J/ApJ/843/31 MUSCLES Treasury Survey. IV. M dwarf UV fluxes (Youngblood+, 2017)
The MUSCLES Treasury Survey.
IV. Scaling relations for ultraviolet, CaII K, and energetic particle fluxes
from M dwarfs.
Youngblood A., France K., Loyd R.O.P., Brown A., Mason J.P., Schneider P.C.,
Tilley M.A., Berta-Thompson Z.K., Buccino A., Froning C.S., Hawley S.L.,
Linsky J., Mauas P.J.D., Redfield S., Kowalski A., Miguel Y., Newton E.R.,
Rugheimer S., Segura A., Roberge A., Vieytes M.
<Astrophys. J., 843, 31 (2017)>
=2017ApJ...843...31Y 2017ApJ...843...31Y
ADC_Keywords: Stars, M-type ; Spectra, ultraviolet ; Spectra, optical ;
Equivalent widths
Keywords: stars: chromospheres ; stars: low-mass ; Sun: flares
Abstract:
Characterizing the UV spectral energy distribution (SED) of an
exoplanet host star is critically important for assessing its planet's
potential habitability, particularly for M dwarfs, as they are prime
targets for current and near-term exoplanet characterization efforts
and atmospheric models predict that their UV radiation can produce
photochemistry on habitable zone planets different from that on Earth.
To derive ground-based proxies for UV emission for use when Hubble
Space Telescope (HST) observations are unavailable, we have assembled
a sample of 15 early to mid-M dwarfs observed by HST and compared
their nonsimultaneous UV and optical spectra. We find that the
equivalent width of the chromospheric Ca II K line at 3933Å, when
corrected for spectral type, can be used to estimate the stellar
surface flux in ultraviolet emission lines, including HI Lyα. In
addition, we address another potential driver of habitability:
energetic particle fluxes associated with flares. We present a new
technique for estimating soft X-ray and >10MeV proton flux during
far-UV emission line flares (Si IV and He II) by assuming solar-like
energy partitions. We analyze several flares from the M4 dwarf GJ 876
observed with HST and Chandra as part of the MUSCLES Treasury Survey
and find that habitable zone planets orbiting GJ 876 are impacted by
large Carrington-like flares with peak soft X-ray fluxes ≥10-3W/m2
and possible proton fluxes ∼102-103pfu, approximately four orders
of magnitude more frequently than modern-day Earth.
Description:
We selected stars with HST UV spectra and ground-based optical spectra
either obtained directly by us or available in the VLT/XSHOOTER or
Keck/HIRES public archives.
Several targets have spectroscopic data obtained with the Dual Imaging
Spectrograph (DIS) on the ARC 3.5m telescope at Apache Point
Observatory (APO), R∼2500, or the REOSC echelle spectrograph on the
2.15m telescope at Complejo Astronomico El Leoncito (CASLEO), R∼12000,
within a day or two of the HST observations. We also gathered spectra
of GJ1132, GJ1214, and Proxima Cen on the nights of 2016 March 7-9
using the MIKE echelle spectrograph on the Magellan Clay telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 15 The M dwarf sample
table3.dat 189 15 UV emission line fluxes of the M dwarf sample
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See also:
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
J/A+AS/125/149 : CHIANTI - Atomic Database For Emission Lines I. (Dere+ 1997)
J/A+A/326/249 : Chromospheric models of dwarf M stars (Mauas+ 1997)
J/A+A/414/699 : Spectra of southern late-type dwarfs (Cincunegui+, 2004)
J/ApJ/634/625 : Radial velocities and photometry of GJ 876 (Rivera+, 2005)
J/A+A/469/309 : Chromospheric activity in late-type stars (Cincunegui+, 2007)
J/ApJ/736/12 : Transit light curves of GJ1214 (Berta+, 2011)
