# HD 70573

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Star in the constellation Hydra

HD 70573 A light curve for V478 Hydrae, plotted from TESS data[1] Observation data Epoch J2000.0 Equinox J2000.0 Constellation Hydra Right ascension 08h 22m 49.95277s[2] Declination +01° 51′ 33.5522″[2] Apparent magnitude (V) 8.66-8.77[3] Characteristics Evolutionary stage main sequence[2] Spectral type G1/2V[4] B−V color index 0.59[5] Variable type BY Dra[3] Astrometry Radial velocity (Rv) 20.16±0.22[2] km/s Proper motion (μ) RA: −51.362±0.017 mas/yr[2] Dec.: −49.047±0.013 mas/yr[2] Parallax (π) 16.9267±0.0168 mas[2] Distance 192.7 ± 0.2 ly (59.08 ± 0.06 pc) Absolute magnitude (MV) +0.4[6] Details Mass 1.0±0.1[6] M☉ Radius 0.98+0.01 −0.03[7] R☉ Luminosity 0.998±0.004[7] L☉ Surface gravity (log g) 4.59±0.10[6] cgs Temperature 5,837+80 −51[7] K Metallicity [Fe/H] −0.18±0.20[6] dex Rotation 3.296 days[6] Rotational velocity (v sin i) 14.7±1.0[6] km/s Age 2.3±2.1[8] Gyr Other designations V478 Hya, BD+02°1951, HD 70573, SAO 116694[9] Database references SIMBAD data

**HD 70573** is a [variable star](/source/Variable_star) in the [equatorial](/source/Celestial_equator) [constellation](/source/Constellation) of [Hydra](/source/Hydra_(constellation)). At a mean [apparent visual magnitude](/source/Apparent_visual_magnitude) of +8.7, this yellow-hued star is too dim to be visible to the naked eye. Based upon [parallax](/source/Stellar_parallax) measurements, it is located at a distance of 193 [light years](/source/Light_year) from the [Sun](/source/Sun), and is drifting further away with a [radial velocity](/source/Radial_velocity) of 20.5 km/s. It is a candidate member of the proposed Hercules-Lyra Association of co-moving stars,[5] although this membership is disputed.[10]

This is a [G-type main-sequence star](/source/G-type_main-sequence_star) with a [stellar classification](/source/Stellar_classification) of G1/2V.[4] It is a [BY Draconis variable](/source/BY_Draconis_variable) that ranges in brightness from magnitude 8.66 down to 8.77 with a rotationally-modulated period of 3.296 days.[3] HD 70573 is generally considered to be a young star although estimates of its age vary from 60[11] million years to several billion years.[8] It has a [projected rotational velocity](/source/Projected_rotational_velocity) of 15 km/s[6] and about the same mass, size, and luminosity as the Sun.

## Planetary system

On March 19, 2007, an [extrasolar planet](/source/Extrasolar_planet) was announced, having been discovered by the [radial velocity](/source/Radial_velocity) method. As of 2007, this was the youngest host star discovered to have an orbiting planet.[6] However, a follow-up study by Soto et al. in 2015 failed to detect the planetary signal, so it remains unconfirmed.[12]

The system displays an [infrared excess](/source/Infrared_excess), which matches the [black body](/source/Black_body) signature of a [debris disk](/source/Debris_disk) orbiting 21.8 [AU](/source/Astronomical_unit) from the host star with a mean temperature of 60 K.[13]

The HD 70573 planetary system[6] Companion (in order from star) Mass Semimajor axis (AU) Orbital period (days) Eccentricity Inclination (°) Radius b (unconfirmed) ≥6.1±0.4 MJ 1.76±0.05 851.8±11.6 0.4±0.1 — —

## References

1. **[^](#cite_ref-MAST_1-0)** ["MAST: Barbara A. Mikulski Archive for Space Telescopes"](https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html). Space Telescope Science Institute. Retrieved 8 December 2021.

