Mission Overview

Habitable Zones and M dwarf Activity across Time ("HAZMAT")

 

Primary Investigator: Evgenya Shkolnik

Co-Investigators: Travis Barman, R.O. Parke Loyd, Victoria S. Meadows, Isabella Pagano, Sarah Peacock, Tyler Richey-Yonwell, Adam C. Schneider

HLSP Authors: Sarah Peacock

Released: 2020-05-05

Updated: 2020-05-05

Primary Reference(s): Peacock et al. (2020)

DOI: 10.17909/t9-j6bz-5g89

Citations: See ADS Statistics

Read Me

Source Data:

Figure 1

A compilation of the results from HAZMAT I, III, V, and VI: median EUV (1 – 100 Angstroms, blue), FUV (1340 – 1810 Angstroms, red) and NUV (1687 – 3010 Angstroms, black) fractional fluxes as a function of age for M and K type stars. Low mass stars have increased levels of short wavelength emission that remain elevated for hundreds of millions of years while planets are forming their primary and, in some cases, secondary atmospheres.

Figure 2

The synthetic UV spectra of median 0.45 solar mass models at 120 Myr (orange), 650 Myr (blue), and 5 Gyr (purple). Prominent emission features and the wavelength ranges used to compute band integrated fluxes in HAZMAT Paper VI are labeled in the top panel. Spectral resolution has been degraded for clarity.

Table 1

Stellar parameters used for the models. The BHAC15 models (Baraffe et al. 2015) were used to obtain the values, taking a rounded average between 0.4 and 0.5 solar mass stars for the 0.45 solar mass models, and 0.3 and 0.4 solar mass stars for the 0.35 solar mass models.

Overview

The HAbitable Zones and M dwarf Activity across Time (HAZMAT) program assesses the lifetime exposure of planets to stellar ultraviolet (UV) radiation using GALEX data, HST COS and STIS spectra, and semi-empirical, full-wavelength models. The program quantifies the evolution of far- and near-UV (FUV; NUV) emission for early- and mid-M (HAZMAT I), late-M (HAZMAT III), and K (HAZMAT V) type stars, as well as extreme-UV (EUV) emission from early-M stars (HAZMAT VI).

The data products below are high-resolution synthetic spectra (EUV – IR; 100 Angstroms to 5.5 microns) of early-M stars at five distinct ages between 10 Myr and 5 Gyr. The spectra are computed with the PHOENIX atmosphere code from one-dimensional upper atmosphere models of 0.35 and 0.45 solar mass stars (stellar parameters given in Table 1 of the HAZMAT VI paper). The wavelengths (given in Angstroms) are in vacuum and the wavelength grid has a resolution of <0.1 Angstroms. The flux densities (given in ergs/cm^2/s/Angstrom) are that at the stellar surface and are scalable to a distance D via (R_star/D)^2 where R_star is dependent on the age and mass of the star from Table 1.

Downloadable data products include five spectra per 0.35 and 0.45 solar mass stars at ages of 10, 45, 120, 650, and 5000 Myr. The spectra reproduce either the minimum ("MIN"), lower quartile ("LQ"), median ("MED"), upper quartile ("UQ"), or maximum ("MAX") FUV and NUV flux density per age as calculated from the GALEX stellar sample in HAZMAT I.  The complete set of HAZMAT series papers are available in the Reference section at the bottom of the page.

Also available for download are high-resolution full-wavelength (100 Angstrom – 950 micron) PHOENIX spectra of specific M dwarf planet host stars from Peacock et al. 2019a,b. The data products are synthetic spectra in wavelength (Angstrom) and flux density at the surface of the star (ergs/s/cm^2/ Angstrom). In the publications, the flux densities are scaled by (R_star/D)^2.  The Peacock et al. 2019a,b references are available in the Reference section at the bottom of the page.

TRAPPIST-1 is a moderately active ultracool M8 dwarf star that hosts seven transiting planets orbiting within 0.063 au. In the absence of broadband UV spectral observations, we constrained three different models using HST Lyman α observations from TRAPPIST-1 (Model “1A”) and Galaxy Evolution Explorer UV photometric detections from a set of old (>1 Gyr) M8 stars (Models “2A” and “2B”).  The star's radius is taken to be 0.12 solar radii and distance is taken to be 12.1 pc.  GJ 832 is an M1.5V star that hosts two planets: a 0.64 M_J planet at a semimajor axis of 3.56 au and a 5.4 M_E super-Earth located in the canonical habitable zone (0.16 au).  The star's radis is taken to be 0.50 solar radii and distance is taken to be 0.96 pc.  GJ 176 is an M 2.5V star that hosts an 8.3 M_E planet orbiting at 0.66 au.  The star's radius is taken to be 0.45 solar radii and distance is taken to be 9.47 pc.  GJ 436 is an M3.5 V star that hosts a 23 M_E planet orbiting at 0.287 au. Lyα transit observations of this Neptune-sized planet show a 56% transit depth that is most likely caused by a large cloud of escaping hydrogen (Kulow et al. 2014; Ehrenreich et al. 2015).  The star's radius is taken to be 0.46 solar radii and distance is taken to be 9.76 pc.