J/ApJ/728/48 : Multicolor eclipse data for 6 new binaries (Kraus+, 2011)
J/ApJ/761/166 : Terrestrial exoplanet atmospheres. I. (Hu+, 2012)
J/AJ/143/134 : Cand. members of β Pic / AB Dor groups (McCarthy+, 2012)
J/ApJS/211/9 : Variability in UV line emission of F-M stars (Loyd+, 2014)
J/AJ/148/64 : HAZMAT I. FUV & NUV emission in early M stars (Shkolnik+, 2014)
J/ApJ/807/45 : Potentially habitable planets around M dwarfs (Dressing+, 2015)
J/ApJ/812/3 : MEarth mid-to-late M dwarfs rotation & kinematics (West+, 2015)
J/ApJ/822/97 : Rotation-Activity relations in K-M dwarfs. (Houdebine+, 2016)
http://archive.stsci.edu/prepds/muscles/ : MUSCLES Treasury Survey on MAST
http://casa.colorado.edu/~ayres/StarCAT/ : HST STIS Echelle Spectral Catalog
of Stars (StarCAT)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Running number used in this paper
4- 14 A11 --- Name Star name
16- 16 A1 --- Exo [*] *: stars with known exoplanets
18- 21 F4.1 pc Dist [1.3/14.6] Distance
23- 23 A1 --- r_Dist [a-e] Reference for Dist (1)
25- 28 F4.2 Rsun Rad [0.1/0.9] Radius
30- 33 A4 --- r_Rad Reference(s) for Rad (1)
35- 40 A6 --- SpT Spectral Type
42- 44 A3 --- r_SpT Reference(s) for SpT (1)
46- 49 I4 K Teff [2820/3680] Effective temperature (2)
51- 51 A1 --- r_Teff Reference for Teff (1)
53- 53 A1 --- l_Prot Limit flag on Prot
54- 59 F6.2 d Prot [2.2/132.5]? Rotational period (2)
61- 61 A1 --- r_Prot Reference for Prot (1)
63- 67 F5.2 0.1nm EWCaK [0.3/21.3] Equivalent Width, Ca II K line
69- 72 F4.2 0.1nm e_EWCaK [0.01/6] Uncertainty in EWCaK
74- 79 F6.3 0.1nm EWCaKc [0.04/11.5] Corrected EW Ca II K line
81- 85 F5.3 0.1nm e_EWCaKc [0.005/2.1] Uncertainty in EWCaKc
87- 93 A7 --- Inst Source(s) for EWCaK measurements (3)
95- 98 I4 --- NCaK [1/351] Number of Ca II K spectra
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Note (1): References as follows:
a = van Leeuwen (2007A&A...474..653V 2007A&A...474..653V, I/311);
b = Anglada-Escude et al. (2013A&A...551A..48A 2013A&A...551A..48A);
c = Jenkins (1952gcsr.book.....J 1952gcsr.book.....J);
d = Lurie et al. (2014AJ....148...91L 2014AJ....148...91L);
e = Jao et al. (2005AJ....129.1954J 2005AJ....129.1954J);
f = Houdebine et al. (2016, J/ApJ/822/97);
g = von Braun et al. (2014MNRAS.438.2413V 2014MNRAS.438.2413V), interferometric measurement;
h = von Braun et al. (2011ApJ...729L..26V 2011ApJ...729L..26V), interferometric measurement;
i = von Braun et al. (2012ApJ...753..171V 2012ApJ...753..171V), interferometric measurement;
j = Kraus et al. (2011, J/ApJ/728/48);
k = Berta et al. (2011, J/ApJ/736/12);
l = Demory et al. (2009A&A...505..205D 2009A&A...505..205D), interferometric measurement;
m = White et al. (2015AAS...22534812W), interferometric measurement;
n = Berta-Thompson et al. (2015Natur.527..204B 2015Natur.527..204B);
o = Neves et al. (2014A&A...568A.121N 2014A&A...568A.121N);
p = McCarthy & White (2012, J/AJ/143/134);
q = Suarez Mascareno et al. (2015MNRAS.452.2745S 2015MNRAS.452.2745S);
r = Rivera et al. (2005, J/ApJ/634/625);
s = Robertson et al. (2015ApJ...805L..22R 2015ApJ...805L..22R);
t = Newton et al. (2016ApJ...821L..19N 2016ApJ...821L..19N);
u = Hunt-Walker et al. (2012PASP..124..545H 2012PASP..124..545H);
v = Roizman (1984SvAL...10..116R 1984SvAL...10..116R);
w = Benedict et al. (1998AJ....116..429B 1998AJ....116..429B);
x = Vogt et al. (1983ApJ...269..250V 1983ApJ...269..250V);
y = Pettersen (1980AJ.....85..871P 1980AJ.....85..871P);
z = Henry et al. (1994AJ....108.1437H 1994AJ....108.1437H);
aa = Hawley et al. (1996AJ....112.2799H 1996AJ....112.2799H, III/198).