1. ^ [***a***](#cite_ref-GaiaDR3_2-0) [***b***](#cite_ref-GaiaDR3_2-1) [***c***](#cite_ref-GaiaDR3_2-2) [***d***](#cite_ref-GaiaDR3_2-3) [***e***](#cite_ref-GaiaDR3_2-4) [***f***](#cite_ref-GaiaDR3_2-5) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D3090083696499829376%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Samus2017_3-0) [***b***](#cite_ref-Samus2017_3-1) [***c***](#cite_ref-Samus2017_3-2) Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". *Astronomy Reports*. 5.1. **61** (1): 80–88. [Bibcode](/source/Bibcode_(identifier)):[2017ARep...61...80S](https://ui.adsabs.harvard.edu/abs/2017ARep...61...80S). [doi](/source/Doi_(identifier)):[10.1134/S1063772917010085](https://doi.org/10.1134%2FS1063772917010085). [S2CID](/source/S2CID_(identifier)) [125853869](https://api.semanticscholar.org/CorpusID:125853869).

1. ^ [***a***](#cite_ref-Houk1999_4-0) [***b***](#cite_ref-Houk1999_4-1) Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". *Michigan Spectral Survey*. **5**. [Bibcode](/source/Bibcode_(identifier)):[1999MSS...C05....0H](https://ui.adsabs.harvard.edu/abs/1999MSS...C05....0H).

1. ^ [***a***](#cite_ref-Lopez2006_5-0) [***b***](#cite_ref-Lopez2006_5-1) López-Santiago, J.; et al. (2006). "The Nearest Young Moving Groups". *The Astrophysical Journal*. **643** (2): 1160–1165. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0601573](https://arxiv.org/abs/astro-ph/0601573). [Bibcode](/source/Bibcode_(identifier)):[2006ApJ...643.1160L](https://ui.adsabs.harvard.edu/abs/2006ApJ...643.1160L). [doi](/source/Doi_(identifier)):[10.1086/503183](https://doi.org/10.1086%2F503183). [S2CID](/source/S2CID_(identifier)) [119520529](https://api.semanticscholar.org/CorpusID:119520529).

1. ^ [***a***](#cite_ref-Setiawan2007_6-0) [***b***](#cite_ref-Setiawan2007_6-1) [***c***](#cite_ref-Setiawan2007_6-2) [***d***](#cite_ref-Setiawan2007_6-3) [***e***](#cite_ref-Setiawan2007_6-4) [***f***](#cite_ref-Setiawan2007_6-5) [***g***](#cite_ref-Setiawan2007_6-6) [***h***](#cite_ref-Setiawan2007_6-7) [***i***](#cite_ref-Setiawan2007_6-8) Setiawan; et al. (2007). "Evidence for a Planetary Companion around a Nearby Young Star". *The Astrophysical Journal Letters*. **660** (2): L145–L148. [arXiv](/source/ArXiv_(identifier)):[0704.0441](https://arxiv.org/abs/0704.0441). [Bibcode](/source/Bibcode_(identifier)):[2007ApJ...660L.145S](https://ui.adsabs.harvard.edu/abs/2007ApJ...660L.145S). [doi](/source/Doi_(identifier)):[10.1086/518213](https://doi.org/10.1086%2F518213). [S2CID](/source/S2CID_(identifier)) [18721503](https://api.semanticscholar.org/CorpusID:18721503).

