J/ApJ/794/146 M dwarfs with IR excess (Theissen+, 2014)
Warm dust around cool stars:
field M dwarfs with WISE 12 or 22µm excess emission.
Theissen C.A., West A.A.
<Astrophys. J., 794, 146 (2014)>
=2014ApJ...794..146T 2014ApJ...794..146T
ADC_Keywords: Stars, dwarfs ; Stars, M-type ; Models ; Equivalent widths ;
Effective temperatures ; Photometry, infrared
Keywords: circumstellar matter - infrared: stars - planet-disk interactions -
stars: low-mass
Abstract:
Using the Sloan Digital Sky Survey Data Release 7 (SDSS DR7)
spectroscopic catalog, we searched the WISE AllWISE catalog to
investigate the occurrence of warm dust, as inferred from IR excesses,
around field M dwarfs (dMs). We developed SDSS/WISE color selection
criteria to identify 175 dMs (from 70841) that show IR flux greater
than the typical dM photosphere levels at 12 and/or 22µm,
including seven new stars within the Orion OB1 footprint. We
characterize the dust populations inferred from each IR excess and
investigate the possibility that these excesses could arise from
ultracool binary companions by modeling combined spectral energy
distributions. Our observed IR fluxes are greater than levels expected
from ultracool companions (>3σ). We also estimate that the
probability the observed IR excesses are due to chance alignments with
extragalactic sources is <0.1%. Using SDSS spectra we measure surface
gravity-dependent features (K, Na, and CaH 3) and find <15% of our
sample indicates low surface gravities. Examining tracers of youth
(Hα, UV fluxes, and Li absorption), we find <3% of our sample
appear young, indicating we are observing a population of field stars
≳1Gyr, likely harboring circumstellar material. We investigate
age-dependent properties probed by this sample, studying the disk
fraction as a function of Galactic height. The fraction remains small
and constant to |Z|∼700pc and then drops, indicating little to no
trend with age. Possible explanations for disks around field dMs
include (1) collisions of planetary bodies, (2) tidal disruption of
planetary bodies, or (3) failed planet formation.
Description:
Parameters for 175 M dwarf stars showing signs of infrared excess.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 604 175 Parameters 175 M dwarfs
catalog.fits 2880 44 FITS version of the catalog
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See also:
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/AJ/145/52 : Abundances of late K and M dwarfs in binary systems (Mann+, 2013)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/175] Sequential number (CATALOG_NUMBER)
5- 22 I18 --- objID SDSS DR7 objID (SDSS_OBJID)
24- 32 F9.5 deg RAdeg Right ascension (J2000) (RA)
34- 42 F9.5 deg DEdeg Declination (J2000.0) (DEC)
44- 45 I2 --- SpT [0/10] M dwarf spectral type (dM_SpT) (1)
47- 54 F8.6 --- TiO5 [0/1.1] TiO5 spectral index (TIO5)
56- 63 F8.6 --- CaH3 [0.4/1] CaH3 spectral index (CAH3)
65- 72 F8.6 --- e_TiO5 [0/0.21]?=0 rms uncertainty on TiO5 (TIO5ERR)
74- 81 F8.6 --- e_CaH3 [0/0.17]?=0 rms uncertainty on CaH3 (CAH3ERR)
83- 91 F9.4 pc Dist0 [49/1500] Photometric distance, assuming AV=0
(DIST)
93-100 F8.6 mag AV [0/3.2] AV extinction measurement (2)
102-109 F8.6 mag e_AV [0/0.6] rms uncertainty on AV (AV_ERR)
111-118 F8.4 pc e_Dist [1/117] rms uncertainty on Dist (NEWDISTERR)
120-128 F9.4 pc Dist [49/1600] Extinction corrected
photometric distance (NEW_DIST)
130-136 F7.5 --- RVd [2.1/5.5]?=0 Dust radial velocity (DUSTRV)
138-144 F7.5 --- e_RVd [0.02/1.93]?=0 rms uncertainty on RVd
(DUSTRV_ERR)
146-154 F9.5 [Sun] [Fe/H] [-5.5/1.4]?=-99 Abundance [Fe/H] (FEH)
156-164 F9.5 [Sun] e_[Fe/H] ?=-99 rms uncertainty on [Fe/H] (FEH_ERR)
166-174 F9.5 [Sun] [M/H] [-1.1/0.7]?=-99 Abundance [M/H] (MH)
176-184 F9.5 [Sun] e_[M/H] ?=-99 rms uncertainty on [M/H] (MH_ERR)
186-193 F8.6 mag col1 [0.7/4.5] Color 1 index (COLOR1) (3)
