J/ApJ/812/3 MEarth mid-to-late M dwarfs rotation & kinematics (West+, 2015)
An activity-rotation relationship and kinematic analysis of nearby
mid-to-late-type M dwarfs.
West A.A., Weisenburger K.L., Irwin J., Berta-Thompson Z.K.,
Charbonneau D., Dittmann J., Pineda J.S.
<Astrophys. J., 812, 3 (2015)>
=2015ApJ...812....3W 2015ApJ...812....3W (SIMBAD/NED BibCode)
ADC_Keywords: Proper motions ; Radial velocities ; Stars, distances ;
Equivalent widths ; Stars, M-type
Keywords: stars: activity; stars: chromospheres; stars: kinematics and dynamics
stars: late-type; stars: low-mass; stars: rotation
Abstract:
Using spectroscopic observations and photometric light curves of 238
nearby M dwarfs from the MEarth exoplanet transit survey, we examine
the relationships between magnetic activity (quantified by Hα
emission), rotation period, and stellar age. Previous attempts to
investigate the relationship between magnetic activity and rotation in
these stars were hampered by the limited number of M dwarfs with
measured rotation periods (and the fact that v sin i measurements
probe only rapid rotation). However, the photometric data from MEarth
allows us to probe a wide range of rotation periods for hundreds of M
dwarf stars (from shorter than one to longer than 100 days). Over all
M spectral types that we probe, we find that the presence of magnetic
activity is tied to rotation, including for late-type, fully
convective M dwarfs. We also find evidence that the fraction of
late-type M dwarfs that are active may be higher at longer rotation
periods compared to their early-type counterparts, with several
active, late-type, slowly rotating stars present in our sample.
Additionally, we find that all M dwarfs with rotation periods shorter
than 26 days (early-type; M1-M4) and 86 days (late-type; M5-M8) are
magnetically active. This potential mismatch suggests that the
physical mechanisms that connect stellar rotation to chromospheric
heating may be different in fully convective stars. A kinematic
analysis suggests that the magnetically active, rapidly rotating stars
are consistent with a kinematically young population, while
slow-rotators are less active or inactive and appear to belong to an
older, dynamically heated stellar population.
Description:
To measure M dwarf rotation periods, we use photometric observations
from the MEarth survey for transiting exoplanets (see Nutzman &
Charbonneau 2008PASP..120..317N 2008PASP..120..317N; Berta et al. 2012AJ....144..145B 2012AJ....144..145B).
All of the data in this paper come from the MEarth-north array at the
Fred Lawrence Whipple Observatory (FLWO) at Mt. Hopkins, AZ, which has
been gathering data since 2008.
FAST spectrograph (1.5m Tillinghast Telescope at FLWO, R=3000;
5550-7550Å) observations were acquired over 30 nights from 2010
December to 2012 July.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 286 238 Kinematics, activity, and rotation periods for
MEarth M dwarfs
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See also:
I/298 : LSPM-North Catalog (Lepine+ 2005)
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
J/ApJ/807/45 : Likely habitable planets around M dwarfs (Dressing+, 2015)
J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)
J/AJ/147/20 : Spectroscopy of 447 nearby M dwarfs (Newton+, 2014
J/MNRAS/432/1203 : Rotation periods of M-dwarf stars (McQuillan+, 2013))
J/A+A/557/L10 : Rotation periods of 12000 Kepler stars (Nielsen+, 2013)
J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)
J/AJ/144/93 : Close white dwarf + M dwarf binaries (WD+dM) (Morgan+, 2012)
J/ApJ/750/L37 : Stellar parameters of low-mass KOIs (Muirhead+, 2012)
J/ApJ/742/123 : Photometry and Velocity of LSPM J1112+7626 (Irwin+, 2011)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/ApJ/705/1416 : Volume-limited sample of M7-M9.5 dwarfs <20pc (Reiners+, 2009)
J/MNRAS/392/1456 : VIc photometry of M50 low-mass stars (Irwin+, 2009)
J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/AJ/134/2398 : Stellar SEDs in SDSS and 2MASS filters (Covey+, 2007)
