A closer look at the young stellar group around Sh 2-295

Abstract

Star formation is governed by multiple physical processes, making it inherently complicated. One excellent example is the Canis Major OB1/R1 Association, whose complex history of star formation is related to different episodes. Three supernova (SN) events potentially altered the environment and impacted star formation and stellar evolution. Prior investigations revealed two stellar groups of different ages associated with GU CMa and Z CMa. This work focusses on identifying the low-mass young stellar population near FZ CMa, located between these two groups and spatially related to the H II region Sh 2-295. Our main goal is to verify whether this group is age-mixed and characterise its physical properties. We analysed multi-object spectroscopic data acquired with Gemini/GMOS to search for typical features of T Tauri stars (TTs) and to determine their spectral types. Lithium absorption line ($\lambda$ 6708 $\mathring{A}$) was used as a youth indicator, while H$\alpha$ emission was investigated to probe accretion activity. We also derived ages based on optical photometry from Gaia DR3 and compared the projected spatial distribution to diffuse infrared (IR) emission. We identified 29 TTs, including six new members of the association and three Classical TTs (CTTs). The equivalent width of the Li I absorption line suggests an age of $8.1_{-3.8}^{+2.1}$ Myr, while optical photometric data indicate stellar ages ranging from $\sim$1 to 14 Myr. Younger stars are concentrated around Sh 2-295, whereas the older ones are more widely dispersed. We increased the number of known TTs related to the CMa association. Our results support a scenario of multiple star-formation episodes, including a younger group that may have been triggered by the expansion of Sh 2-295. The influence of SN events appears limited in this context.

9 pages, 3 tables, 7 figures, and 4 pages of supplementary material to be published in A&A

References in corpus (20)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• Gaia Data Release 3: Summary of the content and survey properties
• Improving PARSEC models for very low mass stars
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties
• The Zwicky Transient Facility Catalog of Periodic Variable Stars
• Constraining the thermally-pulsing asymptotic giant branch phase with resolved stellar populations in the Small Magellanic Cloud
• Gaia Data Release 3: Analysis of the Gaia BP/RP spectra using the General Stellar Parameterizer from Photometry
• One Relation for All Wavelengths: The Far-Ultraviolet to Mid-Infrared Milky Way Spectroscopic R(V) Dependent Dust Extinction Relationship
• Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud
• The Gaia-ESO Survey: Empirical estimates of stellar ages from lithium equivalent widths (EAGLES)
• A Blind All-sky Search for Star Clusters in Gaia EDR3: 886 Clusters within 1.2 kpc of the Sun
• The Keele-Exeter young cluster survey: I. Low mass pre-main sequence stars in NGC 2169
• The radial metallicity gradient and the history of elemental enrichment in M81 through emission-line probes
• Spectral library of age-benchmark low-mass stars and brown dwarfs
• Canis Major OB1 stellar groups contents revealed by Gaia
• Spectroscopic characterization of X-ray emitting young stars associated with the Sh 2-296 nebula
• Star formation and accretion rates within 500 pc as traced by Gaia DR3 XP spectra
• Searching for active low-mass stars in CMa star-forming region: multi-band photometry with T80S