TYC 1031-1262-1

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TYC 1031-1262-1
Hercules constellation map.svg
Red circle.svg
Location of TYC 1031-1262-1 (circled)
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]
PrimaryTYC 1031-1262-1 A
CompanionTYC 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☉
Luminosity109±26  L☉
Surface gravity (log g)2.057+0.040
−0.044  cgs
Temperature 4890±125  K
Other designations
Gaia DR3 4484245443888652032, TIC 287553455, TYC 1031-1262-1, GSC 01031-01262, 2MASS J18261150+1212349, ASAS J182611+1212.6, USNO-B1.0 1022-00398518 [4]
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]

Contents

A light curve for TYC 1031-1262-1, adapted from Antipin et al.. The upper plot shows the variability due to pulsations, with the orbit-related variability removed, and the lower plot shows orbit-related variability, with the pulsation effects removed. TYC1031-01262-1LightCurve.png
A light curve for TYC 1031-1262-1, adapted from Antipin et al.. The upper plot shows the variability due to pulsations, with the orbit-related variability removed, and the lower plot shows orbit-related variability, with the pulsation effects removed.

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

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

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

Footnotes

  1. ↑ Despite giving both stars the luminosity class II, Sipahi et al. (2013) [2] simultaneously refers to both stars as supergiants in their conclusion.

References

  1. 1 2 3 4 5 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.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 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. arXiv: 1211.1200 . doi: 10.1093/mnras/sts369 . ISSN   1365-2966.
  3. 1 2 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.
  4. ↑ "TYC 1031-1262-1". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 8 December 2024.
  5. ↑ North, Gerald; James, Nick (2014). Observing Variable Stars, Novae and Supernovae. Cambridge University Press. p. 24. ISBN   978-1-107-63612-5.
  6. 1 2 3 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. arXiv: 0705.0605 . Bibcode:2007MNRAS.379L..60A. doi: 10.1111/j.1745-3933.2007.00335.x . ISSN   1745-3933.
  7. ↑ Khruslov, A. V. (April 2008). "Pulsations in the Eclipsing Binary NSV 10993". Peremennye Zvezdy. 28 (4). Bibcode:2008PZ.....28....4K.
  8. ↑ 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.
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