J/AJ/129/2428 : M dwarf-white dwarf binary systems (Silvestri+, 2005)
J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/ApJS/141/503 : Radial Velocities for 889 late-type stars (Nidever+, 2002)
J/MNRAS/328/45 : Late-type stars members of young groups (Montes+, 2001)
J/A+A/331/581 : Rotation and activity in field M dwarfs (Delfosse+ 1998)
J/A+A/327/1039 : Structure and evolution of low-mass stars (Chabrier+ 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [LSPM]
5- 15 A11 --- LSPM M Dwarf identifier (JHHMM+DDMMW)
17- 18 I2 h RAh [0/23] Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 28 F6.3 s RAs Second of Right Ascension (J2000)
30 A1 --- DE- [+] Sign of the Declination (J2000)
31- 32 I2 deg DEd [0/83] Degree of Declination (J2000)
34- 35 I2 arcmin DEm Arcminute of Declination (J2000)
37- 41 F5.2 arcsec DEs Arcsecond of Declination (J2000)
43- 44 A2 --- SpT MK spectral type
46- 49 F4.1 pc Dist [5.4/65]? Distance
51 A1 --- f_Dist [DL] Flag on Dist (1)
53- 57 F5.1 km/s RVel [-90/84] Radial velocity
59- 63 I5 mas/yr pmRA [-1540/1749] Proper motion along RA (2)
65- 69 I5 mas/yr pmDE [-5123/591] Proper motion along DE (2)
71- 76 F6.2 km/s U [-49.1/58]? The U radial velocity (3)
78- 82 F5.2 km/s e_U ? Uncertainty in U
84- 89 F6.2 km/s V [-66.7/35]? The V tangential velocity (3)
91- 95 F5.2 km/s e_V ? Uncertainty in V
97-102 F6.2 km/s W [-36.1/54]? The W velocity perpendicular to
the plane (3)
104-108 F5.2 km/s e_W ? Uncertainty in W
110-117 F8.4 d Per [0.16/154.2]? Rotation period
119-124 F6.4 mag Amp [0.002/0.05]? Rotation semi-amplitude
126-134 A9 yr Season Rotation season
136-141 F6.2 0.1nm HaEW [0.7/29]? Hα equivalent width;
Angstroms (4)
143-147 F5.2 0.1nm e_HaEW [0.2/6.3]? Uncertainty in HaEW
149 I1 --- AFlag [0/1] Activity flag (1=active M dwarf,
0=Inactive M dwarf; see Section 3.1)
151 I1 --- RFlag [0/2] Rotation flag (5)
153-158 F6.3 [-] logL [-5.4/-3.1]? Log ratio of Hα to
bolometric luminosities
160-165 F6.4 --- TiO1 [0.5/1] The TiO1 molecular bandhead index (6)
167-172 F6.4 --- e_TiO1 Uncertainty in TiO1
174-179 F6.4 --- TiO2 [0.01/0.2] The TiO2 molecular bandhead index (6)
181-186 F6.4 --- e_TiO2 Uncertainty in TiO2
188-193 F6.4 --- TiO3 [0.4/0.9] The TiO3 molecular bandhead index (6)
195-200 F6.4 --- e_TiO3 Uncertainty in TiO3
202-207 F6.4 --- TiO4 [0.4/0.9] The TiO4 molecular bandhead index (6)
209-214 F6.4 --- e_TiO4 Uncertainty in TiO4
216-221 F6.4 --- TiO5 [0.2/0.7] The TiO5 molecular bandhead index (6)
223-228 F6.4 --- e_TiO5 Uncertainty in TiO5
230-235 F6.4 --- CaH2 [0.2/0.7] The CaH2 molecular bandhead index (6)
237-242 F6.4 --- e_CaH2 Uncertainty in CaH2
244-249 F6.4 --- CaH3 [0.5/0.9] The CaH3 molecular bandhead index (6)
251-256 F6.4 --- e_CaH3 Uncertainty in CaH3
258-263 F6.4 --- CaOH [0.1/0.7] The CaOH molecular bandhead index (6)
265-270 F6.4 --- e_CaOH Uncertainty in CaOH
272-279 F8.4 0.1nm NaI [-12/6] Na I absorption line equivalent width;
Angstroms
281-286 F6.4 0.1nm e_NaI Uncertainty in NaI
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Note (1): Flag as follows:
D = a trigonometric parallax measurement derived from MEarth imaging,
as published in Dittmann et al. (2014ApJ...784..156D 2014ApJ...784..156D).
L = distance comes from Lepine et al. (2005, Cat. I/298) and
may be either photometric, spectroscopic, or trigonometric.
Note (2): Proper motions are quoted as projected on the plane of the sky,
with (pmRA,pmDE)=(µRA*cosδ,µδ).
Note (3): Quoted in a right-handed coordinate system, with U pointed
towards the Galactic center.
Note (4): This table uses a convention in which emission lines correspond to
equivalent widths >0.
Note (5): Stars with measured rotation periods have a Rotation Flag value
of 1 or 2, with a value of 1 being more robust. Stars whose
rotation periods did not cross our detection threshold are
flagged as 0 (see Section 2.1).
Note (6): As defined in Reid et al. (1995, Cat. III/198).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Feb-2016