MUSCLES: Spectra of M & K Exoplanet Host Stars from the X-ray and Ultraviolet to the Infrared

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MUSCLES Treasury Survey - Spectra of M & K Exoplanet Host Stars
from the X-ray and Ultraviolet to the Infrared

PI: Kevin France (Colorado)
MUSCLES Series:
MUSCLES Paper I - France et al. 2016, ApJ, 820, 89	MUSCLES Paper IV - Youngblood et al. 2017, ApJ, 843, 31
MUSCLES Paper II - Youngblood et al. 2016, ApJ, 824, 101	MUSCLES Paper V - Loyd et al. ApJ, submitted
MUSCLES Paper III - Loyd et al. 2016, ApJ, 824, 102
Semi-Empirical Synthetic Models:
Fontenla et al. 2016, ApJ, 830, 154

Introduction	Data Products	Data Access	Plot Scripts	README (TXT) (PDF)
Acknowledgement: If you make use of the MUSCLES spectral data products, please cite Papers I, II, and III from the top of this page and specify the version number of the spectra you used in your work. The version number is in the filenames. For example, "v22" denotes version 2.2. If you use the semi-empirical synthetic models, please cite the relevant paper(s) in the "Semi-Empirical Synthetic Models" section at the top of the page.

Introduction

MUSCLES is a spectral survey of 11 low-mass, planet-hosting stars, 7 M and 4 K dwarfs. The spectra cover wavelengths from 5 Å to 5.5 µm, with emphasis on high-energy radiation. More information on the MUSCLES survey and collaboration can be found at the MUSCLES team page. Data sources for the various regions of the spectra are:

X-rays: Chandra/XMM-Newton and APEC models (Smith et al. 2001, ApJ, 556, 91)
EUV: Empirical scaling relation based on Lya flux (Linsky et al. 2014, ApJ, 780, 61)
Lya: Reconstructed from model fit to line wings (Youngblood et al., 2016, ApJ, 824, 101)
FUV - blue visible:: HST COS and STIS
Visible - IR: Synthetic photospheric spectra from PHOENIX atmosphere models (Husser et al. 2013, A&A, 553, 6)

The next generation of MUSCLES, Mega-MUSCLES, has begun observations that will roughly double this dataset and extend spectral type coverage to M8.

Data Products

The data products from each of the 11 stars are organized into subdirectories based on the star name. Several files are available for each target. We provide a brief summary below, for full details, consult the README file.

Primary Data Products

*const-res-sed.fits = Panchromatic SED binned to a constant 1 Å resolution. One file per star.
*var-res-sed.fits = Panchromatic SED that retains the native instrument resolutions where possible. One file per star.
*adapt-const-res-sed.fits = Panchromatic SED binned to a constant 1 Å resolution, downsampled in low signal-to-noise regions to avoid negative fluxes. One file per star.
*adapt-var-res-sed.fits = Panchromatic SED that retains the native instrument resolutions where possible, downsampled in low signal-to-noise regions to avoid negative fluxes. One file per star.

Ancillary Data Products

*hst_cos*component-spec.fits = Coadded HST COS spectrum. One file per observed grating (three for each star, except V-EPS-ERI, which has two).
*hst_stis*component-spec.fits = Coadded HST STIS spectrum. One file per observed grating (three for each star, except V-EPS-ERI, which has four).
*euv-scaling*component-spec.fits = Extreme UV spectrum based on empirical scaling relation using Lyα flux. One file per star.
*lya-reconstruction*component-spec.fits = Reconstructed spectrum from model fits to Lyα line profiles accounting for the stellar flux and the interstellar medium. One file per star.
*phx*component-spec.fits = Synthetic spectrum in the visible and infrared from PHOENIX models. One file per star.

Proxima Centauri (GJ 551)

In response to popular demand after the announcement of the discovery of a habitable-zone planet orbiting Prox Cen, we added Prox Cen to the MUSCLES sample and created an SED from archival data using methodology consistent with the other MUSCLES SEDs. We highly encourage users of the Prox Cen spectra to read these notes on the reduction of the Prox Cen spectra, as they address an important issue regarding the stellar effective temperature and bolometric flux.

