20 years of the HKProject: Long-term activity in cool stars
Andrea Buccino
FEEPA Stellar Physics, Exoplanets and
Astrobiology HKProject Past and Present Staff
Pablo Mauass C. Cincunegui Rodrigo Díaz Andrea Buccino M. Luisa Luoni
M. Vieytes R. Petrucci C. Martinez
Grupo de Física Estelar,
Exoplanetas y Astrobiología FEEPA Matías Floress Romina Ibañez Bustos OutlineOutline
1. Our interests on M stars.
2. HK Project -Description -Results
3. New issues in solar-type stars.
-The Pcyc-Prot diagram (again) -HK contribution
WhyWhy dMdM stars?stars?
1. Easy to detect terrestrial habitable planets around them.
2.Remarkable short-term variations in stellar luminosity due to flares.
3. Mean magnetic field; type of dynamo could change over this stellar class.
HighHigh ocurrenceocurrence ofof terrestrialterrestrial planetsplanets aroundaround dMdM starsstars
Kepler
Near 2.5 planets per M dwarf with radii 1−4 R⊕ and periods shorter than 200 days.
Near 0.16 Earth-size planets and near 0.12 super-Earths per M dwarf HZ.
RV
Super-Earths 36% with P = 1−10 d and 52% for P = 10−100 d around M stars.
(Dressing and Charbonneau, 2015, ApJ, 807, 45) (Bonfils et al, 2013, A&A, 549, 109) Trappist Planetary system
WhyWhy dMdM stars?stars?
1. Easy to detect terrestrial habitable planets around them.
2.Remarkable short-term variations in stellar luminosity due to flares.
3. Mean magnetic field: type of dynamo could change over this stellar class.
FlareFlare activityactivity
Hawley et al. (2014, ApJ, 797, 922) Light Curve of GJ 1243 (M4V). Over 6100 individual flare events, 29 33 with energies ranging from 10 to 10 erg, are found in 11 months of 1 minute cadence data from Kepler (~18 flares per day). FlareFlare activityactivity
Hawley et al. (2014, ApJ, 797, 121)
M dwarfs span a large range of flarefrequency and energy, blurring the distinction between active and inactive stars designated solely by the presence of Hα. Hawley et al. (2014) found a strong correlations between flare energy, amplitude, duration, and decay time, with only a weak dependence on rise time. Habitable terrestrial planets?
WhyWhy dMdM stars?stars?
1. Easy to detect terrestrial habitable planets around them.
2.Remarkable short-term variations in stellar luminosity due to flares.
3. Mean magnetic field: type of dynamo could change over this stellar class.
WhyWhy dMdM stars?stars?
1. Easy to detect terrestrial habitable planets around them
2.Remarkable short-term variations in stellar luminosity due to flares
3. Mean magnetic field; type of dynamo could change over this stellar class
Solar dynamo
Stellar interior
The role of the solar tacochline seems to be fundamental to strength magnetic field and avoid its dissipation
Stellar interior
The role of the solar tacochline seems to be fundamental to strength magnetic field and avoid its dissipation
<0.35 MSol 0.35-1.5 MSol >1.5 MSol
Stellar interior
The role of the solar tacochline seems to be fundamental to strength magnetic field and avoid its dissipation
<0.35 MSol 0.35-1.5 MSol >1.5 MSol ¿Stellar activity without tacochline ? Listening to observations
West et al (2004, AJ, 128, 426)
Active stars beyond the threshold M3.5
Does the magnetic topology change beyond the convection boundary?
Efficiency of convection to generate Moutou et al (2017, MNRAS, 472, 4563) Strong poloidal large-scale magnetic fields
Magnetic activity without tacochline
Wright and Drake (2016, Nature, 535, 526)
“The lack of a tachocline in fully convective stars suggests that this is not a critical ingredient in the solar dynamo and supports models in which the dynamo originates throughout the convection zone.”
