Mission Overview
Light Curves of Young Stars from TESS (TESS-YSO)
Primary Investigator: Ann Marie Cody
HLSP Authors: Ann Marie Cody, Shreya Chandragiri
Released: 2025-11-11
Updated: 2025-11-11
Primary Reference(s): Cody et al. 2025
DOI: 10.17909/fkzx-2z29
Citations: See ADS Statistics
Source Data:
- MAST Portal DOI
- TESS GI Proposals G011285, G022236
Overview
Throughout its mission, the Transiting Exoplanet Survey Satellite (TESS) has observed thousands of young stellar objects (YSOs) at ages of less than ~10 million years (Myr). Observed at sampling rates of 30 minutes or less, these targets are scattered across the sky and associated with various star forming regions. The team has created and analyzed custom light curves from TESS Full Frame Images, with a focus on preserving the variability associated with YSOs. The photometric pipeline consists of a mixture of circular aperture photometry and custom pixel masks, from which the best light curve was chosen for each target. Care was taken to maximize photometric precision and minimize systematic effects, while avoiding blends with stellar neighbors.
The resulting light curves are provided here as a function of stellar type, circumstellar disk status, and host cluster (if known), as determined in the listed reference papers. In the first release, the HLSP team provides light curves for young intermediate mass stars with spectral types G through O. The team refers to these as "Herbig Ae/Be stars" since the majority are A and B type with emission lines due to accretion from a circumstellar disk. While alternate light curve versions exist for some of the targets, the reduction procedures for these products have been tuned to retain all sources of astrophysical variability.
Data Products
TESS-YSO includes light curve files designed to be similar in format to those provided by the TESS mission. For more details about the contents and column names in each file, please see the README.
Data file naming convention:
hlsp_tess-yso_tess_ffi_s<sector>-tic<ticid>_tess_v1.0_lc.fits
where:
- <sector> is the Sector number, zero-padded to 4 digits (e.g., Sector 19 is 0019), and
- <ticid> is the TESS Input Catalog identifier, zero-padded to 16 digits (e.g., 261539498 becomes 0000000261539498).
Data file types:
| _lc.fits | Light curve file |
Data Access
MAST Portal and Astroquery
The TESS-YSO data products are available in the MAST Search Portal (web-based, cross-mission search interface) and Astroquery (Python package to search for and download files from Python scripts you write).
- A direct portal link to the TESS-YSO data is provided here.
- Alternatively, in the MAST Search Portal, set the Provenance Name filter to "TESS-YSO" in an Advanced Search to find these data. The user guide for how to search and download products using the MAST Portal is available here.
- For Astroquery, the following example code demonstrates how to search for and download these products. This code assumes that you want to download all products from this HLSP, so you may want to consider narrowing down your search for large HLSPs (> 10 GB) or those with many individual files (> 10k). You can find more astroquery.mast tutorials here.
from astroquery.mast import Observations
# Search for all TESS-YSO products
all_obs = Observations.query_criteria(provenance_name="TESS-YSO")
data_products = Observations.get_product_list(all_obs)
# Print the number of data products that would be downloaded
print(len(data_products))
# Download data
Observations.download_products(data_products)
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A web-based interface for cross-mission searches of data at MAST or the Virtual Observatory.
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Search for and download data products for this HLSP programmatically in Python.
Code Examples
The authors of this HLSP have provided a code example for working with the data in Python, shown below.
Open and plot a TESS-YSO light curve using lightkurve
Here's a quick example showing how to open and plot a light curve using the lightkurve package. The files contain all the necessary metadata to be read by lightkurve.TessLightCurve.read or lightkurve.io.generic.read_generic_lightcurve, but the default lightkurve.read method will not work at this time.
import matplotlib.pyplot as plt
import lightkurve as lk
# Open File
filename = "hlsp_tess-yso_tess_ffi_s0005-tic0000000213103713_tess_v1.0_lc.fits"
mylc = lk.TessLightCurve.read(filename)
# Plot the light curve
mylc.scatter()
plt.show()