Journal article
Chandra/HETG and NuSTAR Observations of V750 Ara, a γ Cas-type Star
The Astrophysical journal, Vol.993(2), 220
11/10/2025
DOI: 10.3847/1538-4357/ae10b5
Abstract
We present a 197 ks HETG and 95 ks NuSTAR spectra of the γ Cas-type object V750 Ara. The high-resolution X-ray spectra show that the target is similar to other objects of this class. Data are interpreted under the assumption that the X-rays come from an accreting white dwarf, and our analysis implies an accretion rate of about 3 × 10−11 M⊙ yr−1. Emission lines are weak and predominantly from hydrogen-like ions: Mg XII, Si XIV, and S XVI. H-like and He-like Fe are both present, but Fe K fluorescence is weak, being significantly detected only in the NuSTAR spectrum, but it was not obviously detected in the HETG dispersed or zeroth-order spectra. The flux was variable above a level expected by Poisson statistics. There were no significant changes in the spectral hardness, though we are limited by lack of soft signal below 1 keV. Emission lines of Mg and Si were strong enough to measure velocity offsets and widths that were found to be marginally inconsistent. The H-like Mg line is consistent with instrumental broadening only but shows a 300 km s−1 blueshift. He-like Mg and H-like Si lines have no significant shift in velocity but are broadened by about 1000 km s−1. This suggests either different physical origins or velocity structure differing with plasma temperature.
Details
- Title: Subtitle
- Chandra/HETG and NuSTAR Observations of V750 Ara, a γ Cas-type Star
- Creators
- David P HuenemoerderSean J GundersonRichard IgnaceJoy S NicholsA. M. T PollockPragati PradhanNorbert S SchulzDustin K SwarmJosé M Torrejón
- Resource Type
- Journal article
- Publication Details
- The Astrophysical journal, Vol.993(2), 220
- DOI
- 10.3847/1538-4357/ae10b5
- ISSN
- 0004-637X
- eISSN
- 1538-4357
- Publisher
- IOP Publishing
- Grant note
- SI divided by Smithsonian Astrophysical Observatory (SAO): GO3-24004A
Support for S.J.G. and D.P.H. was provided the Smithsonian Astrophysical Observatory (SAO) Chandra X-Ray Center (CXC) Award GO3-24004A and by NASA through the SAO contract SV3-73016 to MIT for Support of the CXC and Science Instruments. CXC is operated by SAO for and on behalf of NASA under contract NAS8-03060. S.J.G. and HMG also received support by NASA through Chandra Award Number GO3-24005X issued by the CXC. J.M.T. acknowledges the grant ASFAE/2020/02 from Generalitat Valenciana.
- Language
- English
- Date published
- 11/10/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9985024137202771
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