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HD 178845 - Wikipedia

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HD 178845
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Location of HD 178845 (circled)
Constellation	Telescopium
A
Right ascension	19^h 12^m 46.13847^s^[1]
Declination	−50° 29′ 11.1095″^[1]
Apparent magnitude (V)	6.13^[2]
B
Right ascension	19^h 12^m 45.51968^s^[3]
Declination	−50° 29′ 08.7448″^[3]
Apparent magnitude (V)	10.90±0.02^[4]
Characteristics
A
Spectral type	G8 III^[5]
B−V color index	+0.95^[2]
Astrometry
A
Radial velocity (R_v)	−26.4±0.4^[6] km/s
Proper motion (μ)	RA: +44.868 mas/yr^[1] Dec.: −42.034 mas/yr^[1]
Parallax (π)	8.6125 ± 0.0283 mas^[1]
Distance	379 ± 1 ly (116.1 ± 0.4 pc)
Absolute magnitude (M_V)	+0.68^[7]
B
Radial velocity (R_v)	−24.2±5.3^[8] km/s
Proper motion (μ)	RA: +46.984 mas/yr^[3] Dec.: −41.403 mas/yr^[3]
Parallax (π)	8.6162 ± 0.024 mas^[3]
Distance	379 ± 1 ly (116.1 ± 0.3 pc)
Details^[9]
A
Mass	2.35±0.08 `M`_☉
Radius	9.13±0.16 `R`_☉
Luminosity	47±0.9 `L`_☉
Surface gravity (log g)	2.95±0.10 cgs
Temperature	5,001±36 K
Metallicity [Fe/H]	+0.02±0.03 dex
Rotational velocity (v sin i)	2.6±1.1^[10] km/s
Age	455⁺⁴⁵ ₋₄₆^[1] Myr

Other designations
49 G. Telescopii [11], CD−50°12377, CPD−50°10995, HD 178845, HIP 94398, HR 7271, SAO 245976, CCDM J19128-5029AB, WDS J19128-5029A
Database references
SIMBAD	data

HD 178845, also known as HR 7271 or rarely 49 G. Telescopii, is a binary star located in the southern constellation Telescopium. Gaia DR3 parallax measurements place the system 379 light years away^[3]^[1] and both components are approaching the Solar System with heliocentric radial velocities of −26 km/s and −24 km/s respectively.^[6]^[8] At its current distance, HD 178845A's brightness is diminished by 0.22 magnitudes due to interstellar dust.^[12]

The primary has an apparent magnitude of 6.13,^[2] placing it near the naked eye viewing limit and the companion has an apparent magnitude of 10.9,^[4] making it readily visible in medium-sized telescopes. The system was first observed by astronomer Willem Hendrik van den Bos in 1930.^[13] As of 1991, HD 178845B is located 7.2" away along a position angle of 320°.^[14]

The primary is an evolved red giant with a stellar classification of G8 III.^[5] It has 2.35 times the mass of the Sun^[9] but at the age of 455 million years,^[1] it has expanded to 9.1 times its radius.^[9] It radiates 47 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,001 K,^[9] giving it a yellow hue. It has a solar metallicity ([Fe/H] = +0.02^[9]) and spins modestly with a projected rotational velocity of 2.6 km/s.^[10]

References

^ ^a ^b ^c ^d ^e ^f ^g 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.
^ ^a ^b ^c Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
^ ^a ^b ^c ^d ^e 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.
^ ^a ^b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
^ ^a ^b Houk, Nancy (1978). Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40°. Vol. 2. Bibcode:1978mcts.book.....H.
^ ^a ^b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
^ 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
^ ^a ^b 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 ^d ^e Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Lovis, C.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V.; Marmier, M.; Mayor, M.; Santos, N. C.; Sousa, S. G.; Lagarde, N.; Charbonnel, C. (January 2022). "CORALIE radial-velocity search for companions around evolved stars (CASCADES): I. Sample definition and first results: Three new planets orbiting giant stars". Astronomy & Astrophysics. 657: A87. arXiv:2201.01528. Bibcode:2022A&A...657A..87O. doi:10.1051/0004-6361/202040078. eISSN 1432-0746. ISSN 0004-6361.
^ ^a ^b De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars V: Southern stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. eISSN 1432-0746. ISSN 0004-6361. S2CID 54046583.
^ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
^ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711.
^ van den Bos, W. H. (May 1930). "New southern double stars, tenth list". Bulletin of the Astronomical Institutes of the Netherlands. 5: 179. Bibcode:1930BAN.....5..179V. ISSN 0365-8910.
^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (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. ISSN 0004-6256.

Constellation of Telescopium

Stars

Bayer	α δ¹ δ² ε ζ η ι κ λ μ ν ξ ρ τ
Variable	RR RS RX BL HO PV PW PZ QQ QS QU QV
HR	6778 6821 6894 6954 6986 7065 7092 7093 7095 7097 7190 7223 7233 7271 7289 7297 7370 7388 7411 7459 7521 7537 7548 7549 7621 7674 7714 7745 7749 7758 7766
HD	168871 173047 177365 181295 191760
Other	KELT-10 Gliese 754 Gliese 784 GJ 1252

Exoplanets	Gliese 754 b Gliese 784 b GJ 1252 b KELT-10b

Star clusters	NGC 6584

Galaxies

NGC	6845 6861
Other	PKS 2014-55