Astronomers have discovered a new short-period brown dwarf

Complete NGTS light curve for NGTS-28AB with transit positions marked by red dashed lines. Credit: Henderson et al., 2024

An international team of astronomers has discovered a new brown dwarf by analyzing data from the Next Generation Transit Survey (NGTS). The newly found object, designated NGTS-28Ab, orbits its host star in about 30 hours. This discovery was reported in a paper. Posted February 15 on the preprint server arXiv.

Brown dwarfs (BDs) are objects intermediate between planets and stars, occupying a mass range between 13 and 80 Jupiter masses (0.012 and 0.076 solar masses). Although many Discovered to date, these objects orbiting other stars are a rare find.

Now, a team of astronomers led by Beth A. Henderson of the University of Leicester in the UK has reported the discovery of such a rare new BD. Using data from NGTS and NASA’s Transiting Exoplanet Survey Satellite (TESS), they conducted the research. Known as NGTS-28.

“We first identified a brown dwarf within the Next Generation Transit Survey data, with supporting observations in TESS Sectors 11 and 38,” the researchers wrote in the paper.

The team identified a large object orbiting the primary star in the system—an M dwarf known as NGTS-28A. The brown dwarf nature of this object was confirmed by follow-up observations using several ground-based facilities, including the South African Astronomical Observatory (SAAO).

The newly discovered brown dwarf is slightly smaller than Jupiter (0.95 Jupiter radii), but 69 times more massive than the largest planet in the Solar System. This produces a surface density of about 98.7 g/cm.3.

According to the paper, NGTS-28Ab orbits its parent star every 30.1 hours, at a distance of some 0.02 AU. A brown dwarf has an equilibrium temperature of about 863 K and is estimated to be at least 500 million years old.

When it comes to NGTS-28A, it is about half the size and mass of the Sun. It has one. 3,626 K and is about 7 billion years old. The companion NGTS-28B has a similar effective temperature, but is about a third smaller and less massive than the parent star. This system is located about 404 light years away.

The results make NGTS-28Ab one of the shortest transiting BDs within the “brown dwarf desert” – the dearth of objects that orbit very close to main-sequence stars (within 3 AU). NGTS-28Ab is orbiting one of the hottest M dwarfs in this desert.

“NGTS-28Ab provides a new opportunity to gain a deeper understanding of this region. The brown dwarf desert is thought to be due to the minimal overlap of the distribution tails between planets and star formation mechanisms. . which could indicate the composition of everything,” the study’s authors concluded.

More information:
Beth A. Henderson et al, NGTS-28Ab: A Short Period of Brown Dwarf Transition, arXiv (2024). DOI: 10.48550/arxiv.2402.09943

Journal Information:

© 2024 ScienceX Network

Reference: Astronomers Discover a New Short-Period Brown Dwarf (2024, February 23) Retrieved February 23, 2024 from https://phys.org/news/2024-02-astronomers-short-period-brown-dwarf.html Obtained

This document is subject to copyright. No part may be reproduced without written permission, except for any fair dealing for the purpose of private study or research. The content is provided for informational purposes only.