1. ^ [***a***](#cite_ref-GaiaDR2_7-0) [***b***](#cite_ref-GaiaDR2_7-1) [***c***](#cite_ref-GaiaDR2_7-2) [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. ([Gaia collaboration](/source/Data_Processing_and_Analysis_Consortium)) (August 2018). ["*Gaia* Data Release 2: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F201833051). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **616**. A1. [arXiv](/source/ArXiv_(identifier)):[1804.09365](https://arxiv.org/abs/1804.09365). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...616A...1G](https://ui.adsabs.harvard.edu/abs/2018A&A...616A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201833051](https://doi.org/10.1051%2F0004-6361%2F201833051). [Gaia DR2 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20DR2%203090083696499829376) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-LDA2021_8-0) [***b***](#cite_ref-LDA2021_8-1) Llorente de Andrés, F.; Chavero, C.; de la Reza, R.; Roca-Fàbrega, S.; Cifuentes, C. (October 2021). ["The evolution of lithium in FGK dwarf stars. The lithium-rotation connection and the Li desert"](https://doi.org/10.1051%2F0004-6361%2F202141339). *Astronomy and Astrophysics*. **654**: A137. [arXiv](/source/ArXiv_(identifier)):[2108.05852](https://arxiv.org/abs/2108.05852). [Bibcode](/source/Bibcode_(identifier)):[2021A&A...654A.137L](https://ui.adsabs.harvard.edu/abs/2021A&A...654A.137L). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202141339](https://doi.org/10.1051%2F0004-6361%2F202141339). [ISSN](/source/ISSN_(identifier)) [0004-6361](https://search.worldcat.org/issn/0004-6361).

1. **[^](#cite_ref-SIMBAD_9-0)** ["HD 70573"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+70573). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2020-01-08.

1. **[^](#cite_ref-Eisenbeiss2013_10-0)** Eisenbeiss, T.; et al. (August 2013). "The Hercules-Lyra association revisited. New age estimation and multiplicity study". *Astronomy & Astrophysics*. **556**: 19. [arXiv](/source/ArXiv_(identifier)):[1312.4045](https://arxiv.org/abs/1312.4045). [Bibcode](/source/Bibcode_(identifier)):[2013A&A...556A..53E](https://ui.adsabs.harvard.edu/abs/2013A&A...556A..53E). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201118362](https://doi.org/10.1051%2F0004-6361%2F201118362). [S2CID](/source/S2CID_(identifier)) [119275785](https://api.semanticscholar.org/CorpusID:119275785). A53.

1. **[^](#cite_ref-Meshkat2017_11-0)** Meshkat, Tiffany; et al. (December 2017). ["A Direct Imaging Survey of Spitzer-detected Debris Disks: Occurrence of Giant Planets in Dusty Systems"](https://doi.org/10.3847%2F1538-3881%2Faa8e9a). *The Astronomical Journal*. **154** (6): 21. [arXiv](/source/ArXiv_(identifier)):[1710.04185](https://arxiv.org/abs/1710.04185). [Bibcode](/source/Bibcode_(identifier)):[2017AJ....154..245M](https://ui.adsabs.harvard.edu/abs/2017AJ....154..245M). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/aa8e9a](https://doi.org/10.3847%2F1538-3881%2Faa8e9a). [S2CID](/source/S2CID_(identifier)) [42042014](https://api.semanticscholar.org/CorpusID:42042014). 245.

1. **[^](#cite_ref-Soto2015_12-0)** Soto, M. G.; et al. (August 2015). ["RAFT - I. Discovery of new planetary candidates and updated orbits from archival FEROS spectra"](https://doi.org/10.1093%2Fmnras%2Fstv1144). *Monthly Notices of the Royal Astronomical Society*. **451** (3): 3131–3144. [arXiv](/source/ArXiv_(identifier)):[1505.04796](https://arxiv.org/abs/1505.04796). [Bibcode](/source/Bibcode_(identifier)):[2015MNRAS.451.3131S](https://ui.adsabs.harvard.edu/abs/2015MNRAS.451.3131S). [doi](/source/Doi_(identifier)):[10.1093/mnras/stv1144](https://doi.org/10.1093%2Fmnras%2Fstv1144).

