Precision radial velocities of 15 M5-M9 dwarfs

J. R. Barnes, J. S. Jenkins, H. R.A. Jones, S. V. Jeffers, P. Rojo, P. Arriagada, A. Jordán, D. Minniti, M. Tuomi, D. Pinfield, G. Anglada-Escudé

Resultado de la investigación: Article

24 Citas (Scopus)

Resumen

We present radial velocity measurements of a sample ofM5V-M9Vstars from our Red-Optical Planet Survey, operating at 0.652-1.025 μm. Radial velocities for 15 stars, with rms precision down to 2.5m-1 over a week-long time-scale, are achieved using thorium-argon reference spectra. We are sensitive to planets with mp sin i ≥ 1.5M (3M at 2σ) in the classical habitable zone, and our observations currently rule out planets with mp sini ≥ 0.5MJ at 0.03 au for all our targets. A total of 9 of the 15 targets exhibit rms<16m-1, which enables us to rule out the presence of planets with mp sini > 10M in 0.03 au orbits. Since the mean rotation velocity is of the order of 8 km-1 for an M6V star and 15 km -1 for M9V, we avoid observing only slow rotators that would introduce a bias towards low axial inclination (i< 90°) systems, which are unfavourable for planet detection. Our targets with the highest v sin i values exhibit radial velocities significantly above the photon-noise-limited precision, even after accounting for v sin i. We have therefore monitored stellar activity via chromospheric emission from the Hα and Ca II infrared triplet lines. A clear trend of log10(L/Lbol) with radial velocity rms is seen, implying that significant starspot activity is responsible for the observed radial velocity precision floor. The implication that most late M dwarfs are significantly spotted, and hence exhibit time varying line distortions, indicates that observations to detect orbiting planets need strategies to reliablymitigate against the effects of activity-induced radial velocity variations.

Idioma originalEnglish
Páginas (desde-hasta)3094-3113
Número de páginas20
PublicaciónMonthly Notices of the Royal Astronomical Society
Volumen439
N.º3
DOI
EstadoPublished - 1 ene 2014

Huella dactilar

radial velocity
planets
planet
planet detection
starspots
stellar activity
stars
thorium
velocity measurement
inclination
argon
orbits
trends
timescale
photons

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Barnes, J. R., Jenkins, J. S., Jones, H. R. A., Jeffers, S. V., Rojo, P., Arriagada, P., ... Anglada-Escudé, G. (2014). Precision radial velocities of 15 M5-M9 dwarfs. Monthly Notices of the Royal Astronomical Society, 439(3), 3094-3113. https://doi.org/10.1093/mnras/stu172
Barnes, J. R. ; Jenkins, J. S. ; Jones, H. R.A. ; Jeffers, S. V. ; Rojo, P. ; Arriagada, P. ; Jordán, A. ; Minniti, D. ; Tuomi, M. ; Pinfield, D. ; Anglada-Escudé, G. / Precision radial velocities of 15 M5-M9 dwarfs. En: Monthly Notices of the Royal Astronomical Society. 2014 ; Vol. 439, N.º 3. pp. 3094-3113.
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abstract = "We present radial velocity measurements of a sample ofM5V-M9Vstars from our Red-Optical Planet Survey, operating at 0.652-1.025 μm. Radial velocities for 15 stars, with rms precision down to 2.5m-1 over a week-long time-scale, are achieved using thorium-argon reference spectra. We are sensitive to planets with mp sin i ≥ 1.5M⊕ (3M⊕ at 2σ) in the classical habitable zone, and our observations currently rule out planets with mp sini ≥ 0.5MJ at 0.03 au for all our targets. A total of 9 of the 15 targets exhibit rms<16m-1, which enables us to rule out the presence of planets with mp sini > 10M⊕ in 0.03 au orbits. Since the mean rotation velocity is of the order of 8 km-1 for an M6V star and 15 km -1 for M9V, we avoid observing only slow rotators that would introduce a bias towards low axial inclination (i< 90°) systems, which are unfavourable for planet detection. Our targets with the highest v sin i values exhibit radial velocities significantly above the photon-noise-limited precision, even after accounting for v sin i. We have therefore monitored stellar activity via chromospheric emission from the Hα and Ca II infrared triplet lines. A clear trend of log10(LHα/Lbol) with radial velocity rms is seen, implying that significant starspot activity is responsible for the observed radial velocity precision floor. The implication that most late M dwarfs are significantly spotted, and hence exhibit time varying line distortions, indicates that observations to detect orbiting planets need strategies to reliablymitigate against the effects of activity-induced radial velocity variations.",
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Barnes, JR, Jenkins, JS, Jones, HRA, Jeffers, SV, Rojo, P, Arriagada, P, Jordán, A, Minniti, D, Tuomi, M, Pinfield, D & Anglada-Escudé, G 2014, 'Precision radial velocities of 15 M5-M9 dwarfs', Monthly Notices of the Royal Astronomical Society, vol. 439, n.º 3, pp. 3094-3113. https://doi.org/10.1093/mnras/stu172

Precision radial velocities of 15 M5-M9 dwarfs. / Barnes, J. R.; Jenkins, J. S.; Jones, H. R.A.; Jeffers, S. V.; Rojo, P.; Arriagada, P.; Jordán, A.; Minniti, D.; Tuomi, M.; Pinfield, D.; Anglada-Escudé, G.

