Nineteen new Wolf-Rayet stars discovered in the Andromeda galaxy

Utilizing the 4.3-m Lowell Discovery Telescope (LDT), astronomers Kathryn F. Neugent and Philip Massey, have noticed the close by Andromeda galaxy. In consequence, they detected 19 new Wolf-Rayet stars on this galaxy. The discovering was reported in a paper printed June 22 on the pre-print server arXiv.

Wolf-Rayet (WR) stars are extraordinarily scorching and really luminous stars with robust, broad helium emission strains. Observations present that WRs are large stars at a complicated stage of stellar evolution and shedding mass at a really excessive fee. To this point, just a few a whole lot such stars have been found, largely within the Milky Way.

Now, Kathryn F. Neugent from the Harvard-Smithsonian Middle for Astrophysics (CfA) and Philip Massey from the Lowell Observatory, report the detection of one other batch of WR stars. They detected 19 new objects of this kind within the neighboring Andromeda galaxy (often known as Messier 31, or M31) utilizing LDST’s Massive Monolithic Imager (LMI).

“Our improved imaging knowledge and spectroscopic follow-up confirmed 19 new WRs throughout three small fields in M31,” the researchers wrote within the paper.

The scientists investigated 30 WR candidates with LMI in late 2021 and spectroscopically confirmed 19 of them utilizing the 6.5-m MMT telescope within the second half of 2022, Most of them turned out to be of the WN sort (nitrogen-rich). The newfound WRs are usually fainter than the beforehand recognized pattern of such stars within the Andromeda galaxy, attributable to barely elevated reddening.

It was famous that the overwhelming majority of the newly detected WR stars weren’t discovered within the earlier galaxy-wide survey as a result of lack of observational sensitivity. The astronomers added that the median magnitude (within the WN filter of the LMI) is 21.0, in comparison with the median WN magnitude of the 150 beforehand recognized WRs, which is nineteen.2.

The authors of the paper estimate that about 60 extra Wolf-Rayet stars are left to be discovered within the Andromeda galaxy. Provided that WRs aren’t evenly distributed throughout this galaxy, however they’re usually confined to their birthplaces, the researchers plan to concentrate on these particular areas as a way to determine extra stars of this kind.

Summing up the outcomes, the astronomers famous that the general ratio of WN-type to WC-type (carbon-rich) WRs for Andromeda stays unchanged with their latest findings. They plan to proceed the present survey, with the purpose of finishing the census of WR stars inhabitants on this galaxy.

“We stay up for persevering with this survey within the upcoming observing seasons…. Our up to date pattern will higher constrain the RSG/WR [red supergiant/Wolf-Rayet] ratio mentioned in Massey et al. (2021a), enable for extra correct comparisons with evolutionary fashions, and finally assist us higher perceive the evolution and finish states of massive stars,” the researchers concluded.

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