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HO Telescopii
	; A visual band light curve for HO Telescopii, adapted from Sürgit et al. (2017)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Telescopium
Right ascension	19h 51m 58.93159s
Declination	−46° 51′ 42.4354″
Apparent magnitude (V)	8.22 (Max)
Characteristics
Spectral type	A7III(m)
Variable type	Algol
Astrometry
Radial velocity (Rv)	−5.91±0.09 km/s
Proper motion (μ)	RA: +1.814 mas/yr ; Dec.: −33.369 mas/yr
Parallax (π)	3.5831 ± 0.0796 mas
Distance	910 ± 20 ly ; (279 ± 6 pc)
Orbit
Period (P)	1.613097 d
Semi-major axis (a)	≥0.019±0.0001 AU
Eccentricity (e)	0.00
Inclination (i)	82.7±0.5°
Periastron epoch (T)	2,451,875.06581±0.00027 HJD
Semi-amplitude (K1); (primary)	131.11±0.18 km/s
Semi-amplitude (K2); (secondary)	142.35±0.18 km/s
Details
A
Mass	1.88±0.04 M☉
Radius	2.28±0.15 R☉
Age	1.1 Gyr
B
Mass	1.73±0.04 M☉
Radius	2.08±0.16 R☉
Other designations
	HO Tel, CD−47°13121, HD 187418, HIP 97756, SAO 229902
Database references
SIMBAD	data

HO Telescopii is an eclipsing binary star system located in the southern constellation of Telescopium. The maximum apparent visual magnitude of 8.22^[3] is too faint to be visible to the naked eye. The system is located at a distance of approximately 910 light years based on parallax.^[2] The combined stellar classification of the system is A7III(m),^[4] matching an evolved A-type star^[10] that is possibly metallic-lined. The system is around 1.1^[1] billion years old and consists of two stars of similar mass and size.^[1]

The variability of this system was discovered by W. Strohmeier, R. Knigge, and H. Ott in 1965.^[11]^[12] It is a detached binary system with both components filling three-fourths of their respective Roche lobes.^[1] Their orbital period is 1.613097^[6] days with a circularized orbit,^[7] and the orbital plane is inclined by 83° to the line of sight from the Earth; close to edge-on.^[8] As a consequence, they form an Algol-like eclipsing binary with a magnitude decrease of 0.51 during the primary eclipse and 0.45 during the secondary eclipse.^[3]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Sürgit, D.; et al. (July 2017). "Absolute parameters of detached binaries in the southern sky - III: HO Tel". New Astronomy. 54: 109–114. Bibcode:2017NewA...54..109S. doi:10.1016/j.newast.2017.01.013.
^ ^a ^b ^c ^d ^e ^f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ ^a ^b ^c Avvakumova, E. A.; et al. (October 2013). "Eclipsing variables: Catalogue and classification". Astronomische Nachrichten. 334 (8): 860. Bibcode:2013AN....334..860A. doi:10.1002/asna.201311942. hdl:10995/27061.
^ ^a ^b Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 2. Ann Arbor: Dept. of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
^ ^a ^b ^c Sürgit, D.; et al. (July 2015). Rucinski, Slavek M.; Torres, Guillermo; Zejda, Miloslav (eds.). "First Spectroscopic Solutions of Two Southern Eclipsing Binaries: HO Tel and QY Tel". Living Together: Planets, Host Stars and Binaries, Proceedings of a conference held 8-12 September 2014 in Litomyšl, Czech Republic. ASP Conference Series. 496. San Francisco: Astronomical Society of the Pacific: 258. Bibcode:2015ASPC..496..258S.
^ ^a ^b Khaliullin, Kh. F.; Khaliullina, A. I. (January 2010). "Synchronization and circularization in early-type binaries on main sequence". Monthly Notices of the Royal Astronomical Society. 401 (1): 257–274. Bibcode:2010MNRAS.401..257K. doi:10.1111/j.1365-2966.2009.15630.x.
^ ^a ^b Grygar, J.; Horak, T. B. (1980). "Orbital Elements of the Eclipsing Binaries RW CrA and HO Tel from Multicolour Light Curves". Bulletin of the Astronomical Institute of Czechoslovakia. 31: 297. Bibcode:1980BAICz..31..297G.
^ "HO Tel". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-12.
^ Spoelstra, T. A. Th.; Van Houten, C. J. (1972). "Five-colour photometry of the eclipsing binary HO Telescopii". Astronomy and Astrophysics Supplement. 7: 83. Bibcode:1972A&AS....7...83S.
^ Sistero, R. F.; Candellero, B. A. (August 1979). "HO Telescopii: Light Elements". Information Bulletin on Variable Stars. 1666: 1. Bibcode:1979IBVS.1666....1S.
^ Strohmeier, W.; et al. (February 1965). "Bright Southern BV-Stars". Information Bulletin on Variable Stars. 81: 1. Bibcode:1965IBVS...81....1S.