1. **[^](#cite_ref-Cotten2016_13-0)** Cotten, Tara H.; Song, Inseok (July 2016). ["A Comprehensive Census of Nearby Infrared Excess Stars"](https://doi.org/10.3847%2F0067-0049%2F225%2F1%2F15). *The Astrophysical Journal Supplement Series*. **225** (1): 24. [arXiv](/source/ArXiv_(identifier)):[1606.01134](https://arxiv.org/abs/1606.01134). [Bibcode](/source/Bibcode_(identifier)):[2016ApJS..225...15C](https://ui.adsabs.harvard.edu/abs/2016ApJS..225...15C). [doi](/source/Doi_(identifier)):[10.3847/0067-0049/225/1/15](https://doi.org/10.3847%2F0067-0049%2F225%2F1%2F15). [S2CID](/source/S2CID_(identifier)) [118438871](https://api.semanticscholar.org/CorpusID:118438871). 15.

## External links

- ["Notes for star HD 70573"](https://web.archive.org/web/20070613004732/http://exoplanet.eu/star.php?st=HD+70573). *[Extrasolar Planets Encyclopaedia](/source/Extrasolar_Planets_Encyclopaedia)*. Archived from [the original](http://exoplanet.eu/star.php?st=HD+70573) on June 13, 2007.

v t e Constellation of Hydra List of stars in Hydra Hydra in Chinese astronomy Stars Bayer α (Alphard) β γ (Naga) δ ε (Ashlesha) ζ η θ ι (Ukdah) κ λ μ ν ξ ο π ρ σ (Minchir) τ1 τ2 υ1 (Zhang) υ2 φ1 φ2 φ3 χ1 χ2 ψ ω b1 b3 C F Flamsteed 1 2 3 6 (a) 9 10 12 (D) 14 15 17 19 20 21 23 24 25 26 27 (P) 28 29 33 (A) 34 37 44 47 48 50 51 (k) 52 (l) 54 (m) 55 56 57 58 (Solitaire) 59 60 10 Crt 17 Crt 20 Crt 2 Sex Variable R U V W TW EX HS KU LQ V361 V419 V421 V478 V484 HR 3378 3538 3749 (G) 3750 3858 (I) 3862 3919 3923 (Felis) 4162 4328 4339 (β Ant) 4445 5265 HD 72659 74156 82943 86226 86264 90156 (γ Ant) Other 2MASS 1114−2618 ESO 439-26 Gliese 328 Gliese 357 Gliese 433 Gliese 453 GJ 3634 HAT-P-30 HE 1256−2738 HE 1327−2326 LHS 2065 LHS 3003 LTT 3780 SDSS J090745.0+024507 WASP-25 WASP-36 WASP-84 WASP-166 (Filetdor) WISE 0855−0714 WISEA J1141−3326 Exoplanets Gliese 357 d HD 72659 b HD 74156 b c HD 82943 b c HD 86226 b HD 86264 b TW Hydrae b (unconfirmed) WASP-193b Star clusters Messier 48 Messier 68 NGC 5694 Price-Whelan 1 Nebulae Abell 33 Abell 35 NGC 3242 Southern Owl Nebula Galaxies Messier 83 NGC 2617 2642 2697 2708 2758 2835 2848 2865 2890 2935 2936 2937 2960 2962 2986 2992 3030 3052 3054 3081 3109 3124 3200 3285 3285B 3290 3305 3307 3308 3309 3311 3312 3313 3314 3315 3316 3336 3369 3383 3393 3402 3463 3464 3585 3621 3673 3717 3904 3923 3936 4980 4993 5042 5061 5078 5085 5101 5135 5260 5264 5495 5626 Other 3C 196.1 AM 1316−241 Arp 7 CTQ 327 ESO 510-G13 GAMA202627 GLEAM J0917−0012 Hydra A IC 535 MRC 1138−262 Peekaboo Galaxy PKS 1151−348 RX J0911.4+0551 SDSS J0841+0101 TN J0924−2201 Tololo 1247−232 ZwCl 1693 BCG Galaxy clusters Abell 754 Abell 3411 Abell 3412 Bullet Group Hickson 40 Astronomical events GW170817 Category

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Adapted from the Wikipedia article [HD 70573](https://en.wikipedia.org/wiki/HD_70573) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/HD_70573?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.