MT Pegasi

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MT Pegasi
Observation data
Epoch J2000       Equinox J2000
Constellation Pegasus
Right ascension 23h 03m 04.977s [1]
Declination +20° 55′ 06.86″ [1]
Apparent magnitude  (V)6.616 [2]
Characteristics
Spectral type G1 V [3]
U−B color index +0.115 [2]
B−V color index +0.633 [4]
Variable type BY Dra [5]
Astrometry
Radial velocity (Rv)+2.084±0.005 [6]  km/s
Proper motion (μ)RA: −117.123  mas/yr [1]
Dec.: −28.530  mas/yr [1]
Parallax (π)41.1604 ± 0.0232  mas [1]
Distance 79.24 ± 0.04  ly
(24.30 ± 0.01  pc)
Absolute magnitude  (MV)4.65±0.03 [2]
Details [7]
Mass 1.066+0.020
−0.030  M☉
Radius 1.01+0.04
−0.02  R☉
Luminosity 1.07+0.12
−0.10  L☉
Surface gravity (log g)4.47+0.02
−0.04  cgs
Temperature 5,885±44  K
Metallicity [Fe/H]−0.03±0.03 [4]   dex
Rotation 5.82±1.47 days [8]
Rotational velocity (v sin i)3.2±0.05 km/s
Age 1.20+2.16
−1.20  Gyr
Other designations
MT Peg, BD+20° 5264, HD  217813, HIP  113829, SAO  90973 [9]
Database references
SIMBAD data

MT Pegasi is a single, [10] yellow-hued star in the northern constellation of Pegasus. It has the designation HD 217813 in the Henry Draper Catalogue ; MT Pegasi is the variable star designation. [9] With an apparent visual magnitude of 6.616, [2] it is a dim star that is at or below the nominal limit for visibility with the naked eye. Based upon an annual parallax shift of 41.16  mas [1] as measured from Earth's orbit, it is located 79.24  light years away. This star is a member of the Ursa Major Moving Group, a collection of stars that originated in the same open cluster and now share a common motion through space. [11]

This is a G-type main-sequence star with a stellar classification of G1 V. [3] Harlan and Taylor (1970) had assigned it a class of G5 V, [12] but this gives a poor match to the color index. [13] HD 217813 was found to be variable in 1995 and hence it was given the variable star designation MT Pegasi (MT Peg). It displays brightness variations with a period of several days, which is caused by star spots that are modulated by the star's rotation period. [13] MT Peg is classified as a BY Draconis variable. [5]

MT Peg is considered a young solar analog, which means it is a solar-type star representative of how a young, more active Sun may have appeared when it was less than 1.5 billion years old. [8] The estimated age based upon the chromospheric activity level is 397 million years, per Gray et al. (2015). [8] Marsden et al. (2014) gave a larger age estimate of 1.2 billion years, but with a margin of error that overlaps the younger value. [7] Age estimates of the Ursa Major group are around 300 million years old. [11]

The star has 1.07 times the mass of the Sun and 1.01 times the Sun's radius. [7] It is spinning with a projected rotational velocity of 3.2 km/s, [7] giving it a rotation period of 5.8 days. [8] The elemental composition of the stellar atmosphere is similar to the Sun. MT Peg is radiating 1.07 times the Sun's luminosity from its photosphere at an effective temperature of 5,885 K. [7]

Related Research Articles

51 Pegasi, formally named Helvetios, is a Sun-like star located 50.6 light-years from Earth in the constellation of Pegasus. It was the first main-sequence star found to have an exoplanet orbiting it.

HD 4308 is a single star in the southern constellation of Tucana. It has a yellow hue and is a challenge to view with the naked eye even under good seeing conditions, having an apparent visual magnitude of 6.54. This object is located at a distance of 72 light years, as determined from parallax measurements. It is a population II star and is considered to be a member of the thick disk. The star is receding from the Sun with a radial velocity of +95 km/s.

HD 196050 is a triple star system located in the southern constellation of Pavo. This system has an apparent magnitude of 7.50 and the absolute magnitude is 4.01. It is located at a distance of 165 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +61 km/s. It is also called by the Hipparcos designation HIP 101806.

<span class="mw-page-title-main">HD 17925</span> Star in the constellation Eridanus

HD 17925 is a variable star in the equatorial constellation of Eridanus. It has the Gould designation 32 G. Eridani and the variable star designation EP Eri. The star has a yellow-orange hue and is dimly visible to the naked eye in good seeing conditions with an apparent visual magnitude that varies from 6.03 down to 6.08. It is located nearby at a distance of 34 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +18 km/s. It is a likely member of the Local Association of nearby, co-moving stars. The spectrum shows a strong abundance of lithium, indicating that it is young star. This likely makes its point of origin the nearby Scorpio–Centaurus Complex.