Acknowledgements

If you make use of the synthetic HAZMAT spectral data products, please cite Peacock et al. (2020).  If you make use of the synthetic TRAPPIST-1 spectral data products, please cite Peacock et al. (2019a).  If you make use of the synthetic GJ 832, GJ 176, or GJ 436 spectral data products, please cite Peacock et al. (2019b).

Data Products

Data file naming convention (except for TRAPPIST and GJ stars):

hlsp_hazmat_phoenix_synthspec_<age>myr_<emtype>-m<mass>-t<temp>-g<grav>_v1_fullres.<ext> 

where:

  • <age> = Age of the model, in Myr, as a four-digit, zero-padded string.
  • <emtype> = EUV-NUV emission level, one of "lq", "max", "med", "min", or "uq".
    • "lq" = Lower Quartile levels of emission.
    • "max" = Maximum levels of emission.
    • "med" = Median levels of emission.
    • "min" = Minimum levels of emission. NOTE: There are no "min" models for the 5000 Myr models.
    • "uq" = Upper Quartile levels of emission.
  • <mass> = Mass of star, either "0.35" or "0.45", in solar masses.
  • <temp> = Effective temperature of star, as a four-digit string, in Kelvin.
  • <grav> = Surface gravity of the star, out to two decimal places (e.g., "4.60").
  • <ext> = "fits" or "txt" version of the model.

For TRAPPIST and GJ star models:

hlsp_hazmat_phoenix_synthspec_<star>_<model>_v1_fullres.<ext> 

where:

  • <star> = Name of the star.
  • <model> = Model group (for TRAPPIST-1), either "1a", "2a", or "2b", or "model" for GJ stars.
  • <ext> = "fits" or "txt" version of the model.

Data file types:

_fullres.fits FITS version of the model.
_fullres.txt TEXT version of the model.

Data Access

Sample Scripts

To get started, here are some Python and IDL lines to read in the model spectra, provided by the HLSP team.  MAST provides these for convenience, but does not take responsibility for long-term maintenance of these commands.

Python
from astropy.io import fits
import matplotlib.pyplot as plt
spec = fits.getdata(‘hlsp_hazmat_phoenix_synthspec_10myr_med-m0.45-t3550-g4.24_v1_fullres.fits’,1)
plt.plot(spec['WAVELENGTH'],spec['FLUX'])
plt.suptitle('10 Myr, M=0.45 Msun Median Model’)
plt.xlabel('Wavelength (Angstroms)')
plt.ylabel('Flux Density (erg/cm2/s/Ang)')
plt.show()

from astropy.io import ascii
import matplotlib.pyplot as plt
spec = ascii.read(“hlsp_hazmat_phoenix_synthspec_10myr_med-m0.45-t3550-g4.24_v1_fullres.txt”)
plt.plot(spec[0],spec[1])
plt.suptitle('10 Myr, M=0.45 Msun Median Model’)
plt.xlabel('Wavelength (Angstroms)')
plt.ylabel('Flux Density (erg/cm2/s/Ang)')
plt.show()
IDL
spec = MRDFITS(‘hlsp_hazmat_phoenix_synthspec_10myr_med-m0.45-t3550-g4.24_v1_fullres.fits’,1,head)
plot,spec.wavelength,spec.flux,xrange=[100,3000],/xlog,/ylog,$
       charsize=2,charthick=2,title=’10 Myr, M=0.45 Msun Median Model’,$
       xtitle='Wavelength (Angstroms)’, ytitle='Flux Density (erg/cm2/s/Ang)',$
       
readcol,‘hlsp_hazmat_phoenix_synthspec_10myr_med-m0.45-t3550-g4.24_v1_fullres.txt’,wavelength, flux
plot,wavelength,flux,xrange=[100,3000],/xlog,/ylog,$
       charsize=2,charthick=2, title=’10 Myr, M=0.45 Msun Median Model’,$
       xtitle='Wavelength (Angstroms)’, ytitle='Flux Density (erg/cm2/s/Ang)',$

Data Tables

10 Myr Synthetic Spectra
Mass Minimum Lower Quartile Median Upper Quartile Maximum
0.35 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT
0.45 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT

 

45 Myr Synthetic Spectra
Mass Minimum Lower Quartile Median Upper Quartile Maximum
0.35 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT
0.45 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT

 

120 Myr Synthetic Spectra
Mass Minimum Lower Quartile Median Upper Quartile Maximum
0.35 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT
0.45 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT

 

650 Myr Synthetic Spectra
Mass Minimum Lower Quartile Median Upper Quartile Maximum
0.35 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT
0.45 FITS | TXT FITS | TXT FITS | TXT FITS | TXT FITS | TXT

 

5 Gyr Synthetic Spectra
Mass Minimum Lower Quartile Median Upper Quartile Maximum
0.35 None FITS | TXT FITS | TXT FITS | TXT FITS | TXT
0.45 None FITS | TXT FITS | TXT FITS | TXT FITS | TXT

 

Other Synthetic Spectra - TRAPPIST-1
Star Model Group 1a Model Group 2a Model Group 2b
TRAPPIST-1 FITS | TXT FITS | TXT FITS | TXT

 

Other Synthetic Spectra - GJ Stars
Star Models
GJ 176 FITS | TXT
GJ 436 FITS | TXT
GJ 832 FITS | TXT

Citations

Please remember to cite the appropriate paper(s) below and the DOI if you use these data in a published work. 

Note: These HLSP data products are licensed for use under CC BY 4.0.

References