Note (2): Rotation period (Prot) uncertainties are typically <10% and
effective temperature (Teff) uncertainties are typically ±100-200K
unless determined from interferometry (then ±20-100K). We have
rounded all Teff values to the nearest 10K.
Note (3): Source for EWCaK measurements as follows:
H = Keck/HIRES;
X = VLT/XSHOOTER;
R = CASLEO/REOSC;
D = APO/DIS;
M = Magellan/MIKE.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq Running number used in this paper
4- 14 A11 --- Name Star name
16- 16 A1 --- Exo [*] *: stars with known exoplanets
18- 18 A1 --- Ref Flux sources (4)
20- 27 E8.2 mW/m2 SiIII ? SiIII emission line flux, erg/cm2/s
29- 36 E8.2 mW/m2 e_SiIII ? Uncertainty in SiIII
38- 45 E8.2 mW/m2 LyA ? LyA emission line flux, erg/cm2/s (5)
47- 54 E8.2 mW/m2 e_LyA ? Uncertainty in LyA (5)
56- 63 E8.2 mW/m2 SiII ? SiII emission line flux, erg/cm2/s
65- 72 E8.2 mW/m2 e_SiII ? Uncertainty in SiII
74- 81 E8.2 mW/m2 CII ? CII emission line flux, erg/cm2/s
83- 90 E8.2 mW/m2 e_CII ? Uncertainty in CII
92- 99 E8.2 mW/m2 MgII ? MgII emission line flux, erg/cm2/s
101-108 E8.2 mW/m2 e_MgII ? Uncertainty in MgII
110-117 E8.2 mW/m2 SiIV ? SiIV emission line flux, erg/cm2/s
119-126 E8.2 mW/m2 e_SiIV ? Uncertainty in SiIV
128-135 E8.2 mW/m2 HeII ? HeII emission line flux, erg/cm2/s
137-144 E8.2 mW/m2 e_HeII ? Uncertainty in HeII
146-153 E8.2 mW/m2 CIV ? CIV emission line flux, erg/cm2/s
155-162 E8.2 mW/m2 e_CIV ? Uncertainty in CIV
164-171 E8.2 mW/m2 NV ? NV emission line flux, erg/cm2/s
173-180 E8.2 mW/m2 e_NV ? Uncertainty in NV
182-189 E8.2 mW/m2 EUV ? EUV flux, erg/cm2/s (6)
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Note (4): All emission line fluxes are as observed from Earth (erg/cm2/s).
Sources for the flux measurements as follows:
Y = Stars 1-7 come from Youngblood et al. (2016ApJ...824..101Y 2016ApJ...824..101Y) and
France et al. (2016ApJ...820...89F 2016ApJ...820...89F);
T = Stars 10, 12-15 are entirely from this work;
M = Stars where the flux measurements come from this work except for
individual lines for following stars--
AD Leo: MgII from Wood et al. (2005ApJS..159..118W 2005ApJS..159..118W);
EV Lac: Lyα from Wood et al. (2005ApJS..159..118W 2005ApJS..159..118W);
AU Mic: MgII from Wood+ (2005ApJS..159..118W 2005ApJS..159..118W), Lyα reconstructed
flux for AU Mic from Youngblood+ (2016ApJ...824..101Y 2016ApJ...824..101Y).
Note (5): Reconstructed Lyα fluxes. Asymmetric error bars from
Youngblood et al. (2016ApJ...824..101Y 2016ApJ...824..101Y) have been averaged.
Note (6): Calculated using the reconstructed Lyα fluxes and scaling
relations from Linsky+ (2014ApJ...780...61L 2014ApJ...780...61L), which have been
reprinted in Table 7.
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History:
From electronic version of the journal
References:
France et al. Paper I. 2016ApJ...820...89F 2016ApJ...820...89F
Youngblood et al. Paper II. 2016ApJ...824..101Y 2016ApJ...824..101Y
Loyd et al. Paper III. 2016ApJ...824..102L 2016ApJ...824..102L
Youngblood et al. Paper IV. 2017ApJ...843...31Y 2017ApJ...843...31Y This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Feb-2018