Rho Hydrae information

Rho Hydrae
	Red circle marks arc distance separating other bright stars viewed from our place in the galaxy.
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Hydra
Right ascension	08h 48m 25.97057s
Declination	+05° 50′ 16.1283″
Apparent magnitude (V)	4.34
Characteristics
Spectral type	A0 Vn
U−B color index	−0.04
B−V color index	−0.04
Astrometry
Radial velocity (Rv)	+32.8 km/s
Proper motion (μ)	RA: −17.33 mas/yr ; Dec.: −29.41 mas/yr
Parallax (π)	9.21 ± 0.21 mas
Distance	354 ± 8 ly ; (109 ± 2 pc)
Absolute magnitude (MV)	−0.83
Details
Mass	3.24±0.05 M☉
Radius	2.0 R☉
Luminosity	242 L☉
Temperature	9,795 K
Rotational velocity (v sin i)	128 km/s
Age	350 Myr
Other designations
	ρ Hya, 13 Hya, BD+06°2040, HD 75137, HIP 43234, HR 3492, SAO 117146
Database references
SIMBAD	data

Rho Hydrae, equally written ρ Hydrae, is a binary star^[9] in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 4.34.^[2] The distance to this system, based upon an annual parallax shift of 9.21 mas,^[1] is about 354 light years. At that distance, the visual magnitude is diminished by an interstellar extinction of 0.06 magnitudes, due to intervening dust.^[7]

The primary component is an A-type main sequence star with a stellar classification of A0 Vn.^[3] It has around double^[6] the radius of the Sun and 3.2 times the Sun's mass. Rho Hydrae is around 350 million years old^[7] and has a high rate of spin, with a projected rotational velocity of 128 km/s. It radiates 242 times the solar luminosity from its outer atmosphere at an effective temperature of 9,795 K.^[3] The companion is a magnitude 11.9 star at an angular separation of 12.1 arc seconds along a position angle of 146°, as of 2000.^[10]

^ ^a ^b ^c ^d ^e ^f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
^ Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
^ ^a ^b ^c Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
^ Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).

[vanLeeuwen2007-1] ^ ^a ^b ^c ^d ^e ^f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).

[Mermilliod1986-2] Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).

[Zorec2012-3] Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).

[Wilson1953-4] Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).

[Anderson2012-5] Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).

[PasinettiFracassini2001-6] Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).

[Gontcharov2012-7] Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).

[SIMBAD-8] Cite error: The named reference SIMBAD was invoked but never defined (see the help page).

[Eggleton2008-9] Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).

[WDSC2014-10] Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).

Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Red circle marks arc distance separating other bright stars viewed from our place in the galaxy.
Constellation	Hydra
Right ascension	08^h 48^m 25.97057^s^[1]
Declination	+05° 50′ 16.1283″^[1]
Apparent magnitude (V)	4.34^[2]
Characteristics
Spectral type	A0 Vn^[3]
U−B color index	−0.04^[2]
B−V color index	−0.04^[2]
Astrometry

Radial velocity (R_v)	+32.8^[4] km/s
Proper motion (μ)	RA: −17.33^[1] mas/yr Dec.: −29.41^[1] mas/yr
Parallax (π)	9.21 ± 0.21 mas^[1]
Distance	354 ± 8 ly (109 ± 2 pc)
Absolute magnitude (M_V)	−0.83^[5]

Details^[3]

Mass	3.24±0.05 `M`_☉
Radius	2.0^[6] `R`_☉
Luminosity	242 `L`_☉
Temperature	9,795 K
Rotational velocity (v sin i)	128 km/s
Age	350^[7] Myr

Other designations
ρ Hya, 13 Hya, BD+06°2040, HD 75137, HIP 43234, HR 3492, SAO 117146^[8]
Database references
SIMBAD	data

Rho Hydrae information

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