| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 14h 57m 52.98352s [1] |
| Declination | −76° 39′ 45.5569″ [1] |
| Apparent magnitude (V) | 5.36±0.01 [2] |
| Characteristics | |
| Spectral type | K4 III: [3] |
| B−V color index | +1.44 [4] |
| Variable type | constant [5] |
| Astrometry | |
| Radial velocity (Rv) | −31.20±0.08 [6] km/s |
| Proper motion (μ) |
RA: −69.161
mas/
yr
[1] Dec.: −16.583 mas/ yr [1] |
| Parallax (π) | 7.8879 ± 0.0867 mas [1] |
| Distance | 413 ± 5
ly (127 ± 1 pc) |
| Absolute magnitude (MV) | −0.22±0.16 [7] |
| Details | |
| Mass | 1.10±0.18 [6] M☉ |
| Radius | 30.1±1.5 [8] R☉ |
| Luminosity | 293+9 −10 [1] L☉ |
| Surface gravity (log g) | 1.62 [9] cgs |
| Temperature | 4282±33 [10] K |
| Metallicity [Fe/H] | −0.29±0.05 [6] dex |
| Rotational velocity (v sin i) | <1.3 [11] km/s |
| Age | 5.68±2.42 [6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
R Apodis (HD 131109; HR 5540; 18 G. Apodis) is a solitary star [13] in the constellation Apus. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.36. [2] Gaia DR3 parallax measurements imply a distance of 413 light-years [1] and it is drifting closer with a heliocentric radial velocity of −31.2 km/s. [6] At its current distance, R Apodis' brightness is diminished by an interstellar extinction of 0.26 magnitudes [14] and it has an absolute magnitude of −0.22. [7]
HD 131109 was the first star observed to be variable in the constellation; It was first discovered in 1873 by Benjamin Apthorp Gould. Later, it was hastily given the variable star designation R Apodis in a 1907 variable star catalogue despite it being a suspected variable star at the time. [15] However, observations conducted in a 1952 field star survey revealed that R Apodis was not variable at all. [16] Keenan & Pitts (1980) found that it varied between magnitudes 5.5 and 6.1, but this was never confirmed. [17] Hipparcos photometric data revealed that R Apodis indeed had a constant brightness. [18] It has since been listed as a class CST: in the General Catalog of Variable Stars. [5]
R Apodis has a stellar classification of K4 III:, [3] indicating that it is an evolved K-type giant that has ceased hydrogen fusion at its core and left the main sequence. However, there is uncertainty about the luminosity class. It has a comparable mass to the Sun but at the age of 5.68 billion years, [6] it has expanded to 30.1 times the radius of the Sun. [8] It radiates 293 times the luminosity of the Sun [1] from its enlarged photosphere at an effective temperature of 4,282 K. [10] R Apodis is metal deficient with an iron abundance roughly half of the Sun's [6] and it spins slowly with a projected rotational velocity lower than 1.3 km/s. [11]
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 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. S2CID 17128864.
- ^ a b Keenan, Philip C; McNeil, Raymond C (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode: 1989ApJS...71..245K. doi: 10.1086/191373.
- ^ Cousins, A. W. J. (1977). "Cape UBV magnitudes and colours of South circumpolar stars". South African Astronomical Observatory Circulars. 1: 51. Bibcode: 1977SAAOC...1...51C.
- ^ a b 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 d e f g Jofré, E; Petrucci, R; Saffe, C; Saker, L; de la Villarmois, E. Artur; Chavero, C; Gómez, M; Mauas, P. J. D (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv: 1410.6422. Bibcode: 2015A&A...574A..50J. doi: 10.1051/0004-6361/201424474. S2CID 53666931.
- ^ a b da Silva, L.; et al. (November 2006). "Basic physical parameters of a selected sample of evolved stars". Astronomy and Astrophysics. 458 (2): 609–623. arXiv: astro-ph/0608160. Bibcode: 2006A&A...458..609D. doi: 10.1051/0004-6361:20065105. S2CID 9341088.
- ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv: astro-ph/0404180. Bibcode: 2004A&A...426..297K. doi: 10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
- ^ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv: 1706.02208. Bibcode: 2017MNRAS.471..770M. doi: 10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711. S2CID 73594365.
- ^ a b Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv: 1905.10694. Bibcode: 2019AJ....158..138S. doi: 10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl: 1721.1/124721. S2CID 166227927.
- ^ 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.
- ^ Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
- ^ 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. S2CID 118879856.
- ^ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode: 1907AnHar..55....1C. S2CID 116966328.
- ^ Gaposchkin, Cecilia Helena Payne; Gaposchkin, Sergei; Menzel, Donald Howard (1952). "Variable stars in Milton field 54". Annals of Harvard College Observatory. 115: 1–10. Bibcode: 1952AnHar.115....1P.
- ^ Keenan, P. C.; Pitts, R. E. (April 1980). "Revised MK spectral types for G, K ANS M stars". The Astrophysical Journal Supplement Series. 42: 541–563. Bibcode: 1980ApJS...42..541K. doi: 10.1086/190662. ISSN 0067-0049.
