Addressing stellar activity at every step in the RV follow-up of small planets. Raphaëlle D. Haywood. Stellar activity or Earth-mass planet?

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1 Addressing stellar activity at every step in the RV follow-up of small planets Stellar activity or Earth-mass planet? Raphaëlle D. Haywood and the GTO Science Team NASA Sagan Fellow, Harvard College Observatory Image credit: Natalie Cameron

2 Stellar activity-induced RV variations are quasi-periodic RVs of the Sun as a star

3 Stellar activity-induced RV variations are quasi-periodic RVs of the Sun as a star Stellar rotation period

4 Stellar activity-induced RV variations are quasi-periodic RVs of the Sun as a star Active-region lifetime Stellar rotation period

5 Towards robust mass determinations for small planets We need to know about the temporal magnetic behaviour of our host stars

6 Towards robust mass determinations for small planets We need to know about the temporal magnetic behaviour of our host stars See next talk by Helen Giles!

7 Towards robust mass determinations for small planets We need to know about the temporal magnetic behaviour of our host stars See next talk by Helen Giles! Sample planet orbit and stellar activity strategically

8 Towards robust mass determinations for small planets We need to know about the temporal magnetic behaviour of our host stars See next talk by Helen Giles! Sample planet orbit and stellar activity strategically Account for both uncorrelated and correlated noise in RV analysis

9 Kepler-21 Porb: 2.7 days 1.6 R F6 slightly evolved Prot: 12 days V=8.25 mag

10 Kepler-21 Porb: 2.7 days 1.6 R F6 slightly evolved Prot: 12 days V=8.25 mag HIRES

11 Kepler-21 Mass estimate from HIRES only: mp < 10M Howell et al. (2012) Porb: 2.7 days 1.6 R F6 slightly evolved Prot: 12 days V=8.25 mag HIRES

12 Kepler-21 Mass estimate from HIRES only: mp < 10M Howell et al. (2012) Porb: 2.7 days 1.6 R F6 slightly evolved Prot: 12 days V=8.25 mag HIRES mp = 5.1 ± 1.7 M (3-sigma significance) López-Morales, Haywood, Giles et al. (2016)

13 HIRES López-Morales, Haywood, Giles et al. (2016)

14 HIRES López-Morales, Haywood, Giles et al. (2016)

15 HIRES Orbital period López-Morales, Haywood, Giles et al. (2016)

16 HIRES Orbital period Rotation period López-Morales, Haywood, Giles et al. (2016)

17 HIRES Orbital period Rotation period López-Morales, Haywood, Giles et al. (2016)

18 HIRES Orbital period Rotation period Active-region lifetime López-Morales, Haywood, Giles et al. (2016)

19 HIRES Orbital period Rotation period Active-region lifetime López-Morales, Haywood, Giles et al. (2016)

20 HIRES Orbital period Rotation period Active-region lifetime 28 obs. over 15 nights We sampled the rotation period within the active-region lifetime López-Morales, Haywood, Giles et al. (2016)

21 Accounting for stellar activity in our mass determination K-21 b López-Morales, Haywood, Giles et al. (2016)

22 Accounting for stellar activity in our mass determination jitter term For uncorrelated noise: granulation, poorly-sampled stellar activity + Gaussian process regression (quasi-periodic kernel) Correlated noise: well-sampled stellar activity K-21 b López-Morales, Haywood, Giles et al. (2016) See also Haywood et al. (2014), Grunblatt et al. (2015), Rajpaul et al. (2015), Faria et al. (2016), Barros et al. (2017) and others

23 Proxima Centauri b Anglada-Escudé et al. (2016) Detection of a 1.3 M planet in an 11-day orbit around an active M dwarf HARPS UVES

24 Proxima Centauri b Anglada-Escudé et al. (2016) Detection of a 1.3 M planet in an 11-day orbit around an active M dwarf HARPS UVES Less than 3 months!

25 Towards robust mass determinations for small planets We need to know about the temporal magnetic behaviour of our host stars Sample planet orbit and stellar activity strategically Account for both uncorrelated and correlated noise in RV analysis