J/AJ/155/196 Analysis of K2 LCs for members of USco & ρ Oph (Rebull+, 2018)
Rotation of low-mass stars in Upper Scorpius and ρ Ophiuchus with K2.
Rebull L.M., Stauffer J.R., Cody A.M., Hillenbrand L.A., David T.J.,
Pinsonneault M.
<Astron. J., 155, 196 (2018)>
=2018AJ....155..196R 2018AJ....155..196R (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Stars, pre-main sequence ; Photometry ;
Optical ; Photometry, infrared
Keywords: stars: low-mass - stars: pre-main sequence
Abstract:
We present an analysis of K2 light curves (LCs) for candidate members
of the young Upper Sco (USco) association (∼8 Myr) and the neighboring
ρ Oph embedded cluster (∼1 Myr). We establish ∼1300 stars as probable
members, ∼80% of which are periodic. The phased LCs have a variety of
shapes which can be attributed to physical causes ranging from stellar
pulsation and stellar rotation to disk-related phenomena. We identify
and discuss a number of observed behaviors. The periods are ∼0.2-30 days
with a peak near 2 days and the rapid period end nearing breakup velocity.
M stars in the young USco region rotate systematically faster than
GK stars, a pattern also present in K2 data for the older Pleiades and
Praesepe systems. At higher masses (types FGK), the well-defined
period-color relationship for slowly rotating stars seen in the Pleiades
and Praesepe systems is not yet present in USco. Circumstellar disks
are present predominantly among the more slowly rotating M stars in USco,
with few disks in the subday rotators. However, M dwarfs with disks rotate
faster on average than FGK systems with disks. For four of these disked
M dwarfs, we provide direct evidence for disk locking based on the K2 LC
morphologies. Our preliminary analysis shows a relatively mass-independent
spin-up by a factor of ∼3.5 between USco and the Pleiades, then
mass-dependent spin-down between Pleiades and Praesepe.
Description:
USco and ρ Oph were observed in K2 Campaign 2, from 2014 August 23
to 2014 November 13 (82 days). There are 2631 objects with K2 LCs that
have been claimed to be candidate members of USco or ρ Oph.
For each target, we selected the best LC from up to three different
available LC versions: (1) a version with moving apertures with magnitudes
computed for several different aperture sizes, using custom software
developed by co-author Cody; (2) the "self-flat-fielding" approach used
by Vanderburg & Johnson (2014PASP..126..948V 2014PASP..126..948V) and the K2SFF pipeline
as obtained from MAST, the Mikulski Archive for Space Telescopes; and (3)
the LCs from the EVEREST2 pipeline (Luger et al. 2016AJ....152..100L 2016AJ....152..100L,
2018AJ....156...99L 2018AJ....156...99L), which uses pixel-level decorrelation, as obtained
from MAST.
To assemble additional, uniform photometry, we queried many all-sky or
large-scale surveys, including the Gaia DR1 release (Gaia
Collaboration et al. 2016, Cat. I/337) for their G magnitudes and the APASS
database (Henden et al. 2016, Cat. II/336), particularly for V magnitudes.
For more optical data, we queried the recently released Pan-STARRS1
database (Chambers et al. 2016, Cat. II/349) and the Sloan Digital Sky
Survey (SDSS; e.g., Ahn et al. 2014ApJS..211...17A 2014ApJS..211...17A). We added to this
infrared data from the Two Micron All Sky Survey (2MASS; Skrutskie et al.
2006, Cat. VII/233) and the Deep Near-Infrared Southern Sky Survey
(DENIS; Foque & Bertin 1995ApL&C..31...31F 1995ApL&C..31...31F).
Objects:
-----------------------------------------------------------------------
RA (ICRS) DE Designation(s)
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16 12 -23.4 Upper Scorpius = NAME Upper Sco Association
16 26 22 -24 23.7 ρ Ophiuchus= NAME rho Oph IR Cluster
-----------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 219 1313 Periods and supporting data for USco and ρ Oph
members with K2 light curves
table3.dat 219 1313 Periods and supporting data for USco and ρ Oph
non-members with K2 light curves
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See also:
II/240 : The DENIS database first release (Epchtein+, 1999)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
J/AJ/120/479 : Low-mass stars in the Upper Sco association (Ardila+, 2000)
J/AJ/121/1040 : PMS members of upper Scorpius OB association
(Preibisch+, 2001)
J/AJ/124/404 : Upper Scorpius OB association Lithium survey. II.
(Preibisch, 2002)
J/ApJ/630/381 : Mid-IR imaging in ρ Oph (Barsony+, 2005)
J/AJ/131/3016 : Low-mass objects in Upper Scorpius (Slesnick+, 2006)
J/ApJ/651/L49 : Upper Sco OB association IRAC observations
(Carpenter+, 2006)
J/ApJ/688/377 : Low-mass objects in Upper Scorpius. II. (Slesnick+, 2008)
J/ApJ/705/1646 : Debris disks in Upper Sco (Carpenter+, 2009)
J/A+A/527/A24 : Spectra of low-mass stars in Upper Sco (Lodieu+, 2011)
J/AJ/142/140 : Optical spectroscopy of ρ Oph stars. II.
