The Carnegie Astrometric Planet Search Program

Boss, Alan P.; Weinberger, Alycia J.; Anglada-Escudé, G.; Thompson, I. B.; Burley, Greg; Birk, Christoph; Pravdo, S. H.; Shaklan, Stuart; Gatewood, George; Majewski, Steven R.; Patterson, Richard J.

doi:10.1086/647960

Cited by 72 publications

(62 citation statements)

References 55 publications

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“…Since the reference stars are fainter than the target, this is a conservative estimate of the real precision for the target. The star itself, which is not included in the reference frame, shows a standard deviation in the residuals of 1.0 mas/epoch, which is also consistent with the expected CAPSCam performance, assuming 20 min of on-sky observations per epoch (see Boss et al 2009). Then, we simulate 10 5 synthetic sets of astrometric observations (same format as Table 1) using the nominal parallax and proper motion at the same epochs of observation.…”

Section: Astrometry and Trigonometric Parallaxsupporting

confidence: 75%

“…Each epoch consists of 20 or more exposures of 45 s each. GJ 1214 is significantly brighter than the average background sources and would saturate the detector in less than 10 s. However CAPSCam can read out a small part of the array much faster than the full field (Boss et al 2009). For GJ 1214, a window of 64 × 64 pixels is read out every 5 s, and all subrasters are added to the final full field image.…”

Section: Astrometry and Trigonometric Parallaxmentioning

confidence: 99%

“…Centroid extraction, source crossmatching, field distortion correction, and astrometric solutions for all the stars in the field have been obtained using the ATPa astrometric software developed within the CAPS project (available upon request). The methods and algorithms applied are outlined in Boss et al (2009) and Anglada-Escudé et al (2012b).…”

Section: Astrometry and Trigonometric Parallaxmentioning

confidence: 99%

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GJ 1214 reviewed

Anglada-Escudé

Rojas-Ayala

Boss

et al. 2013

A&A

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Context. GJ 1214 is orbited by a transiting super-Earth-mass planet. It is a primary target for ongoing efforts to understand the emerging population of super-Earth-mass planets around M dwarfs, some of which are detected within the liquid water (habitable) zone of their host stars. Aims. We present new precision astrometric measurements, a re-analysis of HARPS radial velocity measurements, and new mediumresolution infrared spectroscopy of GJ 1214. We combine these measurements with recent transit follow-up observations and new catalog photometry to provide a comprehensive update of the star-planet properties. Methods. The distance is obtained with 0.6% relative uncertainty using CAPScam astrometry. The new value increases the nominal distance to the star by ∼10% and is significantly more precise than previous measurements. Improved radial velocity measurements have been obtained analyzing public HARPS spectra of GJ 1214 using the HARPS-TERRA software and are 25% more precise than the original ones. The Doppler measurements combined with recently published transit observations significantly refine the constraints on the orbital solution, especially on the planet's eccentricity. The analysis of the infrared spectrum and photometry confirm that the star is enriched in metals compared to the Sun. Results. Using all this new fundamental information, combined with empirical mass-luminosity relations for low mass stars, we derive updated values for the bulk properties of the star-planet system. We also use infrared absolute fluxes to estimate the stellar radius and to re-derive the star-planet properties. Both approaches provide very consistent values for the system. Our analysis shows that the updated expected value for the planet mean density is 1.6 ± 0.6 g cm −3 , and that a density comparable to the Earth (∼5.5 g cm −3 ) is now ruled out with very high confidence. Conclusions. This study illustrates how the fundamental properties of M dwarfs are of paramount importance in the proper characterization of the low mass planetary candidates orbiting them. Given that the distance is now known to better than 1%, interferometric measurements of the stellar radius, additional high precision Doppler observations, and/or or detection of the secondary transit (occultation), are necessary to further improve the constraints on the GJ 1214 star-planet properties.

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Section: Astrometry and Trigonometric Parallaxsupporting

confidence: 75%

Section: Astrometry and Trigonometric Parallaxmentioning

confidence: 99%

Section: Astrometry and Trigonometric Parallaxmentioning

confidence: 99%

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GJ 1214 reviewed

Anglada-Escudé

Rojas-Ayala

Boss

et al. 2013

A&A

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“…The findings presented herein are the result of more than 15 years of high-precision Doppler monitoring of nearby stars. Additional information will soon pour in from other surveys using techniques such as microlensing (e.g., Dong et al 2009;Gould et al 2010), astrometry (Boss et al 2009), transits (Borucki et al 2004;Barge et al 2008;Irwin et al 2009), and direct imaging (Claudi et al 2006;Artigau et al 2008;Macintosh et al 2008).…”

Section: Summary and Discussionmentioning

confidence: 99%

Giant Planet Occurrence in the Stellar Mass-Metallicity Plane

Johnson¹,

Aller²,

Howard³

et al. 2010

PUBL ASTRON SOC PAC

757

824

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ABSTRACT. Correlations between stellar properties and the occurrence rate of exoplanets can be used to inform the target selection of future planet-search efforts and provide valuable clues about the planet-formation process. We analyze a sample of 1266 stars drawn from the California Planet Survey targets to determine the empirical functional form describing the likelihood of a star harboring a giant planet as a function of its mass and metallicity. Our stellar sample ranges from M dwarfs with masses as low as 0:2 M ⊙ to intermediate-mass subgiants with masses as high as 1:9 M ⊙ . In agreement with previous studies, our sample exhibits a planet-metallicity correlation at all stellar masses; the fraction of stars that harbor giant planets scales as f ∝ 10 1:2½Fe=H . We can rule out a flat metallicity relationship among our evolved stars (at 98% confidence), which argues that the high metallicities of stars with planets is not likely due to convective envelope "pollution." Our data also rule out a constant planet occurrence rate for ½Fe=H < 0, indicating that giant planets continue to become rarer at sub-Solar metallicities. We also find that planet occurrence increases with stellar mass (f ∝ M ⋆ ), characterized by a rise from 3% around M dwarfs (0:5 M ⊙ ) to 14% around A stars (2 M ⊙ ), at Solar metallicity. We argue that the correlation between stellar properties and giant planet occurrence is strong supporting evidence of the core-accretion model of planet formation.

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“…Planets with masses between 1 and 10 M Earth , ''super-Earths,'' have indeed been detected in the last few years around low-mass stars, such as Gl 581 d and Gl 667C c by radial velocity (Udry et al, 2007;Mayor et al, 2009;Vogt et al, 2010;Bonfils et al, 2011;Forveille et al, 2011;AngladaEscudé et al, 2012;Delfosse et al, 2012) and GJ 1214 b by transit (Charbonneau et al, 2009;Sada et al, 2010;Carter et al, 2011;Kundurthy et al, 2011). Several observational campaigns designed specifically to detect planets around low-mass stars are now underway (Nutzman and Charbonneau, 2008;Boss et al, 2009;Zechmeister et al, 2009;Bean et al, 2010;Rodler et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

et al. 2013

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Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at highenough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets ''Tidal Venuses'' and the phenomenon a ''tidal greenhouse.'' Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with masses < 0.3 M Sun may be in danger of desiccation via tidal heating. We have applied these concepts to Gl 667C c, a *4.5 M Earth planet orbiting a 0.3 M Sun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

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The Carnegie Astrometric Planet Search Program

Cited by 72 publications

References 55 publications

GJ 1214 reviewed

GJ 1214 reviewed

Giant Planet Occurrence in the Stellar Mass-Metallicity Plane

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

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