THA 15-31 : Discovery with VLT/X-shooter and Swift /UVOT of a new symbiotic star of the accreting-only variety
(2022) In Astronomy and Astrophysics 661.- Abstract
We report the discovery and characterization of a new symbiotic star of the accreting-only variety, which we observed in the optical/near-infrared (NIR) with VLT/X-shooter and in the X-rays/ultraviolet with Swift/UVOT+XRT. The new symbiotic star, THA 15-31, was previously described as a pre-main sequence star belonging to the Lupus 3 association. Our observations, ancillary data, and Gaia EDR3 parallax indicate that THA 15-31 is a symbiotic star composed of an M6III red giant and an accreting companion, is subject to EB 0.38 reddening, and is located at a distance of 12 kpc and at 1.8 kpc above the Galactic plane in the outskirts of the Bulge. The luminosity of the accreting companion is 100, placing THA 15-31 among the symbiotic stars... (More)
We report the discovery and characterization of a new symbiotic star of the accreting-only variety, which we observed in the optical/near-infrared (NIR) with VLT/X-shooter and in the X-rays/ultraviolet with Swift/UVOT+XRT. The new symbiotic star, THA 15-31, was previously described as a pre-main sequence star belonging to the Lupus 3 association. Our observations, ancillary data, and Gaia EDR3 parallax indicate that THA 15-31 is a symbiotic star composed of an M6III red giant and an accreting companion, is subject to EB 0.38 reddening, and is located at a distance of 12 kpc and at 1.8 kpc above the Galactic plane in the outskirts of the Bulge. The luminosity of the accreting companion is 100, placing THA 15-31 among the symbiotic stars accreting at a high rate (2.5 10-8 yr-1 if the accretion is occurring on a white dwarf of 1M). The observed emission lines originate primarily from H I, He I, and Fe II, with no He II or other high-excitation lines observed; a sharp central absorption superimposed on the Balmer emission lines is observed, while all other lines have a simple Gaussian-like profile. The emission from the companion dominates over the M6III red giant at U and B-band wavelengths, and is consistent with an origin primarily in an optically thick accretion disk. No significant photometric variability is observed at optical or NIR wavelengths, suggesting either a face-on orbital orientation and/or that the red giant is far from Roche-lobe filling conditions. The profile of emission lines supports a low orbital inclination if they form primarily in the accretion disk. An excess emission is present in AllWISE W3 (12 μm) and W4 (22 μm) data, radiating a luminosity, consistent with thermal emission from optically thin circumstellar dust.
(Less)
- author
- Munari, U. ; Alcalá, J. M. ; Frasca, A. ; Masetti, N. ; Traven, G. LU ; Akras, S. and Zampieri, L.
- organization
- publishing date
- 2022-05-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Binaries: symbiotic
- in
- Astronomy and Astrophysics
- volume
- 661
- article number
- A124
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85131231794
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/202142058
- language
- English
- LU publication?
- yes
- id
- 0c0aafb5-a200-4a44-8169-afc22403015e
- date added to LUP
- 2022-10-28 11:20:59
- date last changed
- 2024-04-18 15:19:05
@article{0c0aafb5-a200-4a44-8169-afc22403015e,
abstract = {{<p>We report the discovery and characterization of a new symbiotic star of the accreting-only variety, which we observed in the optical/near-infrared (NIR) with VLT/X-shooter and in the X-rays/ultraviolet with Swift/UVOT+XRT. The new symbiotic star, THA 15-31, was previously described as a pre-main sequence star belonging to the Lupus 3 association. Our observations, ancillary data, and Gaia EDR3 parallax indicate that THA 15-31 is a symbiotic star composed of an M6III red giant and an accreting companion, is subject to EB 0.38 reddening, and is located at a distance of 12 kpc and at 1.8 kpc above the Galactic plane in the outskirts of the Bulge. The luminosity of the accreting companion is 100, placing THA 15-31 among the symbiotic stars accreting at a high rate (2.5 10-8 yr-1 if the accretion is occurring on a white dwarf of 1M). The observed emission lines originate primarily from H I, He I, and Fe II, with no He II or other high-excitation lines observed; a sharp central absorption superimposed on the Balmer emission lines is observed, while all other lines have a simple Gaussian-like profile. The emission from the companion dominates over the M6III red giant at U and B-band wavelengths, and is consistent with an origin primarily in an optically thick accretion disk. No significant photometric variability is observed at optical or NIR wavelengths, suggesting either a face-on orbital orientation and/or that the red giant is far from Roche-lobe filling conditions. The profile of emission lines supports a low orbital inclination if they form primarily in the accretion disk. An excess emission is present in AllWISE W3 (12 μm) and W4 (22 μm) data, radiating a luminosity, consistent with thermal emission from optically thin circumstellar dust.</p>}},
author = {{Munari, U. and Alcalá, J. M. and Frasca, A. and Masetti, N. and Traven, G. and Akras, S. and Zampieri, L.}},
issn = {{0004-6361}},
keywords = {{Binaries: symbiotic}},
language = {{eng}},
month = {{05}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{THA 15-31 : Discovery with VLT/X-shooter and Swift /UVOT of a new symbiotic star of the accreting-only variety}},
url = {{http://dx.doi.org/10.1051/0004-6361/202142058}},
doi = {{10.1051/0004-6361/202142058}},
volume = {{661}},
year = {{2022}},
}