Searching for planets by differential astrometry with large telescopes

Dekany, Richard; Angel, Roger; Hege, K.; Wittman, David

doi:10.1007/bf00984534

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…Han (1989) showed that a 1 mas/h precision can be reached for a double star with ϑ = 1 ′ . Similar conclusions were derived by Gatewood (1991) and Dekany et al (1994).…”

Section: Ground-based Experimentssupporting

confidence: 89%

“…The measurement could be, for example, intrinsically one-dimensional, as is the case for space missions such as ESA's Hipparcos (Perryman et al 1997) and Gaia (Perryman et al 2001), which are designed to perform angular position measurements in their sensitive directions by centroiding their diffraction-limited images. Or it could be a set of two coordinates on the focal plane of the instrument, as is the case for ground-based telescopes (e.g., Gatewood 1987;Dekany et al 1994;Pravdo & Shaklan 1996). Finally, it could be the optical path-length difference between the two arms of an interferometer on the ground (Shao et al 1988;Armstrong et al 1998;van Belle et al 1998;Glindemann et al 2003) or in space, such as NASA's Space Interferometry Mission (SIM; Danner & Unwin 1999), or the normalized difference between the signals of two photomultiplier tubes (the transfer function) of a space-borne interferometer, such as the Hubble Space Telescope fine guidance sensor (HST FGS ;Taff 1990).…”

Section: Observable Modelmentioning

confidence: 99%

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Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review

Sozzetti¹

2005

PUBL ASTRON SOC PAC

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I present a review of astrometric techniques and instrumentation utilized to search for, detect, and characterize extra-solar planets. First, I briefly summarize the properties of the present-day sample of extrasolar planets, in connection with predictions from theoretical models of planet formation and evolution. Next, the generic approach to planet detection with astrometry is described, with significant discussion of a variety of technical, statistical, and astrophysical issues to be faced by future ground-based as well as space-borne efforts in order to achieve the required degree of measurement precision. After a brief summary of past and present efforts to detect planets via milli-arcsecond astrometry, I then discuss the planet-finding capabilities of future astrometric observatories aiming at micro-arcsecond precision. Lastly, I outline a number experiments that can be conducted by means of high-precision astrometry during the next decade, to illustrate its potential for important contributions to planetary science, in comparison with other indirect and direct methods for the detection and characterization of planetary systems.Subject headings: astrometry -planetary systems -stars: statistics -instrumentation: miscellaneous -methods: statistical -methods: numerical massive, close-in planets. These objects are the easiest to detect with the Doppler method 3 , thus the paucity of high-mass planets on short-period orbits is real, and not due to selection effects.Regardless of the formation mode, orbital migration effects are the likely responsible for the observed M p sin i − P correlation. Many models can reproduce such results, including reduced migration efficiency due to gap opening (Ward 1997;Trilling et al. 2002), substantial mass-loss through Roche lobe overflow (Trilling et al. 1998;Gu et al. 2003), and accelerated orbital decay due to enhanced tidal interactions with the host stars (Pätzold & Rauer 2002). Finally, Ida & Lin (2004a) have derived a theoretical mass-period diagram that closely resembles the one of the extrasolar planet sample, and predicted a paucity of planets in the intermediate mass range 0.05 ≤ M p ≤ 0.5 M J , for orbital distances < 3 AU.The possibility that super-solar metallicity could correspond to a higher likelihood of a given star to harbor a planet has been the subject of a large number of studies (for a detailed review see Gonzalez 2003). Recent works (e.g., Santos et al. 2001Santos et al. , 2004aFischer & Valenti 2005) have conclusively shown that planet occurrence correlates strongly with the host stars' primordial metallicity. Up to ∼ 20% of metal-rich ([Fe/H] 0.3) F-G-K stars harbor planets, while less than 3% of metal-poor stars ([Fe/H] 0.0) have been found to be planet hosts.

