Chandra X-ray analysis of Herbig Ae/Be stars

Title

Chandra X-ray analysis of Herbig Ae/Be stars

Creator

Anilkumar H.; Mathew B.; Jithesh V.; Kartha S.S.; Manoj P.; Narang M.; Chavali M.

Description

Herbig Ae/Be (HAeBe) stars are intermediate-mass pre-main-sequence stars, characterized by infrared (IR) excess and emission lines. They are observed to emit X-rays, whose origin is a matter of discussion and not settled yet. X-ray emission is not expected in HAeBe stars, as they lack the subsurface convective zone. In this study, we retrieved observations from the Chandra archive for 62 HAeBe stars, among which 44 sources (detection fraction ?71 per cent) were detected in X-rays, with 7 being new detections. We use this sample as a test bed to conduct a comparative analysis of the X-ray properties of HAeBe stars and their low-mass counterparts, T Tauri stars (TTSs). Further, we compare the X-ray properties of HAeBe stars and TTSs with optical and IR properties to constrain the X-ray emission mechanism in HAeBe stars. We found no correlation between X-ray emission and disc properties of HAeBe stars, confirming that X-rays are not related to accretion shocks. About 56 per cent of HAeBe stars without any known subarcsec companions have lower plasma temperatures (kT ? 2 keV). We observe flaring/variability in HAeBe stars with confirmed low-mass companions. These stars show plasma temperatures > 2 keV, similar to TTSs. Guided by this information, we discuss the role of a T Tauri companion for X-ray emission seen in our sample of HAeBe stars. From the results obtained in this paper, we suggest that X-ray emission from HAeBe stars may not be related to accretion shocks or hidden TTS, but rather can be due to magnetically driven coronal emission. 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Source

Monthly Notices of the Royal Astronomical Society, Vol-530, No. 3, pp. 3020-3037.

Date

2024-01-01

Publisher

Oxford University Press

Subject

stars: coronae; stars: flare; stars: low-mass; stars: massive; stars: pre-main-sequence; techniques: imaging spectroscopy

Coverage

Anilkumar H., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, 560029, India; Mathew B., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, 560029, India; Jithesh V., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, 560029, India; Kartha S.S., Department of Physics and Electronics, CHRIST (Deemed to be University), Bangalore, 560029, India; Manoj P., Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005, India; Narang M., Academia Sinica Institute of Astronomy and Astrophysics, 11F of Astro-Math Bldg., No. 1, Section 4, Roosevelt Road Republic of China, Taipei, 10617, Taiwan; Chavali M., Max Planck Institute for Radio Astronomy, Auf dem Hel 69, Bonn, D-53121, Germany

Rights

All Open Access; Gold Open Access

Relation

ISSN: 358711; CODEN: MNRAA

Format

Online

Language

English

Type

Article

Identifier

https://doi.org/10.1093/mnras/stae938

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