HD 24496 is a binary star system in the equatorial constellation of Taurus. The combined apparent visual magnitude of the pair is 6.81, which is too faint to be readily visible to the normal human eye. The system is located at a distance of 66.8 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +19 km/s. It is traversing the celestial sphere with a proper motion of 0.276″ per year.

<span class="mw-page-title-main">111 Tauri</span> Wide binary star system in the constellation Taurus

111 Tauri is a wide binary star system in the constellation Taurus. It is located at a distance of 48 light years from the Sun. Primary component A is a main sequence star with a stellar classification of F8V. The secondary component B is a K-type main sequence star. The primary is larger and more luminous than the Sun, with about 130% of the Sun's radius and 185% of the Sun's luminosity. The apparent magnitude of 5.0 indicates it is a faint star that can be viewed by the naked eye under good, dark-sky conditions.

HD 114837 is a suspected binary star system in the southern constellation of Centaurus. The brighter star is faintly visible to the naked eye with an apparent visual magnitude of 4.90. It has a magnitude 10.2 candidate common proper motion companion at an angular separation of 4.2″, as of 2014. The distance to this system, based on an annual parallax shift of 55.0143″ as seen from Earth's orbit, is 59.3 light years. It is moving closer with a heliocentric radial velocity of −64 km/s, and will approach to within 21.8 ly in around 240,600 years.

Pi<sup>2</sup> Pegasi Single star in the constellation Pegasus

π2 Pegasi, Latinized as Pi2 Pegasi, is a single star in the northern constellation Pegasus. It is yellow-white in hue and visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.28. The distance to this object is approximately 263 light years based on parallax, and it is drifting further away with a radial velocity of +5 km/s. This star is an outlying member of the Ursa Major Moving Group.

<span class="mw-page-title-main">56 Pegasi</span> Star in the constellation Pegasus

56 Pegasi is a binary star system in the northern constellation of Pegasus. It is visible to the naked eye with a combined apparent visual magnitude of 4.74. The system is approximately 590 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −28 km/s. It is listed as a member of the Wolf 630 moving group.

<span class="mw-page-title-main">Chi Pegasi</span> Red giant star in the constellation Pegasus

Chi Pegasi, Latinised from χ Pegasi, is a single star in the northern constellation of Pegasus, along the eastern constellation border with Pisces. It has a reddish hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.80. The distance to this star is approximately 368 light-years based on parallax, but it is drifting closer with a radial velocity of −46 km/s.

<span class="mw-page-title-main">Nu Pegasi</span> Star in the constellation Pegasus

ν Pegasi, Latinized as Nu Pegasi is a single star in the northern constellation of Pegasus. It is an orange-hued star that is faintly visible to the naked eye with an apparent visual magnitude of 4.84. The star is located approximately 261 light years away based on parallax, but is drifting closer with a radial velocity of −19 km/s.

33 Pegasi is the Flamsteed designation for a visual binary star in the northern constellation of Pegasus. It has an apparent visual magnitude of 6.2, placing it near the limit of naked eye visibility. Measurements show an annual parallax shift of 0.0298125″, which is equivalent to a distance of 109 ly (33 pc) from the Sun. It is drifting further away with a radial velocity of 24 km/s.

<span class="mw-page-title-main">Phi Pegasi</span> Variable star in the constellation Pegasus

φ Pegasi, Latinised as Phi Pegasi, is a solitary, reddish hued star in the northern constellation of Pegasus. With an apparent visual magnitude of around 5.1, it is a faint star that can be seen with the naked eye. Based upon an annual parallax shift of 7.05 mas as seen from Earth, the system is located around 460 light years distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.15 due to interstellar dust.

<span class="mw-page-title-main">HN Pegasi</span> Star in the constellation Pegasus

HN Pegasi is the variable star designation for a young, Sun-like star in the northern constellation of Pegasus. It has an apparent visual magnitude of 5.9, which, according to the Bortle scale, indicates that it is visible to the naked eye from suburban skies. Parallax measurements put the star at a distance of around 59 light years from the Sun, but it is drifting closer with a radial velocity of −16.7 km/s.

<span class="mw-page-title-main">9 Ceti</span> Star in the constellation Cetus

9 Ceti is a star in the equatorial constellation of Cetus. It has the variable star designation BE Ceti, while 9 Ceti is the Flamsteed designation. It has an apparent visual magnitude of 6.4, which is below the limit that can be seen with the naked eye by a typical observer. Based upon parallax measurements, this star is 69.6 light years away from the Sun.

HD 189245 is the Henry Draper catalogue designation for a solitary star in the southern constellation of Sagittarius. It has an apparent visual magnitude of 5.66, which means it is faintly visible to the naked eye. Parallax measurements from the Hipparcos satellite indicate a distance of 72 light years from the Sun. It is drifting closer with a heliocentric radial velocity of −13 km/s.