- ^ Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; Hoeg, E.; Bastian, U.; Bernacca, P. L.; Crézé, M.; Donati, F.; Grenon, M.; Grewing, M.; van Leeuwen, F. (July 1997). "The HIPPARCOS Catalogue". Astronomy and Astrophysics. 323: L49–L52. Bibcode: 1997A&A...323L..49P. ISSN 0004-6361.
| Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 14h 57m 52.98352s [1] |
| Declination | −76° 39′ 45.5569″ [1] |
| Apparent magnitude (V) | 5.36±0.01 [2] |
| Characteristics | |
| Spectral type | K4 III: [3] |
| B−V color index | +1.44 [4] |
| Variable type | constant [5] |
| Astrometry | |
| Radial velocity (Rv) | −31.20±0.08 [6] km/s |
| Proper motion (μ) |
RA: −69.161
mas/
yr
[1] Dec.: −16.583 mas/ yr [1] |
| Parallax (π) | 7.8879 ± 0.0867 mas [1] |
| Distance | 413 ± 5
ly (127 ± 1 pc) |
| Absolute magnitude (MV) | −0.22±0.16 [7] |
| Details | |
| Mass | 1.10±0.18 [6] M☉ |
| Radius | 30.1±1.5 [8] R☉ |
| Luminosity | 293+9 −10 [1] L☉ |
| Surface gravity (log g) | 1.62 [9] cgs |
| Temperature | 4282±33 [10] K |
| Metallicity [Fe/H] | −0.29±0.05 [6] dex |
| Rotational velocity (v sin i) | <1.3 [11] km/s |
| Age | 5.68±2.42 [6] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
R Apodis (HD 131109; HR 5540; 18 G. Apodis) is a solitary star [13] in the constellation Apus. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.36. [2] Gaia DR3 parallax measurements imply a distance of 413 light-years [1] and it is drifting closer with a heliocentric radial velocity of −31.2 km/s. [6] At its current distance, R Apodis' brightness is diminished by an interstellar extinction of 0.26 magnitudes [14] and it has an absolute magnitude of −0.22. [7]
HD 131109 was the first star observed to be variable in the constellation; It was first discovered in 1873 by Benjamin Apthorp Gould. Later, it was hastily given the variable star designation R Apodis in a 1907 variable star catalogue despite it being a suspected variable star at the time. [15] However, observations conducted in a 1952 field star survey revealed that R Apodis was not variable at all. [16] Keenan & Pitts (1980) found that it varied between magnitudes 5.5 and 6.1, but this was never confirmed. [17] Hipparcos photometric data revealed that R Apodis indeed had a constant brightness. [18] It has since been listed as a class CST: in the General Catalog of Variable Stars. [5]
R Apodis has a stellar classification of K4 III:, [3] indicating that it is an evolved K-type giant that has ceased hydrogen fusion at its core and left the main sequence. However, there is uncertainty about the luminosity class. It has a comparable mass to the Sun but at the age of 5.68 billion years, [6] it has expanded to 30.1 times the radius of the Sun. [8] It radiates 293 times the luminosity of the Sun [1] from its enlarged photosphere at an effective temperature of 4,282 K. [10] R Apodis is metal deficient with an iron abundance roughly half of the Sun's [6] and it spins slowly with a projected rotational velocity lower than 1.3 km/s. [11]
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 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. S2CID 17128864.
- ^ a b Keenan, Philip C; McNeil, Raymond C (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode: 1989ApJS...71..245K. doi: 10.1086/191373.
- ^ Cousins, A. W. J. (1977). "Cape UBV magnitudes and colours of South circumpolar stars". South African Astronomical Observatory Circulars. 1: 51. Bibcode: 1977SAAOC...1...51C.
- ^ a b 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 d e f g Jofré, E; Petrucci, R; Saffe, C; Saker, L; de la Villarmois, E. Artur; Chavero, C; Gómez, M; Mauas, P. J. D (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv: 1410.6422. Bibcode: 2015A&A...574A..50J. doi: 10.1051/0004-6361/201424474. S2CID 53666931.
- ^ a b da Silva, L.; et al. (November 2006). "Basic physical parameters of a selected sample of evolved stars". Astronomy and Astrophysics. 458 (2): 609–623. arXiv: astro-ph/0608160. Bibcode: 2006A&A...458..609D. doi: 10.1051/0004-6361:20065105. S2CID 9341088.
- ^ a b Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (April 8, 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv: astro-ph/0404180. Bibcode: 2004A&A...426..297K. doi: 10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361. S2CID 6077801.
- ^ McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv: 1706.02208. Bibcode: 2017MNRAS.471..770M. doi: 10.1093/mnras/stx1433. eISSN 1365-2966. ISSN 0035-8711. S2CID 73594365.
- ^ a b Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv: 1905.10694. Bibcode: 2019AJ....158..138S. doi: 10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl: 1721.1/124721. S2CID 166227927.
- ^ 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.
- ^ Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711. S2CID 14878976.
- ^ 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. S2CID 118879856.
- ^ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode: 1907AnHar..55....1C. S2CID 116966328.
- ^ Gaposchkin, Cecilia Helena Payne; Gaposchkin, Sergei; Menzel, Donald Howard (1952). "Variable stars in Milton field 54". Annals of Harvard College Observatory. 115: 1–10. Bibcode: 1952AnHar.115....1P.
- ^ Keenan, P. C.; Pitts, R. E. (April 1980). "Revised MK spectral types for G, K ANS M stars". The Astrophysical Journal Supplement Series. 42: 541–563. Bibcode: 1980ApJS...42..541K. doi: 10.1086/190662. ISSN 0067-0049.
- ^ Perryman, M. A. C.; Lindegren, L.; Kovalevsky, J.; Hoeg, E.; Bastian, U.; Bernacca, P. L.; Crézé, M.; Donati, F.; Grenon, M.; Grewing, M.; van Leeuwen, F. (July 1997). "The HIPPARCOS Catalogue". Astronomy and Astrophysics. 323: L49–L52. Bibcode: 1997A&A...323L..49P. ISSN 0004-6361.