TYC 1031-1262-1
  | |
| Observation data Epoch J2000[1] Equinox J2000[1] | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 26m 11.50390s |
| Declination | +12° 12′ 34.9356″ |
| Apparent magnitude (V) | 11.64[2] |
| Characteristics | |
| Spectral type | F8II + G6II[2] |
| B−V color index | +0.77[2] |
| J−H color index | +0.368[3] |
| J−K color index | +0.473[3] |
| Variable type | Eclipsing binary, Type II Cepheid (A)[2] |
| Astrometry | |
| Proper motion (μ) | RA: 1.692[1] mas/yr Dec.: 0.469[1] mas/yr |
| Parallax (π) | 0.3836 ± 0.0177 mas[1] |
| Distance | 5070±250[2] pc |
| Orbit[2] | |
| Primary | TYC 1031-1262-1 A |
| Companion | TYC 1031-1262-1 B |
| Period (P) | 51.2857±0.0174 d |
| Semi-major axis (a) | 79.58±2.54 R☉ (0.3701±0.0118 AU) |
| Eccentricity (e) | 0.001±0.001 |
| Inclination (i) | 74.0±0.4° |
| Semi-amplitude (K1) (primary) | 27.4±1.7 km/s |
| Semi-amplitude (K2) (secondary) | 48.1±1.7 km/s |
| Details[2] | |
| TYC 1031-1262-1 A | |
| Mass | 1.640±0.151 M☉ |
| Radius | 26.9±0.9 R☉ |
| Luminosity | 764±144 L☉ |
| Surface gravity (log g) | 1.792±0.021 cgs |
| Temperature | 5880±200 K |
| TYC 1031-1262-1 B | |
| Mass | 0.934±0.109 M☉ |
| Radius | 15.0±0.7 R☉ |
| Luminosity | 109±26 L☉ |
| Surface gravity (log g) | 2.057+0.040 −0.044 cgs |
| Temperature | 4890±125 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
TYC 1031-1262-1 is a spectroscopic binary[2] in the northern constellation of Hercules, near the border with Ophiuchus, approximately 5,070 parsecs (16,500 light-years) distant. With an apparent magnitude of 11.64, it is too faint to be seen by the naked eye, but is observable using a telescope with an aperture of 60 mm (2.4 in) or larger.[5]
The star's variability was first detected in 2005. In 2007, it was reported as the first eclipsing binary system with a type II Cepheid component to be detected in the Milky Way. It also had the shortest period of any known Cepheid binary at that time.[6] A follow-up study in 2013, however, argues that the pulsating component is too massive to be a type II Cepheid and thus is instead an anomalous Cepheid, an object located between classical Cepheids and type II Cepheids in the Hertzsprung-Russell diagram.[2] A similar object, NSV 10993 (V1135 Herculis), was discovered in 2008.[7]
Physical properties
[edit]The two components are both evolved bright giants (luminosity class II), more luminous than normal giant stars but less so than supergiants.[a] The brighter of the pair (hereafter component "A") is the Cepheid that pulsates at a period of 4.15270 days, which is increasing at a rate of 2.46±0.54 min/yr for unknown reasons. It is 64% more massive than the Sun but has ballooned to 27 times the girth, radiating 764 times the luminosity of the Sun from its photosphere at an effective temperature of 5,880 K (5,610 °C; 10,120 °F), corresponding to its spectral type of F8II. Its dimmer G6II companion (B) is slightly less massive than the Sun and cooler at 4,890 K (4,620 °C; 8,340 °F), but has a radius 15 times larger and emits a little over 100 times the solar luminosity.[2]
A and B revolve around each other with an orbital period of 51.2857 days at a distance of 0.3701 AU (55,370,000 km), only twice the sum of their radii. As a result of this close proximity, the pulsation and evolution of A has been affected. Furthermore, A fills nearly 85% of its Roche lobe, while B occupies 61%, meaning that a loss or transfer of mass has likely occurred from A.[2] The amplitude of the brightness changes caused by one star eclipsing the other is relatively small, which implies that the two stars only partially eclipse each other.[6]
The star is a member of the thick disk population, located 970 parsecs (3,200 ly) from the Galactic plane.[2]
Nearby objects
[edit]Follow-up observations on the star in 2008 revealed nine new variable stars in the immediate vicinity, including seven eclipsing binaries, one RR Lyrae variable, and one long-period, irregular or semiregular variable star.[8]
See also
[edit]- V1334 Cygni: a binary system containing a classical Cepheid variable.
Footnotes
[edit]References
[edit]- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c d e f g h i j k l m Sipahi, E.; İbanoǧlu, C.; Çakırlı, ö.; Evren, S. (11 February 2013). "TYC 1031 1262 1: an anomalous Cepheid in a double-lined eclipsing binary". Monthly Notices of the Royal Astronomical Society. 429 (1): 757–766. doi:10.1093/mnras/sts369. ISSN 1365-2966.
- ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ "TYC 1031-1262-1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 December 2024.
- ^ North, Gerald; James, Nick (2014). Observing Variable Stars, Novae and Supernovae. Cambridge University Press. p. 24. ISBN 978-1-107-63612-5.
- ^ a b c Antipin, S. V.; Sokolovsky, K. V.; Ignatieva, T. I. (1 July 2007). "TYC 1031 01262 1: the first known Galactic eclipsing binary with a Type II Cepheid component". Monthly Notices of the Royal Astronomical Society: Letters. 379 (1): L60–L62. doi:10.1111/j.1745-3933.2007.00335.x. ISSN 1745-3933.
- ^ Khruslov, A. V. (April 2008). "Pulsations in the Eclipsing Binary NSV 10993". Peremennye Zvezdy. 28 (4). Bibcode:2008PZ.....28....4K.
- ^ Sokolovsky, K. V.; Elenin, L. (November 2008). "New Variable Stars Discovered Using the Tzec Maun Observatory Telescopes". Peremennye Zvezdy Prilozhenie. 8 (42). Bibcode:2008PZP.....8...42S.
