ROTATION–ACTIVITY CORRELATIONS IN K AND M DWARFS. I. STELLAR PARAMETERS AND COMPILATIONS OF v sin i AND P/sin i FOR A LARGE SAMPLE OF LATE-K AND M DWARFS*

Houdebine, E. R.; Mullan, D. J.; Paletou, F.; Gebran, M.

doi:10.3847/0004-637x/822/2/97

Cited by 46 publications

(41 citation statements)

References 91 publications

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“…We find good agreement between our SPECMATCH-EMP derived stellar parameters from the PFS template spectrum and those derived by Niraula et al (2017) and by Houdebine et al (2016) as reported in Rodriguez et al (2017). Our T eff and log g values for GJ 9827 are slightly lower (4085±70 K versus their 4255±110 K and 4270±100 K, 4.67±0.12 cgs versus their 4.70±0.15 cgs and 4.9±0.2 cgs), and our metallicity is Neither Niraula et al (2017) nor Rodriguez et al (2017) report an age estimate for GJ 9827.…”

Section: Introductionsupporting

confidence: 90%

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Teske

Wang

Wolfgang

et al. 2018

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The Kepler mission showed us that planets with sizes between that of Earth and Neptune appear to be the most common type in our Galaxy. These "super-Earths" continue to be of great interest for exoplanet formation, evolution, and composition studies. However, the number of super-Earths with well-constrained mass and radius measurements remains small (40 planets with σ mass < 25%), due in part to the faintness of their host stars causing ground-based mass measurements to be challenging. Recently, three transiting super-Earth planets were detected by the K2 mission around the nearby star GJ 9827/HIP 115752, at only 30 pc away. The radii of the planets span the "radius gap" detected by , and all orbit within ∼6.5 days, easing follow-up observations. Here we report radial velocity (RV) observations of GJ 9827, taken between 2010 and 2016 with the Planet Finder Spectrograph on the Magellan II Telescope. We employ two different RV analysis packages, SYSTEMIC and RADVEL, to derive masses and thus densities of the GJ 9827 planets. We also test a Gaussian Process regression analysis, but find the correlated stellar noise is not well constrained by the PFS data, and that the GP tends to over fit the RV semi-amplitudes arXiv:1711.01359v4 [astro-ph.EP] 28 Feb 2018 2 TESKE ET AL. resulting in a lower K value. Our RV observations are not able to place strong mass constraints on the two outer planets (c & d) but do indicate that planet b, at 1.64 R ⊕ and ∼ 8 M ⊕ , is one of the most massive (and dense) super-Earth planets detected to date.

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Section: Introductionsupporting

confidence: 90%

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Teske

Wang

Wolfgang

et al. 2018

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“…Niraula et al (2017) and Teske et al (2018) used SpecMatch-Emp (Yee et al 2017), the results of which are shown in their Table 3 and Table 2 respectively. The stellar parameters used by Rodriguez et al (2018) are shown in their Table 1 and are taken from Houdebine et al (2016), who used principal component analysis.…”

Section: Stellar Parametersmentioning

confidence: 99%

Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets

Rice

Malavolta

Mayo

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Super-Earths belong to a class of planet not found in the Solar System, but which appear common in the Galaxy. Given that some super-Earths are rocky, while others retain substantial atmospheres, their study can provide clues as to the formation of both rocky planets and gaseous planets, and -in particular -they can help to constrain the role of photo-evaporation in sculpting the exoplanet population. GJ 9827 is a system already known to host 3 super-Earths with orbital periods of 1.2, 3.6 and 6.2 days. Here we use new HARPS-N radial velocity measurements, together with previously published radial velocities, to better constrain the properties of the GJ 9827 planets. Our analysis can't place a strong constraint on the mass of GJ 9827 c, but does indicate that GJ 9827 b is rocky with a composition that is probably similar to that of the Earth, while GJ 9827 d almost certainly retains a volatile envelope. Therefore, GJ 9827 hosts planets on either side of the radius gap that appears to divide super-Earths into pre-dominantly rocky ones that have radii below ∼ 1.5R ⊕ , and ones that still retain a substantial atmosphere and/or volatile components, and have radii above ∼ 2R ⊕ . That the less heavily irradiated of the 3 planets still retains an atmosphere, may indicate that photoevaporation has played a key role in the evolution of the planets in this system.

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“…Given V and J magnitudes of 9.52 (Zacharias et al 2013) and 5.449±0.027 (Cutri et al 2003) we obtain a mass of 0.36 by also applying the relation of Delfosse et al (2000). According to Houdebine et al (2016) the star has a radius of 0.436±0.049 R ⊙ and effective temperature of 3414±100 K. Neves et al (2012) estimate the metallicity of AD Leo to be [Fe/H] = 0.07 and Royas- Ayala et al (2013) give a value of 0.28±0.17.…”

Section: Ad Leomentioning

confidence: 99%

Section: Ad Leomentioning

confidence: 99%

“…The estimated v sin i of AD Leo is 2.63 kms −1 (Houdebine et al 2016). Together with a radius estimate of 0.436±0.049, Houdebine et al (2016) then calculated a projected rotation period of 8.38 +1.2 −1.1 days. Thus, because the rotation period of the star is 2.23 days, this implies inclination of the rotation axis of 15.5 • +2.5 −2.0 , which means that the star is oriented nearly pole-on.…”

Section: Ad Leomentioning

confidence: 99%

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AD Leonis: Radial Velocity Signal of Stellar Rotation or Spin–Orbit Resonance?

Tuomi

Jones

Barnes

et al. 2018

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AD Leonis is a nearby magnetically active M dwarf. We find Doppler variability with a period of 2.23 days as well as photometric signals: (1) a short period signal which is similar to the radial velocity signal albeit with considerable variability; and (2) a long term activity cycle of 4070±120 days. We examine the short-term photometric signal in the available ASAS and MOST photometry and find that the signal is not consistently present and varies considerably as a function of time. This signal undergoes a phase change of roughly 0.8 rad when considering the first and second halves of the MOST data set which are separated in median time by 3.38 days. In contrast, the Doppler signal is stable in the combined HARPS and HIRES radial velocities for over 4700 days and does not appear to vary in time in amplitude, phase, period or as a function of extracted wavelength. We consider a variety of star-spot scenarios and find it challenging to simultaneously explain the rapidly varying photometric signal and the stable radial velocity signal as being caused by starspots co-rotating on the stellar surface. This suggests that the origin of the Doppler periodicity might be the gravitational tug of a planet orbiting the star in spin-orbit resonance. For such a scenario and no spin-orbit misalignment, the measured v sin i indicates an inclination angle of 15.5±2.5 deg and a planetary companion mass of 0.237±0.047 M Jup .

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ROTATION–ACTIVITY CORRELATIONS IN K AND M DWARFS. I. STELLAR PARAMETERS AND COMPILATIONS OF v sin i AND P/sin i FOR A LARGE SAMPLE OF LATE-K AND M DWARFS*

Cited by 46 publications

References 91 publications

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets

AD Leonis: Radial Velocity Signal of Stellar Rotation or Spin–Orbit Resonance?

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