En: Monthly Notices of the Royal Astronomical Society, Vol. 439, N.º 3, 01.01.2014, p. 3094-3113.

Resultado de la investigación: Article

TY - JOUR

T1 - Precision radial velocities of 15 M5-M9 dwarfs

AU - Barnes, J. R.

AU - Jenkins, J. S.

AU - Jones, H. R.A.

AU - Jeffers, S. V.

AU - Rojo, P.

AU - Arriagada, P.

AU - Jordán, A.

AU - Minniti, D.

AU - Tuomi, M.

AU - Pinfield, D.

AU - Anglada-Escudé, G.

PY - 2014/1/1

Y1 - 2014/1/1

N2 - We present radial velocity measurements of a sample ofM5V-M9Vstars from our Red-Optical Planet Survey, operating at 0.652-1.025 μm. Radial velocities for 15 stars, with rms precision down to 2.5m-1 over a week-long time-scale, are achieved using thorium-argon reference spectra. We are sensitive to planets with mp sin i ≥ 1.5M⊕ (3M⊕ at 2σ) in the classical habitable zone, and our observations currently rule out planets with mp sini ≥ 0.5MJ at 0.03 au for all our targets. A total of 9 of the 15 targets exhibit rms<16m-1, which enables us to rule out the presence of planets with mp sini > 10M⊕ in 0.03 au orbits. Since the mean rotation velocity is of the order of 8 km-1 for an M6V star and 15 km -1 for M9V, we avoid observing only slow rotators that would introduce a bias towards low axial inclination (i< 90°) systems, which are unfavourable for planet detection. Our targets with the highest v sin i values exhibit radial velocities significantly above the photon-noise-limited precision, even after accounting for v sin i. We have therefore monitored stellar activity via chromospheric emission from the Hα and Ca II infrared triplet lines. A clear trend of log10(LHα/Lbol) with radial velocity rms is seen, implying that significant starspot activity is responsible for the observed radial velocity precision floor. The implication that most late M dwarfs are significantly spotted, and hence exhibit time varying line distortions, indicates that observations to detect orbiting planets need strategies to reliablymitigate against the effects of activity-induced radial velocity variations.

AB - We present radial velocity measurements of a sample ofM5V-M9Vstars from our Red-Optical Planet Survey, operating at 0.652-1.025 μm. Radial velocities for 15 stars, with rms precision down to 2.5m-1 over a week-long time-scale, are achieved using thorium-argon reference spectra. We are sensitive to planets with mp sin i ≥ 1.5M⊕ (3M⊕ at 2σ) in the classical habitable zone, and our observations currently rule out planets with mp sini ≥ 0.5MJ at 0.03 au for all our targets. A total of 9 of the 15 targets exhibit rms<16m-1, which enables us to rule out the presence of planets with mp sini > 10M⊕ in 0.03 au orbits. Since the mean rotation velocity is of the order of 8 km-1 for an M6V star and 15 km -1 for M9V, we avoid observing only slow rotators that would introduce a bias towards low axial inclination (i< 90°) systems, which are unfavourable for planet detection. Our targets with the highest v sin i values exhibit radial velocities significantly above the photon-noise-limited precision, even after accounting for v sin i. We have therefore monitored stellar activity via chromospheric emission from the Hα and Ca II infrared triplet lines. A clear trend of log10(LHα/Lbol) with radial velocity rms is seen, implying that significant starspot activity is responsible for the observed radial velocity precision floor. The implication that most late M dwarfs are significantly spotted, and hence exhibit time varying line distortions, indicates that observations to detect orbiting planets need strategies to reliablymitigate against the effects of activity-induced radial velocity variations.

KW - Planetary systems

KW - Planets and satellites: detection

KW - Stars: activity

KW - Stars: atmospheres

KW - Stars: low-Mass

KW - Techniques: radial velocities

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U2 - 10.1093/mnras/stu172

DO - 10.1093/mnras/stu172

M3 - Article

AN - SCOPUS:84896471807

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SP - 3094

EP - 3113

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

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Barnes JR, Jenkins JS, Jones HRA, Jeffers SV, Rojo P, Arriagada P y otros. Precision radial velocities of 15 M5-M9 dwarfs. Monthly Notices of the Royal Astronomical Society. 2014 ene 1;439(3):3094-3113. https://doi.org/10.1093/mnras/stu172