<span class="mw-page-title-main">DY Pegasi</span> Star in the constellation Pegasus

DY Pegasi, abbreviated DY Peg, is a binary star system in the northern constellation of Pegasus. It is a well-studied SX Phoenicis variable star with a brightness that ranges from an apparent visual magnitude of 9.95 down to 10.62 with a period of 1.75 hours. This system is much too faint to be seen with the naked eye, but can be viewed with large binoculars or a telescope. Based on its high space motion and low abundances of heavier elements, it is a population II star system.

<span class="mw-page-title-main">57 Pegasi</span> Binary star in the constellation Pegasus

57 Pegasi is a variable binary star system in the northern constellation of Pegasus (constellation). It has the variable star designation GZ Pegasi, while 57 Pegasi is the Flamsteed designation. The system is faintly visible to the naked eye as a point of light with an apparent visual magnitude that fluctuates around 5.105. It is located at a distance of approximately 780 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +14 km/s.

<span class="mw-page-title-main">LO Pegasi</span> Star in the constellation Pegasus

LO Pegasi is a single star in the northern constellation of Pegasus that has been the subject of numerous scientific studies. LO Pegasi, abbreviated LO Peg, is the variable star designation. It is too faint to be viewed with the naked eye, having an apparent visual magnitude that ranges from 9.04 down to 9.27. Based on parallax measurements, LO Peg is located at a distance of 79 light years from the Sun. It is a member of the young AB Doradus moving group, and is drifting closer with a radial velocity of −23 km/s.

HD 1032 is a solitary star in the southern circumpolar constellation Octans. It is faintly visible to the naked eye with an apparent magnitude of 5.77 and is estimated to be 850 light years away from the Solar System based on parallax measure. However, it is receding with a heliocentric radial velocity of 4 km/s.

References

  1. 1 2 3 4 5 6 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 Koen, C.; Kilkenny, D.; van Wyk, F.; Marang, F. (2010), "UBV(RI)C JHK observations of Hipparcos-selected nearby stars", Monthly Notices of the Royal Astronomical Society , 403 (4): 1949–1968, Bibcode:2010MNRAS.403.1949K, doi: 10.1111/j.1365-2966.2009.16182.x .
  3. 1 2 Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal , 132 (1): 161–170, arXiv: astro-ph/0603770 , Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID   119476992.
  4. 1 2 Rich, Evan A.; et al. (December 2017), "The fundamental stellar parameters of FGK stars in the SEEDS survey", Monthly Notices of the Royal Astronomical Society, 472 (2): 1736–1752, arXiv: 1708.02541 , Bibcode:2017MNRAS.472.1736R, doi:10.1093/mnras/stx2051, S2CID   58942857.
  5. 1 2 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869.
  6. ↑ Soubiran, C.; et al. (April 2013), "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release", Astronomy & Astrophysics, 552: 11, arXiv: 1302.1905 , Bibcode:2013A&A...552A..64S, doi:10.1051/0004-6361/201220927, S2CID   56094559, A64.
  7. 1 2 3 4 5 Marsden, S. C.; et al. (November 2014), "A BCool magnetic snapshot survey of solar-type stars", Monthly Notices of the Royal Astronomical Society, 444 (4): 3517–3536, arXiv: 1311.3374 , Bibcode:2014MNRAS.444.3517M, doi:10.1093/mnras/stu1663, S2CID   53988884.
  8. 1 2 3 4 Gray, R. O.; et al. (December 2015), "The Young Solar Analogs Project. I. Spectroscopic and Photometric Methods and Multi-year Timescale Spectroscopic Results", The Astronomical Journal, 150 (6): 19, arXiv: 1511.00279 , Bibcode:2015AJ....150..203G, doi:10.1088/0004-6256/150/6/203, S2CID   119286603, 203.
  9. 1 2 "HD 217813". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2018-08-15.
  10. ↑ Fuhrmann, K.; et al. (2017), "Multiplicity among Solar-type Stars", The Astrophysical Journal, 836 (1): 139, Bibcode:2017ApJ...836..139F, doi: 10.3847/1538-4357/836/1/139 .
  11. 1 2 Ammler, M.; Guenther, E. W.; König, B.; Neuhäuser, R. (March 2005), "High-resolution spectroscopy of the UMa group", in Favata, F.; Hussain, G. A. J.; Battrick, B. (eds.), Proceedings of the 13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, held 5-9 July, 2004 in Hamburg, Germany, vol. 560, European Space Agency, p. 391, Bibcode:2005ESASP.560..391A
  12. ↑ Harlan, E. A.; Taylor, D. C. (March 1970), "MK classifications for F-and G-type stars. II", Astronomical Journal, 75: 165–166, Bibcode:1970AJ.....75..165H, doi: 10.1086/110956 .
  13. 1 2 Depasquale, J. M.; et al. (August 2000), "MT Pegasi (= HD 217813) - A Young Sun with Starspots", Information Bulletin on Variable Stars, 4933: 1, Bibcode:2000IBVS.4933....1D.
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