195-203 F9.6 mJy S12 [0.2/16] Measured WISE/W3 12um flux density
(MEASURED12)
205-212 F8.6 mJy S12M [0.01/1] Model WISE 12um flux density
(PREDICTED12)
214-222 F9.6 mJy S22 [0.9/48] Measured WISE/W4 22um flux density
(MEASURED22)
224-231 F8.6 mJy S22M [0/0.3] Model WISE 22um flux density
(PREDICTED22)
233-242 F10.5 km/s e_RV [1/553]?=-999 rms uncertainty on RV (RV_ERR)
244-253 F10.5 km/s RV [-137/232] Radial velocity
255-259 I5 K TeffM [2400/4000] Model effective temperature of star
(MODEL_TEMP)
261-269 F9.6 [Sun] [M/H]M [-2.5/0] Model [M/H] (MODEL_MH)
271-273 F3.1 [cm/s2] loggM [0.5/6] Model surface gravity (MODEL_LOGG)
275-282 F8.6 Lsun Lum [0.0004/0.13] Luminosity (LUMINOSITY)
284-295 E12.6 Lsun e_Lum rms uncertainty on Luminosity (LUMINOSITY_ERR)
297-304 F8.6 Rsun R [0.07/0.83] Radius (RADIUS)
306-313 F8.6 Rsun e_R rms uncertainty on R (RADIUS_ERR)
315-319 I5 K Td [125/325]?=-9999 Disk temperature (DISK_TEMP)
321-328 F8.6 --- Lir [0/1.002] Fractional IR luminosity
(FRAC_LUMINOSITY)
330-341 E12.6 --- Md Dust mass, in moon mass unit (DUST_MASS)
343-350 F8.6 AU Rd [0.01/1.51] dust radius (DUST_RADIUS)
352-359 F8.5 0.1nm W8200 ?=-9 Na 8200 equivalent width (EWNA8200)
361-368 F8.5 0.1nm e_W8200 ?=-9 rms uncertainty on W8200 (EWNA8200ERR)
370-378 F9.5 --- s_W8200 [7/80]?=-99 Na 8200 equivalent width S/N
(NA8200SNR)
380-387 F8.5 0.1nm W7665 ?=-9 KI 7665 equivalent width (EWKI7665)
389-396 F8.5 0.1nm e_W7665 ?=-9 rms uncertainty on W7665 (EWKI7665ERR)
398-405 F8.5 0.1nm W7699 ?=-9 KI 7699 equivalent width (EWKI7699)
407-414 F8.5 0.1nm e_W7699 ?=-9 rms uncertainty on W7699 (EWKI7699ERR)
416-424 F9.5 0.1nm W.KI ?=-99 KI total equivalent width (EWKITOT)
426-433 F8.5 0.1nm e_W.KI ?=-9 rms uncertainty on W.KI (EWKITOTERR)
435-444 F10.5 --- s_W7665 ?=-999 KI 7665 equivalent width S/N (KI7665SNR)
446-455 F10.5 --- s_W7699 ?=-999 KI 7699 equivalent width S/N (KI7699SNR)
457-466 F10.5 0.1nm W.Ha ?=-999 Hα equivalent width (HALPHA)
468-477 F10.5 0.1nm e_W.Ha ?=-999 rms uncertainty on W.Ha (HALPHAERR)
479-487 F9.6 --- s_W.Ha Hα equivalent width S/N (HALPHASNR)
490-498 F9.5 0.1nm W.CaK ?=-99 CaIIK equivalent width (CAIIK)
500-508 F9.5 0.1nm e_W.CaK ?=-99 rms uncertainty on EWCaIIK (CAIIKERR)
510-519 F10.6 --- s_W.CaK [-2/35] CaIIK equivalent width S/N (CAIIKSNR)
521-522 I2 --- A.Ha [0/1]?=-9 Hα activity flag (HALPHAACT)
524-525 I2 --- A.Ca [0/1]?=-9 CaIIK activity flag (CAIIKACT)
527-530 I04 --- Youth [0/1111] Youth flag (YOUTH) (4)
532-542 F11.5 km/s U ?=-9999 U velocity
544-554 F11.5 km/s V ?=-9999 V velocity
556-566 F11.5 km/s W ?=-9999 W velocity
568-578 F11.5 km/s e_U ?=-9999 rms uncertainty on U (U_ERR)
580-590 F11.5 km/s e_V ?=-9999 rms uncertainty on V (V_ERR)
592-602 F11.5 km/s e_W ?=-9999 rms uncertainty on W (W_ERR)
604 I1 --- Q [1/4] Quality flag, 1=best (QUALITY) (5)
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Note (1): Some parameters taken from West et al., 2011AJ....141...97W 2011AJ....141...97W,
Cat. J/AJ/141/97
Note (2): Some parameters taken from Jones et al., 2011AJ....142...44J 2011AJ....142...44J.
Note (3): Spectrosocopic index Color 1, used to compute the [M/H] values
and defined in Hawley et al. (2002AJ....123.3409H 2002AJ....123.3409H).
Note (4): Youth flag is a 4 digit code, with 0 for no, 1 for yes, for
* Hα emission
* low surface gravity in at least two of the three tracers
* lithium absorption
* UV activity
Note (5): Quality 1 representing the highest-quality candidates and
quality 4 representing the lowest-quality candidates.
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Acknowledgements:
Christopher A. Theissen, ctheisse(at)bu.edu
References:
Wast et al., 2011AJ....141...97W 2011AJ....141...97W, Cat. J/AJ/141/97
Jones et al., 2011AJ....142...44J 2011AJ....142...44J,
Mann et al., 2013AJ....145...52M 2013AJ....145...52M, Cat. J/AJ/145/52
(End) Patricia Vannier [CDS] 15-Apr-2015