The HARPS search for southern extra-solar planets

Udry, S.; Bonfils, X.; Delfosse, X.; Forveille, T.; Mayor, M.; Perrier, C.; Bouchy, F.; Lovis, C.; Pepe, F.; Queloz, D.; Bertaux, Jean-Loup

doi:10.1051/0004-6361:20077612

Cited by 454 publications

(423 citation statements)

References 19 publications

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“…finding one of these planets may be even higher in metal-poor stars, and they appear to exhibit a different trend from the Jovianhost stars. Our results for stars hosting only Neptunian-like planets agree with those of Udry et al (2006Udry et al ( , 2007 and Sousa et al (2008) for [Fe/H]. …”

Section: Distribution [X/h]supporting

confidence: 87%

Chemical abundances of 451 stars from the HARPS GTO planet search program

Neves

Santos

Sousa

et al. 2009

A&A

154

236

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We present a uniform study of the chemical abundances of 12 elements (Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Na, Mg, and Al) derived from the spectra of 451 stars observed as part of one of the HARPS GTO planet search programs. Sixty eight of these are planetbearing stars. The main goals of our work are: i) the investigation of possible differences between the abundances of stars with and without planets; ii) the study of the possible differences in the abundances of stars in the thin and the thick disc. We confirm that there is a systematically higher metallicity in planet host stars, when compared to non planet-hosts, common to all studied species. We also found that there is no difference in the galactic chemical evolution trends of the stars with and without planets. Stars that harbour planetary companions simply appear to be in the high metallicity tail of the distribution. We also confirm that Neptunian and super-Earth class planets may be easier to find at lower metallicities. A statistically significative abundance difference between stars of the thin and the thick disc was found for [Fe/H] < 0. However, the populations from the thick and the thin disc cannot be clearly separated.

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Section: Distribution [X/h]supporting

confidence: 87%

Chemical abundances of 451 stars from the HARPS GTO planet search program

Neves

Santos

Sousa

et al. 2009

A&A

154

236

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“…The true period of planet g might be either of these values, with the other peak being the yearly alias of that true period. Udry et al (2007) were similarly confused in their original determination of the period of planet d. Their originally reported period of 82 days turned out to be the yearly alias of the true period of 67 days, as 1/82 ∼ (1/67 -1/365.25). This was subsequently corrected in M09 to the true period of 67 days for planet d. Similarly, the 36-day signal reported by V10 for GJ 581g could well have been the yearly alias of a true period of 33 days, as 1/33 ∼ (1/36 + 1/365.25).…”

Section: Discussionmentioning

confidence: 99%

GJ 581 update: Additional evidence for a Super‐Earth in the habitable zone

Vogt

Butler²,

Haghighipour

2012

Astron Nachr

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We present an analysis of the significantly expanded HARPS 2011 radial velocity data set for GJ 581 that was presented by Forveille et al. (2011). Our analysis reaches substantially different conclusions regarding the evidence for a SuperEarth-mass planet in the star's Habitable Zone. We were able to reproduce their reported χ 2 ν and RMS values only after removing some outliers from their models and refitting the trimmed down RV set. A suite of 4000 N-body simulations of their Keplerian model all resulted in unstable systems and revealed that their reported 3.6σ detection of e=0.32 for the eccentricity of GJ 581e is manifestly incompatible with the system's dynamical stability. Furthermore, their Keplerian model, when integrated only over the time baseline of the observations, significantly increases the χ 2 ν and demonstrates the need for including non-Keplerian orbital precession when modeling this system. We find that a four-planet model with all of the planets on circular or nearly circular orbits provides both an excellent self-consistent fit to their RV data and also results in a very stable configuration. The periodogram of the residuals to a 4-planet all-circular-orbit model reveals significant peaks that suggest one or more additional planets in this system. We conclude that the present 240-point HARPS data set, when analyzed in its entirety, and modeled with fully self-consistent stable orbits, by and of itself does offer significant support for a fifth signal in the data with a period near 32 days. This signal has a False Alarm Probability of < 4% and is consistent with a planet of minimum mass 2.2M⊕, orbiting squarely in the star's Habitable Zone at 0.13 AU, where liquid water on planetary surfaces is a distinct possibility.

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“…Assuming that both our measurements are consistent with the orbit of GJ725AB indeed puts a much stronger constraint on its eccentricity, at e0.435. GJ740 (HIP93101) is a nearby, weakly active M0.5 star ) located at 10.91±0.18 pc (van Leeuwen 2007). No precise RV measurements were reported in the literature as of yet.…”

Section: Candidate Rv Variable Targetsmentioning

confidence: 99%

“…GJ9520 (HIP75187) is a nearby M1.5-type (Reid et al 2004) star located at 11.41±0.24 pc (van Leeuwen 2007). No precise RV measurements were reported in the literature for this star as of yet.…”

Section: Candidate Rv Variable Targetsmentioning

confidence: 99%

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné

Plavchan

Gao

et al. 2016

ApJ

232

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We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25-150 Myr) moving groups, the young field star εEridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8-15 m s −1 with a long-term stability of 15-50 m s −1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25-50 m s −1 at ≈2.3125 μm, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ876bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD160934AB and GJ725AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3σ-5σ. Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of 5 m s −1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

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The HARPS search for southern extra-solar planets

Cited by 454 publications

References 19 publications

Chemical abundances of 451 stars from the HARPS GTO planet search program

Chemical abundances of 451 stars from the HARPS GTO planet search program

GJ 581 update: Additional evidence for a Super‐Earth in the habitable zone

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

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