first direct imaging survey targeting CBPs. The SPOTS observational program comprises 62 tight binaries that are young and nearby, and thus suitable for direct imaging studies, with VLT/NaCo and VLT/SPHERE. Results from SPOTS include the resolved circumbinary disk around AK Sco, the discovery of a low-mass stellar companion in a triple packed system, the relative astrometry of up to 9 resolved binaries, and possible indications of non-background planetary-mass candidates around HIP 77911. We did not find any CBP within 300 AU, which implies a frequency upper limit on CBPs (1–15 MJup) of 6–10% between 30–300 AU. Coupling these observations with an archival dataset for a total of 163 stellar pairs, we find a best-fit CBP frequency of 1.9% (2–15 MJup) between 1 and 300 AU with a 10.5% upper limit at a 95% confidence level. This result is consistent with the distribution of companions around single stars.

scholarly journals ISPY – NaCo Imaging Survey for Planets around Young stars

2019 ◽  
Vol 624 ◽  
pp. A29 ◽  
Author(s):  
G. Cugno ◽  
S. P. Quanz ◽  
R. Launhardt ◽  
A. Musso Barcucci ◽  
S. S. Brems ◽  
...  
Keyword(s):  
Circular Orbit ◽  
Position Angle ◽  
Young Stars ◽  
Imaging Data ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Very Large Telescope ◽  
Low Mass ◽  
Background Object ◽  
One Year

Context. Within the NaCo-ISPY exoplanet imaging program, we aim at detecting and characterizing the population of low-mass companions at wide separations (≳10 AU), focusing in particular on young stars either hosting a known protoplanetary disk or a debris disk. Aims. R CrA is one of the youngest (1–3 Myr) and most promising objects in our sample because of two previous studies that suggested the presence of a close companion. Our aim is to directly image and characterize the companion for the first time. Methods. We observed R CrA twice with the NaCo instrument at the Very Large Telescope (VLT) in the L′ filter with a one year time baseline in between. The high-contrast imaging data were reduced and analyzed and the companion candidate was detected in both datasets. We used artificial negative signals to determine the position and brightness of the companion and the related uncertainties. Results. The companion is detected at a separation of 196.8 ± 4.5/196.6 ± 5.9 mas (18.7 ± 1.3/18.7 ± 1.4 AU) and position angle of 134.7 ± 0.5 ° /133.7 ± 0.7° in the first/second epoch observation. We measure a contrast of 7.29 ± 0.18/6.70 ± 0.15 mag with respect to the primary. A study of the stellar proper motion rejects the hypothesis that the signal is a background object. The companion candidate orbits in the clockwise direction and, if on a face-on circular orbit, its period is ∼43 − 47 yr. This value disagrees with the estimated orbital motion and therefore a face-on circular orbit may be excluded. Depending on the assumed age, extinction, and brightness of the primary, the stellar companion has a mass between 0.10 ± 0.02 M⊙ and 1.03−0.18+0.20 M⊙ range, if no contribution from circumsecondary material is taken into account. Conclusions. As already hypothesized by previous studies, we directly detected a low-mass stellar companion orbiting the young Herbig Ae/Be star R CrA. Depending on the age assumptions, the companion is among the youngest forming companions imaged to date, and its presence needs to be taken into account when analyzing the complex circumstellar environment of R CrA.

scholarly journals Two cold belts in the debris disk around the G-type star NZ Lupi

2019 ◽  
Vol 625 ◽  
pp. A21 ◽  
Author(s):  
A. Boccaletti ◽  
P. Thébault ◽  
N. Pawellek ◽  
A.-M. Lagrange ◽  
R. Galicher ◽  
...  
Keyword(s):  
Scattered Light ◽  
Planetary Systems ◽  
High Angular Resolution ◽  
High Contrast ◽  
Contrast Imaging ◽  
Nearby Star ◽  
Imaging Device ◽  
High Contrast Imaging ◽  
Debris Disk ◽  
Dust Distribution