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“…Han (1989) showed that a 1 mas/h precision can be reached for a double star with ϑ = 1 ′ . Similar conclusions were derived by Gatewood (1991) and Dekany et al (1994).…”

Section: Ground-based Experimentssupporting

confidence: 89%

Section: Observable Modelmentioning

confidence: 99%

Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review

Sozzetti¹

2005

PUBL ASTRON SOC PAC

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“…If astrometry is to contribute meaningfully then σ ast 1 mas. There is some expectation that such a precision can be obtained for binary stars (Dekany et al 1994). If so, combined RV+Astrometry surveys of nearby M dwarfs can measure masses of Jupiter and Saturn-mass companions.…”

Section: Shorter Surveysmentioning

confidence: 99%

Detecting Outer Planets in Edge‐on Orbits: Combining Radial Velocity and Astrometric Techniques

Eisner

Kulkarni

2002

ApJ

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The astrometric and radial velocity techniques of extra-solar planet detection attempt to detect the periodic reflex motion of the parent star by extracting this periodic signal from a time-sampled set of observations. The extraction is generally accomplished using periodogram analysis or the functionally equivalent technique of Least Squares fitting of sinusoids. In this paper, we use a Frequentist approach to examine the sensitivity of Least Squares technique when applied to a combination of radial velocity and astrometric observations. We derive a semianalytical expression for the sensitivity and show that the combined approach yields significantly better sensitivity than either technique on its own. We discuss the ramifications of this result to upcoming astrometric surveys with FAME, the Keck Interferometer, and SIM.

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“…Πληρέστερη αναφορά στην μέση κίνηση της εικόνας μπορεί να βρεθεί στη βιβλιογραφία [110,150,52,33,64,158,159].…”

Section: δημοσιεύσειςunclassified

Στοχαστική Βελτιστοποίηση Για Προσαρμοστική Διόρθωση Ατμοσφαιρικών Παραμορφώσεων Στην Αστρονομική Παρατήρηση

Ζακυνθινάκη¹

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Ένα απο τα κυριότερα προβλήματα που απασχολούν τους αστρονόμους είναι η αλλοίωση της εικόνας του ουράνιου θόλου, λόγω της παραμόρφωσης, την οποία υφίσταται η φωτεινή πληροφορία καθώς περνά από τα στροβιλώδη ατμοσφαιρικά στρώματα. Αντισταθμιστικά συστήματα προσαρμοστικής οπτικής σχεδιάζονται ακριβώς για να ακυρώσουν τις φασικές παραμορφώσεις που προκαλούνται λόγω ατμόσφαιρας. Στην παρούσα εργασία μελετάται διεξοδικά η στατική και δυναμική συμπεριφορά και απόδοση ενός προσομοιωμένου συστήματος οδήγησης προσαρμοστικής οπτικής από το στοχαστικό αλγόριθμο βελτιστοποίησης ALOPEX. Ο στοχαστικός αλγόριθμος ALOPEX καλείται να βελτιστοποιήσει την οξύτητα της παρατηρούμενης εικόνας, επεμβαίνοντας στην επιφάνεια του καθρέπτη και ακυρώνοντας τις επιβαλλόμενες φυσικές παραμορφώσεις. Τη συνάρτηση κόστους του στοχαστικού αλγόριθμου αποτελεί η ποιότητα της παρατηρούμενης εικόνας μιάς σημειακής πηγής. Οι παράμετροι της διαδικασίας είναι ο θόρυβος της στοχαστικής διαδικασίας, ο αλγόριθμος των μεταβλητών ελέγχου, η επιλογή της συνάρτησης κόστους, το εύρος της οπής και ο ρυθμός μεταβολής των ατμοσφαιρικών συνθηκών. Τις μεταβλητές ελέγχου αποτελούν οι θέσεις των κομματιών ενός τμηματικού καθρέπτη, οι συντελεστές του πολυωνυμικού αναπτύγματος Zernike, ή οι θέσεις των ηλεκτρονικών προωθητών που ελέγχουν την επιφάνεια ενός παραμορφώσιμου καθρέπτη.

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Searching for planets by differential astrometry with large telescopes

Cited by 5 publications

References 10 publications

Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review

Astrometric Methods and Instrumentation to Identify and Characterize Extrasolar Planets: A Review

Detecting Outer Planets in Edge‐on Orbits: Combining Radial Velocity and Astrometric Techniques

Στοχαστική Βελτιστοποίηση Για Προσαρμοστική Διόρθωση Ατμοσφαιρικών Παραμορφώσεων Στην Αστρονομική Παρατήρηση

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