HKProject
HKProject
Complejo Astronómico El Leoncito IAU Observatory Code: 829 (OC) λ = -69°17’44”.1 φ = -31°47’54”.7 h = 2552 msnm UT-offset = -3 hs url: casleo.conicet.gov.ar HKProject Jorge Sahade Sistema óptico: Reflector Ritchey-Chrètien Fabricante: Boller & Chivens telescope Montura: Tipo horquilla
Datos ópticos principales Diámetro del espejo primario: 2153 mm Razón focal Cassegrain: 8.485 Escala: 11.3 ''/mm Escala con Reductor: 33.9 ''/mm Diámetro del espejo secundario (Cassegrain): 660.3 mm Diámetro del agujero del primario: 635 mm Emergencia: 965 mm Distancia focal primario: 5588 mm Distancia focal secundario (Cassegrain): 2215 mm Peso del espejo primario: 1315 kg Peso del espejo secundario (Cassegrain): 71.7
REOSC Spectrograph
Características del CCD filas × columnas 1024 × 1024 ruido de lectura (gain 1) 0.4 e- tamaño del pixel 24 × 24 µm ruido de lectura (gain 4) 7.4 e- dimensiones del chip 25 mm × 25 mm corriente oscura 0.4 e-/hora/pixel ganancia 1 7.97 e-/ADU temperatura de trabajo -120 °C ganancia 4 1.98 e-/ADU
HKProject Main Goals
To build an atlas of flux calibrated reliable spectra of southern FGKM active stars to employ them in semiempircal atmospheric models.
To explore long-term activity near the convective limit (~M3.5V).
Registry of simultaneous activity indicators of different stellar atmospheric depth ( eg. H, Ca II).
Grupo de Física Estelar, Exoplanetas y Astrobiología FEEPA HKProject
20 years of continuously observations since 1999, 4 observing runs a year.
Near 5500 mid-res optical spectra (R=13000) calibrated in flux of near 150 F3V a M5.5V stars.
Wavelength range from 3800 to 7000 A, which allows us to observe simultaneously different features formed at the high, mid and low chromosphere.
One of the few program mainly dedicated to follow stellar activity of dwarf stars which lasted more than 16 years.
Cincunegui y Mauas (2004, A&A, 414, 699) HKProject- Stellar Sample
HKProject- Stellar Sample
FGK
FGKM
HKProject vs. HARPS Sample
140 stars
Lovis et al. (2011, astro-ph)
Centered on active stars Centered on inactive stars Stellar activity indices from HKProjectspectra
Stellar activity indices from HKProjectspectra Na I- Díaz et al (2007)! H-Cincunegui et al (2007)? Ca II -Mount Wilson
HKProject
1.Cincunegui et al (2007, A&A, 469, 309) H - Ca II H+K is not unique for individual stars
2. Metcalfe, Buccino, Brown et al. (2013, ApJL,763, 29) Two precise activity cycles for Eridani (K2V) of 12 and 3 years. 3. Cincunegui et al (2007, A&A, 414, 699) A 442-day activity cycle in M5.5Ve Proxima Centauri First activity cycle in a dM star + purely convective star
4. Buccino et al (2011, AJ,141, 34) Activity cycles in early dM stars GJ 229 A (4 years) y GJ 752 A (7 years) 5. Díaz et al (2007, A&A, 474, 345) 800-day activity cycle of the two components of the binary system GJ 375 (M3.5V+M3.5V) Magnetic interaction?
HKProject
1.Cincunegui et al (2007, A&A, 469, 309) H - Ca II H+K is not unique for individual stars
2. Metcalfe, Buccino, Brown et al. (2013, ApJL,763, 29) Two precise activity cycles for Eridani (K2V) of 12 and 3 years. F i r s t
3. Cincunegui et al (2007, A&A, 414, 699) A A 442-day activity cycle in M5.5Ve Proxima Centauri c t i First activity cycle in a dM star + purely convective star v i t y
C
4. Buccino et al (2011, AJ,141, 34) y Activity cycles in early dM stars GJ 229 A (4 years) y GJ 752 A (7 years) c l e s
i 5. Díaz et al (2007, A&A, 474, 345) n
800-day activity cycle of the two components of the binary system GJ 375 (M3.5V+M3.5V) d Magnetic interaction? M
s
t a r s
First results of HK Project
442 day-chromospherric cycle for M5.5Ve Proxima Centauri Great impact: fist detection of activity cycle in M stars + activity cycle in a fully convective star (no tachocline)
Cincunegui et al (2007, A&A, 414, 699)
New cycles of Proxima Centauri
Recently a 7-year cycle detected from spectra and ASAS.
Wargelin et al (2017, MNRAS, 464, 3281)
Preliminary new results of Proxima Centauri HK Project
Two activity cycles of 1.1 years and 6.3 years.