Context. Planetary systems hold the imprint of the formation and of the evolution of planets especially at young ages, and in particular at the stage when the gas has dissipated leaving mostly secondary dust grains. The dynamical perturbation of planets in the dust distribution can be revealed with high-contrast imaging in a variety of structures. Aims. SPHERE, the high-contrast imaging device installed at the VLT, was designed to search for young giant planets in long period, but is also able to resolve fine details of planetary systems at the scale of astronomical units in the scattered-light regime. As a young and nearby star, NZ Lup was observed in the course of the SPHERE survey. A debris disk had been formerly identified with HST/NICMOS. Methods. We observed this system in the near-infrared with the camera in narrow and broad band filters and with the integral field spectrograph. High contrasts are achieved by the mean of pupil tracking combined with angular differential imaging algorithms. Results. The high angular resolution provided by SPHERE allows us to reveal a new feature in the disk which is interpreted as a superimposition of two belts of planetesimals located at stellocentric distances of ~85 and ~115 au, and with a mutual inclination of about 5°. Despite the very high inclination of the disk with respect to the line of sight, we conclude that the presence of a gap, that is, a void in the dust distribution between the belts, is likely. Conclusions. We discuss the implication of the existence of two belts and their relative inclination with respect to the presence of planets.

scholarly journals In a Mechanism Far, Far Away

2004 ◽  
Vol 126 (04) ◽  
pp. 40-41
Keyword(s):  
Space Flight ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Primary Mirror ◽  
Nasa Goddard Space ◽  
James Webb Space Telescope ◽  
Goddard Space Flight Center ◽  
Nose Cone ◽  
Low Mass ◽  
Made In

This article describes features of James Webb Space Telescope, which is going to take the place of the Hubble Space Telescope in 2011. The Webb telescope is an orbiting infrared observatory, and the project is managed by the NASA Goddard Space Flight Center in Greenbelt, Maryland. The Webb Space Telescope will use extremely large aperture, low-mass mirrors. Made in segments so they can be folded to fit into a rocket nose cone for flight, they will open and array themselves when they reach their destination. These robust mirrors must be fabricated rapidly and cost-effectively. There are significant manufacturing challenges in the composite backplanes for the primary mirror. These are to be made from boron composites for their stiffness. The analysis and manufacturing challenges in the backplane are the adhesives used to combine all the composite parts and the uniformity to which the composites themselves can be manufactured. The structure of the primary mirror for the Webb Telescope permits small adjustments.

scholarly journals Adaptive Optics Observations of Exoplanets, Brown Dwarfs, and Binary Stars

2011 ◽  
Vol 7 (S282) ◽  
pp. 181-188
Author(s):  
Sasha Hinkley
Keyword(s):  
Adaptive Optics ◽  
Binary Stars ◽  
Imaging Techniques ◽  
Contrast Ratio ◽  
Brown Dwarfs ◽  
Formation Mechanisms ◽  
High Contrast ◽  
Contrast Imaging ◽  
High Contrast Imaging ◽  
Low Mass

AbstractThe current direct observations of brown dwarfs and exoplanets have been obtained using instruments not specifically designed for overcoming the large contrast ratio between the host star and any wide-separation faint companions. However, we are about to witness the birth of several new dedicated observing platforms specifically geared towards high contrast imaging of these objects. The Gemini Planet Imager, VLT-SPHERE, Subaru HiCIAO, and Project 1640 at the Palomar 5m telescope will return images of numerous exoplanets and brown dwarfs over hundreds of observing nights in the next five years. Along with diffraction-limited coronagraphs and high-order adaptive optics, these instruments also will return spectral and polarimetric information on any discovered targets, giving clues to their atmospheric compositions and characteristics. Such spectral characterization will be key to forming a detailed theory of comparative exoplanetary science which will be widely applicable to both exoplanets and brown dwarfs. Further, the prevalence of aperture masking interferometry in the field of high contrast imaging is also allowing observers to sense massive, young planets at solar system scales (~3–30 AU)— separations out of reach to conventional direct imaging techniques. Such observations can provide snapshots at the earliest phases of planet formation—information essential for constraining formation mechanisms as well as evolutionary models of planetary mass companions. As a demonstration of the power of this technique, I briefly review recent aperture masking observations of the HR 8799 system. Moreover, all of the aforementioned techniques are already extremely adept at detecting low-mass stellar companions to their target stars, and I present some recent highlights.

Sign in / Sign up

Export Citation Format

Share Document