Positioned proximate to the youthful open star cluster IC 348 near the eastern periphery of the Perseus dark cloud complex, HH 797 commands the lower portion of this visual composition. In the upper segment of the image, bright infrared entities are believed to harbor two additional protostars.
Taken using Webb’s Near-InfraRed Camera (NIRCam), this image highlights the potency of infrared imaging for investigating nascent stars and their emanations. Given that the youngest stars typically remain ensconced within the gas and dust of their formation, the infrared radiation from the star’s outflows effectively pierces through the obstructing layers of gas and dust. This unique attribute makes Herbig-Haro objects particularly well-suited for scrutiny using the sensitive infrared instruments on board the Webb telescope.
In the midst of turbulent conditions, molecules such as molecular hydrogen and carbon monoxide become energized, emitting infrared light that the Webb telescope captures to depict the configuration of the outflows. NIRCam excels in observing the heated molecules, reaching temperatures in the thousands of degrees Celsius, which become stimulated due to the occurrence of shocks.
Through observations conducted from ground-based instruments, scientists had previously determined that concerning the cold molecular gas linked to HH 797, the majority of the gas exhibiting a red shift (moving away from our vantage point) is situated in the southern region (bottom right), whereas the blue-shifted gas (moving towards us) is concentrated in the northern area (bottom left). Additionally, a gradient was identified traversing the outflow. This gradient indicates that, at a specific distance from the youthful central star, the gas velocity on the eastern periphery of the jet tends to be more red-shifted compared to the gas along the western edge.
Historically, astronomers attributed the observed velocity discrepancies in the outflow to its rotational dynamics. However, the enhanced resolution provided by the Webb telescope challenges this interpretation. Instead, the higher-resolution image reveals that what was initially perceived as a single outflow is, in reality, composed of two nearly parallel outflows, each generating its own distinct series of shocks, thereby elucidating the observed velocity asymmetries. The source, located in a small dark region near the bottom right of the center, previously identified through prior observations, is not a solitary star but a binary system. Each star within this system is responsible for generating its own striking outflow. The image also showcases additional outflows, including one originating from the protostar in the upper right of the center, accompanied by its illuminated cavity walls.
Situated just north of HH 211 with an approximate separation of 30 arcseconds, HH 797 shares celestial proximity with the feature highlighted in a Webb image release from September 2023.
Resources
- ONLINE NEWS European Space Agency. (2023, November 29). Webb captures a prominent protostar in Perseus. Phys.org. [Phys.org]
- JOURNAL Ray, T. P., McCaughrean, M. J., O Garatti, A. C., Kavanagh, P., Justtanont, K., Van Dishoeck, E., Reitsma, M. L., Beuther, H., Francis, L., Gieser, C., Klaassen, P., Perotti, G., Tychoniec, Ł., Van Gelder, M., Colina, L., Greve, T. R., Güdel, M., Henning, T., Lagage, P. O., . . . Wright, G. (2023). Outflows from the youngest stars are mostly molecular. Nature, 622(7981), 48–52. [Nature]
Cite this page:
APA 7: TWs Editor. (2023, November 29). A Protostar in Perseus Shines Brightly in Webb’s View. PerEXP Teamworks. [News Link]