PhD thesis of Romina Ibañez Bustos
GJ 375 A+B (M3.5V+3.5V) GJ 229 A (M1/2V) P ~ 4 years Pcyc~763 days cyc
Díaz et et al. (2007, A&A,474,345 ) GGJ 752 A (M2.5V) Pcyc~ 7 years
AD Leo (M3.5V) Pcyc~ 8 years
Buccino et al. (2011, AJ, 141,34)
Buccino et al. (2014, ApJ, 781, L9) AU Microscopii
Young (25 Myr) Early M star
Fast-rotator (Prot~ 4.85 days)
AU Microscopii
Ibañez Bustos et al. (2019, MNRAS, 483, 1159) GJ 447-Ross 128
Slow Rotator
(Prot~110-120 days) Fully convective (M4V) Terrestrial Exoplanet (habitable?)
GJ 447-Ross 128
Ibañez Bustos et al. (2019, A&A, 628, L1) Magnetic activity vs. rotation period AD AU Leo Mic
GL 752A
Ross 128 Astudillo-Defru et a. (2017, A&A, 600, 13)
Ross 128 becomes one of the few slow-rotator stars of its class outside the saturation regime to present a stellar activity cycle.
New perspective for HKProject CONCH-SHELL catalog
All-sky catalogue of 2970 nearby (d ≲ 50 pc), bright (J < 9) M- or late K-type dwarf stars, 86 per cent of which have been confirmed by spectroscopy.
Ideal catalogue to search Earth-size and Super-Earth size planets. They are included in CARMENES and TESS sample.
New perspective for HKProject CONCH-SHELL sample
First conclusion
Fast, slow-rotators, early, partially or fully convective dM stars present stellar activity cycles similar to the solar-type stars. Similar dynamo?
We are working on expanding the sample and on building 2D non-linear dynamo models.
Epsilon Eridani -HD 22049 (K2V)
Metcalfe, Buccino, Brown et al. (2013, ApJL,763, 29)
Epsilon Eridani -HD 22049 (K2V)
Metcalfe, Buccino, Brown et al. (2013, ApJL,763, 29)
Epsilon Eridani -HD 22049 (K2V)
45 years span Two simultaneous activity cycles of 3 and 13 years. Broad minimum between 1985 an 1992.
Metcalfe, Buccino, Brown et al. (2013, ApJL,763, 29) Is the solar dynamo in trasition?
Metcalfe et al. (2016, ApJL,826, 5pp) .
Given its position in the diagram Pcyc-Prot , the Sun seems to be in a transitional phase.
Metcalfe et al (2017) sustain that also other stars with Ro~2 evolved as the Sun does now, they suggest tha the solar cycle could disappear between 0.8-2.4 Gyr Iota Horologii -HD 17051 (F8V)
Sanz Forcada et al. (2013, A&A, 553, L6)
Active young star (625 Myr)
hosting an exoplanet 2.25 MJ a 0.925 AU.
Short activity cycle of 1.6 yr with an irregular amplitude which suggested that a longer 5-6 yr cycle modulated the short one.
Iota Horologii -HD 17051 (F8V) NOT dM star
Flores, Buccino, Saffe, Mauas (2017, MNRAS, 464, 4299)
Mount Wilson from CASLEO and HARPS spectra agree over 10 years.
Long-term activity cycle of 4.6 year of irregular amplitude.
Sun in transition?
Metcalfe et al. (2016, ApJL,826, 5pp)
Hor
A simple dynamo modelo for Eridani
Non-linear axisymetric dynamo developed Sraibman & Minotti (2019). Surface differential rotation profile of Eridani measured by Croll et al. (2006) en surface and internal structure from astrosismology by Gai et al. (2016). An activity proxy from the dynamo model of Eridani
From the analysis of the IB index with periodograms, we obtained a ~4 and ~11-year cycle, similar to the 3 and 12-year cycle reported in Metcalfe et al. (2013).
Second conclusion
Simultaneous activity cycles in solar-type stars could be modeled by a typical dynamo similar to the solar one.
Main conclusion (Invitation)
Let’s join our observations to get reliable cycles.
casleo.conicet.gov.ar
Thank you
@buccinito [email protected]
New perspective for HKProject CONCH-SHELL catalog
ID Sp Type and class
PMI 16554-0819 M3V
Echelle CASLEO spectra of this sample already obtained. (Romina Ibañez Bustos thesis)
PMI 17131-1834 M2V
PMI 18554+0824 M3V
PMI 18498-2350 M3.5V
PMI20045-2342 M4V
PMI 21490-7206 M1V
PMI22387-2037 M2V
PMI20418-3226 M4V
PMI17286-4653 M3V
PMI14111-6155 M2V
PM5200 I12378- M3V
PMI12234-2309 K7V