Semi-Empirical Models (Jump To Data Access)

Also available for download is a synthetic spectrum of the MUSCLES M2 dwarf GJ 832 from Fontenla et al. 2016. The synthetic spectrum was created from a one-dimensional model of the stellar atmosphere that incorporates non-LTE radiative transfer techniques and many molecular lines. The synthetic spectrum covers 1 Å - 1 mm at a resolving power R = 100,000 (denoted by "r1e5" in the file names). A single resolution element equals two wavelength samples. For consistency with the MUSCLES data products, the synthetic spectrum's wavelength is in Angstroms and the flux is reported as would be observed from Earth (erg/cm2/s/Å) under the assumption that the stellar radius = 0.499 R_solar (Houdebine 2010) and distance = 4.95 pc (van Leeuwen 2007). Note that Houdebine et al. 2016 determine GJ 832's stellar radius to be 0.458 ± 0.039 R_solar. The atomic and molecular transitions appear at their laboratory rest wavelengths (vacuum). Semi-empirical models of the other 10 MUSCLES stars as well as Proxima Centauri and TRAPPIST-1 are coming soon. If you utilize the GJ 832 synthetic spectrum, please cite Fontenla et al. 2016, ApJ, 830, 154.

Data Access

Click on a star name to visit the Simbad page for that target. Download a .tar.gz containing all FITS files for a target using the (tar) link.
Click on "FITS" to directly download the FITS file. Click on "PL" to use the MAST interactive plotter.
Note: The STIS observations used a few different modes for a given central wavelength, e.g., the _140_ column contains spectra observed with either the G140M or E140M modes. In all cases, consult the FITS header and/or file name to get the full observation modes used for a given target.

Target	Panchromatic		X-Ray		EUV	Lyα	HST COS			HST STIS			PHX
	Const.	Var.	CXO\|XMM	APEC			G130M	G160M	G230L	_140_	_230_	_430_
GJ1214 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL		FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ176 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ436 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ581 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ667C (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ832 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
GJ832_SYNTH (tar) Adaptive Res. →
GJ876 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
HD40307 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
HD85512 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
HD97658 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS^† PL		FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL
V-EPS-ERI‡ (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL		FITS PL	FITS PL FITS PL	FITS PL	FITS PL
Target	Panchromatic		X-Ray		EUV	Lyα	HST FOS		HST STIS				PHX
	Const.	Var.	CXO\|XMM	APEC			G570H	G780H	_140_	_230_	_430_	_750_
GJ551 (tar) Adaptive Res. →	FITS PL FITS PL	FITS PL FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL

^† NOTE: The X-ray spectrum for HD 97658 does not come from XMM or Chandra observations. It is scaled from X-ray data of HD 85512, which shows similar lines in the UV. For more details, consult the README or primary publication.
^‡ NOTE: The links in the top row of the "_230_" cell are for the E230M data, while the links in the bottom row are for the E230H data.

Semi-Empirical Synthetic Spectra

Target	XRAY	EUV	FUV-NUV-VIS	MIR	FIR-SUBMM	ALL
	(1-100 Å)	(100-912 Å)	(912 Å - 2.5 μm)	(2.5 - 500 μm)	(500 μm - 1 mm)
	R = 100,000	R = 100,000	R = 100,000	R = 100,000	R = 100,000	R = 100,000
GJ 832	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL	FITS PL

Example Plot Scripts

The example file used here, hlsp_muscles_multi_multi_gj436_broadband_v10_adapt-const-res-sed.fits, can be downloaded by clicking the "FITS" link in the GJ 436 / Adaptive Res row under the Panchromatic / Const column.

Python:

from astropy.io import fits
import matplotlib.pyplot as plt
spec = fits.getdata('hlsp_muscles_multi_multi_gj436_broadband_v10_adapt-const-res-sed.fits',1)
plt.plot(spec['WAVELENGTH'],spec['FLUX'])
plt.xlabel('Wavelength (Angstroms)')
plt.ylabel('Flux Density (erg/cm2/s/Ang)')
plt.show()

IDL:

data_436 = MRDFITS(path+'hlsp_muscles_multi_multi_gj436_broadband_v10_adapt-const-res-sed.fits',$
                   1,head_436)
wave = data_436.wavelength
flux = data_436.flux
error = data_436.error
plot, wave, flux, xs=1, ys=1, xr=[10,50000], yr=[0.001,10000]*1d-15,$
      /ylog, /xlog, TITLE='GJ 436; MUSCLES Example',$
      xtitle='Wavelength (Ang)', ytitle='Observed Flux Density (erg/cm2/s/Ang)',$
      charsize=1.75

README (TXT) (PDF)

Proxima Centauri (GJ 551)

Semi-Empirical Models (Jump To Data Access)