J/AJ/156/217 Stellar properties for M dwarfs in MEarth-South (Newton+, 2018)
New rotation period measurements for M dwarfs in the southern hemisphere:
an abundance of slowly rotating, fully convective stars.
Newton E.R., Mondrik N., Irwin J., Winters J.G., Charbonneau D.
<Astron. J., 156, 217-217 (2018)>
=2018AJ....156..217N 2018AJ....156..217N (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Stars, dwarfs ; Stars, M-type ; Proper motions ;
Parallaxes, trigonometric ; Stars, distances ; Radial velocities ;
Stars, diameters ; Stars, masses
Keywords: stars: individual: Proxima Centauri, Wolf 359, GJ 1286 -
stars: low-mass - stars: rotation
Abstract:
Stellar rotation periods are valuable both for constraining models of
angular momentum loss and for understanding how magnetic features impact
inferences of exoplanet parameters. Building on our previous work in
the northern hemisphere, we have used long-term, ground-based photometric
monitoring from the MEarth Observatory to measure 234 rotation periods
for nearby, southern hemisphere M dwarfs. Notable examples include the
exoplanet hosts GJ 1132, LHS 1140, and Proxima Centauri. We find excellent
agreement between our data and K2 photometry for the overlapping subset.
Among the sample of stars with the highest quality data sets, we recover
periods in 66%; as the length of the data set increases, our recovery rate
approaches 100%. The longest rotation periods we detect are around
140 days, which we suggest represent the periods that are reached when
M dwarfs are as old as the local thick disk (about 9 Gyr).
Description:
The MEarth Project is an all-sky survey of approximately 3000 nearby,
predominantly mid-to-late M dwarfs (Berta et al. 2012AJ....144..145B 2012AJ....144..145B;
Irwin et al. 2015csss...18..767I 2015csss...18..767I). Like MEarth-North, MEarth-South
comprises eight 40 cm telescopes on German Equatorial Mounts, equipped
with CCD cameras. These telescopes are housed in a roll-off roof at
Cerro Tololo Inter-American Observatory (CTIO) in Chile. Exposure times
are set independently for each star based on the S/N required to detect
small planets. We use a maximum exposure time of 75 s, so this S/N is
achieved by coadding individual exposures. Multiple exposures are also
obtained for bright targets in order to average over scintillation noise.
We term one set of coadded exposures a visit. There are typically between
1 and 25 visits per night, per target. The MEarth-South survey is ongoing;
the analysis presented here uses data obtained prior to BJD 2458179.5
(12am 2018 March 2 UT). We analyze data from 574 stars from MEarth-South.
Objects:
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RA (ICRS) DE Designation(s)
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14 29 42.95 -62 40 46.2 Proxima Centauri = 2MASS J14294291-6240465
10 56 28.83 +07 00 52.3 Wolf 359 = 2MASS J10562886+0700527
23 35 10.46 -02 23 20.6 GJ 1286 = 2MASS J23351050-0223214
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 203 574 Rotation periods and stellar properties for all
rotators and non-detections in MEarth-South
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See also:
J/ApJ/812/3 : MEarth mid-to-late M dwarfs rotation + kinematics (West+, 2015)
J/ApJ/818/153 : MEarth photometry: nearby M-dwarf magnitudes (Dittmann+, 2016)
J/AJ/156/140 : Four new eclipsing mid M-dwarf systems from MEarth
(Irwin+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Type [ABNU] Source type (1)
3- 18 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
20- 29 A10 --- LSPM LSPM identifier (JHHMM+DDMM)
31- 40 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
42- 53 F12.8 deg DEdeg Declination in decimal degrees (J2000)
55- 63 F9.4 arcsec/yr pmRA [-998.635/32.7596] Proper motion along RA
65- 71 F7.4 arcsec/yr pmDE [-2.8905/1.115] Proper motion along DE
73- 78 F6.4 arcsec plx [0.0272/0.7687]? Parallax
80- 85 F6.4 arcsec e_plx [0.0003/0.03]? Uncertainty in plx
87-105 A19 --- r_plx ADS bibliography code reference for plx
107-111 F5.2 pc Dist [1.3/38.4] Adopted distance
113-118 F6.1 km/s RV [-141.9/77.6]? Radial velocity
120-123 F4.1 km/s e_RV [0.1/40]? Uncertainty in RV
125-143 A19 --- r_RV ADS bibliography code reference for RV
145-151 F7.3 d Per [0.129/225.16]? Photometric rotation period
153-158 F6.4 mag Amp [0.0009/0.5567]? Semi-amplitude of
variability
160-165 F6.4 mag e_Amp [0/1.6207]? Uncertainty in Amp
167-171 F5.3 Msun M* [0.074/0.526] Stellar mass
173-177 F5.3 Rsun R* [0.137/0.498] Stellar radius
179 I1 --- Flag [1]? Contamination flag (2)
181-185 I5 --- NPts [2/18597]? Number of data points in longest
dataset with a successful fit
187-189 I3 --- NDays [1/745] Number of days in longest dataset
191-196 F6.4 mag magerr [0.0011/0.0188] Median photometric error
198-203 I6 --- F-test [0/328225]? F-test statistic
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Note (1): Source type as follows:
A = Grade A rotators;
B = Grade B rotators;
U = Possible or uncertain detection;
N = Non-detection or undetermined detection.
Note (2): Flag as follows:
1 = Indicating known contamination by a common proper motion companion or
background source.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 03-Apr-2019