Theta Indi

θ Indi
	Location of θ Indi (circled)
Observation data; Epoch J2000 Equinox ICRS
Constellation	Indus
Right ascension	21h 19m 51.9895s
Declination	−53° 26′ 57.934″
Apparent magnitude (V)	+4.39
Characteristics
Spectral type	A5IV-V
B−V color index	+0.191±0.004
Astrometry
Radial velocity (Rv)	−14.50 km/s
Proper motion (μ)	RA: +106.99 mas/yr ; Dec.: −66.46 mas/yr
Parallax (π)	33.0546±0.0948 mas
Distance	98.7 ± 0.3 ly ; (30.25 ± 0.09 pc)
Absolute magnitude (MV)	+1.98
Details
A
Mass	1.774±0.040 M☉
Radius	1.736±0.062 R☉
Luminosity	11.9±0.7 L☉
Surface gravity (log g)	4.208±0.032 cgs
Temperature	8,133±70 K
Metallicity [Fe/H]	+0.08 dex
Rotational velocity (v sin i)	135 km/s
Age	617±179 Myr
Ba
Mass	1.08 M☉
Bb
Mass	0.53 M☉
Other designations
	CPD−53°10037, GC 29819, HIP 105319, HR 8140, HD 202730, SAO 246965, WDS J21199-5327AB
Database references
SIMBAD	data

Theta Indi (θ Ind) is a binary star in the constellation Indus. Its apparent magnitude is +4.39 and it is approximately 98.7 light years away based on parallax.

The smaller companion, B, has a spectral type of G0V (yellow main-sequence) and an apparent magnitude of 7.18 at a separation of 6.71″. It is a binary system itself with an orbital period of 30 years. Its components have masses of 1.08 and 0.54 M_☉.

Interferometric observations suggest the primary is itself a binary with components Aa and Ab orbiting at 0.0617″, estimated period about 1.3 years, although the star does not exhibit the radial velocity variations and astrometric anomalies expected for such a companion.

References

1 2 3 4 5 6 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry
1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
↑ Gray, R. O.; Garrison, R. F. (July 1989), "The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation", Astrophysical Journal Supplement Series, 70 (4): 623–636, Bibcode:1989ApJS...70..623G, doi:10.1086/191349
↑ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W, LCCN 54001336
1 2 3 4 5 6 Tuchow, Noah W.; Stark, Christopher C.; Mamajek, Eric (2024-02-29). "HPIC: The Habitable Worlds Observatory Preliminary Input Catalog". The Astronomical Journal. 167 (3): 139. arXiv:2402.08038. doi:10.3847/1538-3881/ad25ec. ISSN 0004-6256.
↑ Plavchan, Peter; et al. (June 2009), "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope", The Astrophysical Journal, 698 (2): 1068–1094, arXiv:0904.0819, Bibcode:2009ApJ...698.1068P, doi:10.1088/0004-637X/698/2/1068, S2CID 51417657.
1 2 3 4 Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A.; Costa, Edgardo (2024-06-24). "Speckle Interferometry at SOAR Telescope in 2023". The Astronomical Journal. 168 (1): 28. arXiv:2405.10071. doi:10.3847/1538-3881/ad4d56. ISSN 0004-6256.
↑ "Theta Indi". SIMBAD Astronomical Database. Retrieved 2016-08-23.
↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976 Vizier catalog entry
↑ Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920 Vizier catalog entry
↑ Marion, L.; Absil, O.; Ertel, S.; Le Bouquin, J.-B.; Defrère, D. (July 2014). "Unveiling new stellar companions from the PIONIER exozodi survey". In Rajagopal, Jayadev K; Creech-Eakman, Michelle J; Malbet, Fabien (eds.). Optical and Infrared Interferometry IV. Proceedings of the SPIE. Vol. 9146. pp. 91461K. arXiv:1410.5714. Bibcode:2014SPIE.9146E..1KM. doi:10.1117/12.2057823. S2CID 54045048.

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[XHIP-1] 1 2 3 4 5 6 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry

[dr3-2] 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[Gray2003-3] Gray, R. O.; Garrison, R. F. (July 1989), "The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation", Astrophysical Journal Supplement Series, 70 (4): 623–636, Bibcode:1989ApJS...70..623G, doi:10.1086/191349

[Wilson1953-4] Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W, LCCN 54001336

[Tuchow2024-5] 1 2 3 4 5 6 Tuchow, Noah W.; Stark, Christopher C.; Mamajek, Eric (2024-02-29). "HPIC: The Habitable Worlds Observatory Preliminary Input Catalog". The Astronomical Journal. 167 (3): 139. arXiv:2402.08038. doi:10.3847/1538-3881/ad25ec. ISSN 0004-6256.

[Plavchan2009-6] Plavchan, Peter; et al. (June 2009), "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope", The Astrophysical Journal, 698 (2): 1068–1094, arXiv:0904.0819, Bibcode:2009ApJ...698.1068P, doi:10.1088/0004-637X/698/2/1068, S2CID 51417657.

[Tokovinin2024-7] 1 2 3 4 Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A.; Costa, Edgardo (2024-06-24). "Speckle Interferometry at SOAR Telescope in 2023". The Astronomical Journal. 168 (1): 28. arXiv:2405.10071. doi:10.3847/1538-3881/ad4d56. ISSN 0004-6256.

[SIMBAD-8] "Theta Indi". SIMBAD Astronomical Database. Retrieved 2016-08-23.

[Eggleton2008-9] Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976 Vizier catalog entry

[WDS-10] Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920 Vizier catalog entry

[Marion2014-11] Marion, L.; Absil, O.; Ertel, S.; Le Bouquin, J.-B.; Defrère, D. (July 2014). "Unveiling new stellar companions from the PIONIER exozodi survey". In Rajagopal, Jayadev K; Creech-Eakman, Michelle J; Malbet, Fabien (eds.). Optical and Infrared Interferometry IV. Proceedings of the SPIE. Vol. 9146. pp. 91461K. arXiv:1410.5714. Bibcode:2014SPIE.9146E..1KM. doi:10.1117/12.2057823. S2CID 54045048.