(Erickson+, 2011)
J/ApJ/758/31 : IR photometry for members of Upper Sco (Luhman+, 2012)
J/MNRAS/448/2737 : New PMS K/M Stars in Upper Scorpius (Rizzuto+, 2015)
J/AJ/152/113 : Pleiades members with K2 light curves. I. Periods
(Rebull+, 2016)
J/AJ/152/114 : Pleiades members with K2 light curves. II. (Rebull+, 2016)
J/AJ/152/115 : Pleiades members with K2 light curves. III.
(Stauffer+, 2016)
J/AJ/154/256 : VLM stars and BDs in Upper Sco using Gaia DR1 (Cook+, 2017)
J/ApJ/839/92 : Praesepe members with K2 light curve data (Rebull+, 2017)
Byte-by-byte Description of file: table1.dat table3.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- EPIC [202499459/210282557] Ecliptic Plane Input
Catalog identifier
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 33 F4.1 arcsec DEs Arcsecond of Declination (J2000)
35- 63 A29 --- OName Other identifier
65- 69 F5.2 mag Vmag [4.57/19.1]? Apparent V band Vega magnitude
71- 75 F5.2 mag Ksmag [2.24/16.75]? Apparent Ks band Vega magnitude
77- 81 F5.2 mag (V-Ks)o [-0.41/16.75]? Directly observed (V-Ks) color
83- 87 F5.2 mag (V-Ks)u [-0.41/18.3]? The (V-Ks) color used (1)
89- 93 F5.2 mag E(V-Ks) [0/36.36]? Adopted (V-Ks) color excess
(see Section 2.4)
95- 99 F5.2 mag Ksmag0 [2.1/16.66]? Dereddened Ks band Vega
magnitude
101-105 F5.2 mag (V-Ks)0 [-1.03/9.8]? Dereddened (V-Ks) color (2)
107-108 I2 --- n_(V-Ks) [-9/6] Note on (V-Ks) (3)
110-111 I2 --- n_(V-Ks)0 [-9/3] Note on (V-Ks)0 (4)
113-119 F7.4 d Per1 [0.0476/38.3933]? Primary period (taken to be
the rotation period, see text)
121-127 F7.4 d Per2 [0.0458/23.9255]? Secondary period
129-135 F7.4 d Per3 [0.045/12.9722]? Tertiary period
137-143 F7.4 d Per4 [0.0452/18.3921]? Quaternary period
145-155 A11 --- Memb Membership (not in Table 3) (5)
157-161 A5 --- Disk IR excess (disk) is present? (maybe, yes or no)
163-172 A10 um DStart Wavelength of start of IR excess (6)
174-176 A3 --- Dip [yes ] Light curve matches dipper
characteristics? (not in Table 3) (7)
178-180 A3 --- Burst [yes ] Light curve matches burster
characteristics? (not in Table 3) (7)
182-187 A6 --- Multi Single or multi-period star
189-191 A3 --- DD [yes no] Double-dip light curve? (8)
193-195 A3 --- DDmove [yes no] Moving double-dip light curve? (8)
197-199 A3 --- Shch [yes no] Shape changer? (8)
201-203 A3 --- Beat [yes no] Full light curve has beating visible?
(8)
205-207 A3 --- CPeak [yes no] Complex peak? (8) (9)
209-211 A3 --- RClose [yes no] Resolved close periods? (8)
213-215 A3 --- RDist [yes no] Resolved distant periods? (8)
217-219 A3 --- Pulse [yes no] Pulsator? (8)
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Note (1): Observed or inferred; see text.
Note (2): See Section 2.4; rounded to nearest 0.1 to emphasize the relatively
low accuracy.
Note (3): Digit denoting origin of (V-Ks) defined as follows (see Sections
2.2 and 2.4):
1 = V measured directly from the literature (including SIMBAD) and Ks from
2MASS;
2 = V from APASS and Ks from 2MASS;
3 = (V-Ks) inferred from Gaia G and Ks from 2MASS (see Section 2.2);
4 = (V-Ks) inferred from Pan-STARRS1 g and Ks from 2MASS
(see Section 2.2);
5 = (V-Ks) inferred from membership work (see Section 2.3; rare);
6 = V inferred from well-populated optical SED and Ks from 2MASS
(see Section 2.2);
-9 = No measure of (V-Ks).
Note (4): Digit denoting origin of E(V-Ks) leading to (V-Ks)0 defined as
follows (see Sections 2.2 and 2.4):
1 = Dereddening from JHKs diagram (see Section 2.4);
2 = Dereddening back to (V-Ks)0 expected for spectral type;
3 = Used median E(V-Ks)=0.7 (see Section 2.4);
-9 = No measure of E(V-Ks).
Note (5): USco gold, silver, bronze, or ROph gold, silver, bronze,
see Section 2.3 and Appendix A.
Note (6): Where IR excess starts or the limit of our knowledge of where there
is no excess, see Section 4.
Note (7): See Section 3.2.4.
Note (8): See Section 6.2 and Appendix Section E.
Note (9): Power spectrum has a complex, structured peak and/or has a wide peak.
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History:
From electronic version of the journal
References :
Rebull et al., Paper I. 2016AJ....152..113R 2016AJ....152..113R, Cat. J/AJ/152/113
Rebull et al., Paper II. 2016AJ....152..114R 2016AJ....152..114R, Cat. J/AJ/152/114
Stauffer et al., Paper III. 2016AJ....152..115S 2016AJ....152..115S, Cat. J/AJ/152/115
Rebull et al., Paper IV. 2017ApJ...839...92R 2017ApJ...839...92R, Cat. J/ApJ/839/92
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 30-Nov-2018