Analytic Study of Grid Star and Reference Star Selection for the<i>Space Interferometry Mission</i>

Gould, Andrew

doi:10.1086/322334

Cited by 6 publications

(11 citation statements)

References 7 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our own simulations show that with 200 observations, SIM can detect and characterize systems with two or three short-period planets as long as their periods are well-separated, which should be the case if they are in dynamically stable orbits. Gas giant companions with periods longer than the mission length are hard to detect, because SIM would detect an acceleration, but not obtain data for a closed orbit (Gould 2001). However, SIM can generate valuable statistical data on long-period planets, even if the periods are very uncertain, because these planets are undetectable with RV measurements and too faint for direct imaging.…”

Section: Detecting Multiple Planetsmentioning

confidence: 99%

“…For periods up to ∼ 10 years, estimates of orbital parameters, including period, can be made, but as the period lengthens, the uncertainties grow quickly. In the limiting case, SIM can only make a detection of the acceleration due to a companion (Gould 2001). Even though the parameters of any one such target may not be well-determined, important statistical conclusions can be drawn from an ensemble of long-period systems.…”

Section: How Unique Is the Solar System?mentioning

confidence: 99%

“…Thus, for a given brightness, K giant stars are 5 − 10 times more distant than F and G dwarfs. Astrometric motions induced by unseen stellar and planetary companions are of course minimized by the increased distance (e.g., Gould 2001;Frink et al 2001;Peterson, Liu & Portegies Zwart 2002).…”

Section: Selection Of Sim Grid Starsmentioning

confidence: 99%

See 2 more Smart Citations

Taking the Measure of the Universe: Precision Astrometry withSIM PlanetQuest

Unwin¹,

Shao²,

Tanner³

et al. 2008

PUBL ASTRON SOC PAC

154

View full text Add to dashboard Cite

Precision astrometry at microarcsecond accuracy has application to a wide range of astrophysical problems. This paper is a study of the science questions that can be addressed using an instrument with flexible scheduling that delivers parallaxes at about 4 microarcsec (µas) on targets as faint as V = 20, and differential accuracy of 0.6 µas on bright targets. The science topics are drawn primarily from the Team Key Projects, selected in 2000, for the Space Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities of this mission to illustrate the importance of the next level of astrometric precision in modern astrophysics.SIM PlanetQuest is currently in the detailed design phase, having completed in 2005 all of the enabling technologies needed for the flight instrument. It will be the first space-based long baseline Michelson interferometer designed for precision astrometry. SIM will contribute strongly to many astronomical fields including stellar and galactic astrophysics, planetary systems around nearby stars, and the study of quasar and AGN nuclei. Using differential astrometry SIM will search for planets with masses as small as an Earth orbiting in the 'habitable zone' around the nearest stars, and could discover many dozen if Earth-like planets are common. It will characterize the multiple-planet systems that are now known to exist, and it will be able to search for terrestrial planets around all of the candidate target stars in the Terrestrial Planet Finder and Darwin mission lists. It will be capable of detecting planets around young stars, thereby providing insights into how planetary systems are born and how they evolve with time. Precision astrometry allows the measurement of accurate dynamical masses for stars in binary systems. SIM will observe significant numbers of very high-and low-mass stars, providing stellar masses to 1%, the accuracy needed to challenge physical models. Using precision proper motion measurements, SIM will probe the Galactic mass distribution, and through studies of tidal tails, the formation and evolution of the Galactic halo. SIM will contribute to cosmology through improved accuracy of the Hubble Constant. With repeated astrometric measurements of the nuclei of active galaxies, SIM will probe the dynamics of accretion disks around supermassive black holes, and the relativistic jets that emerge from them.

show abstract

Section: Detecting Multiple Planetsmentioning

confidence: 99%

Section: How Unique Is the Solar System?mentioning

confidence: 99%

See 1 more Smart Citation

Taking the Measure of the Universe: Precision Astrometry withSIM PlanetQuest

Unwin¹,

Shao²,

Tanner³

et al. 2008

PUBL ASTRON SOC PAC

154

View full text Add to dashboard Cite

show abstract

“…A typical strategy to achieve this, adopted for example for the selection of the grid stars for SIM , is to look for reference objects that are K giants, and pre-select them on the basis of mediumprecision radial-velocity monitoring. In this case, the typically large distance of these stars (1 kpc) implies (provided they are not too faint, otherwise photon noise becomes an issue) a significant suppression of any astrometric signature that might significantly pollute the potential planetary signal from the target (e.g., Gould 2001, and references therein).…”

Section: Astrophysical Noisementioning

confidence: 99%

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

Sozzetti¹

2005

PUBL ASTRON SOC PAC

View full text Add to dashboard Cite

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.

show abstract

“…For the narrow-angle observation mode of SIM PlanetQuest, the differential fringe delays are measured by so-called chopping technique. That observation "chops" between target and reference stars every 90 seconds and thermal drift noise becomes "white" after chopping 3 . In that case more than four reference stars are used with separations of less than 1 degree from target star.…”

Section: Requirements and Distributions Of Reference Starsmentioning

confidence: 99%

Analysis of planet effect of reference star on searching for Earth-like planets

Pan

Shao

2008

SPIE Proceedings

View full text Add to dashboard Cite

It is a challenging task to find exoplanets because of the huge contrast between star and planets in mass and in brightness. It is more challenging to determine the masses of exoplanets because it requires extremely high astrometric accuracy. In particular detection of Earth-like planets needs sub-microarcsecond (µas) precision which is possible only by narrow-angle astrometry via the SIM PlanetQuest mission. The narrow-angle observation mode of SIM PlanetQuest requires several distant reference stars, which are close enough in the sky around the target, typically within one degree. This paper provides statistical estimates of available reference stars for all candidate stars in searching for Earth-like planets.It is inevitable that some of reference stars will have binary components and planets. This paper describes the analysis techniques and various error estimates for binary jitters and planet effects of reference stars. Because of the limited number and duration of observations of SIM PlanetQuest, the Monte Carlo simulations indicate that certain long period planets around reference stars may not be detected. Earth-like planets around target stars, however, can be detected unambiguously. Finally, we demonstrate the current best estimates of instrument error, photon noise, reference stars planet disturbance, stellar jitters, etc., and conclude that the orbits of Earth-like planets with sub-µas astrometric signatures can be determined accurately by SIM PlanetQuest for nearby candidate stars.

show abstract

Analytic Study of Grid Star and Reference Star Selection for theSpace Interferometry Mission

Cited by 6 publications

References 7 publications

Taking the Measure of the Universe: Precision Astrometry withSIM PlanetQuest

Taking the Measure of the Universe: Precision Astrometry withSIM PlanetQuest

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

Analysis of planet effect of reference star on searching for Earth-like planets

Contact Info

Product

Resources

About